Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Atlantic Shores South Project Offshore of New Jersey

AGENCY:

National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION:

Proposed rule; proposed letter of authorization; request for comments.

SUMMARY:

NMFS has received a request from Atlantic Shores Offshore Wind LLC (Atlantic Shores), a joint venture between EDF–RE Offshore Development LLC (a wholly owned subsidiary of EDF Renewables, Inc.) and Shell New Energies US LLC, for Incidental Take Regulations (ITR) and associated Letters of Authorization (LOAs) pursuant to the Marine Mammal Protection Act (MMPA). The requested regulations would govern the authorization of take, by Level A harassment and Level B harassment, of small numbers of marine mammals over the course of 5 years (2025–2029) incidental to the construction of Atlantic Shores South located offshore of New Jersey within the Bureau of Ocean Energy Management (BOEM) Commercial Lease of Submerged Lands for Renewable Energy Development on the Outer Continental Shelf (OCS) Lease Area OCS–A 0499 (Lease Area) and associated ECCs (ECR Area). Atlantic Shores South would be divided into two projects: Project 1 and Project 2 (the combined hereafter referred to as the “Project Area”) and Atlantic Shores has requested a 5-year LOA for each Project, both issued under these proposed regulations. Atlantic Shores' activities likely to result in incidental take include impact and vibratory pile driving and site assessment surveys using high-resolution geophysical (HRG) equipment within the Lease Area and Export Cable Corridor (ECC). NMFS requests comments on its proposed rule. NMFS will consider public comments prior to making any final decision on the promulgation of the requested ITR and issuance of the LOA; agency responses to public comments will be summarized in the final rule documenting our decision.

DATES:

The regulations and LOA, if issued, would be effective January 1, 2025 through December 31, 2029. Comments and information must be received no later than October 23, 2023.

ADDRESSES:

Submit all electronic public comments via the Federal e-Rulemaking Portal. Go to www.regulations.gov and enter NOAA–NMFS–2023–0068 in the Search box. Click on the “Comment” icon, complete the required fields, and enter or attach your comments.

Instructions: Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on www.regulations.gov without change. All personal identifying information ( e.g., name, address), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous). Attachments to electronic comments will be accepted in Microsoft Word, Excel, or Adobe PDF file formats only.

FOR FURTHER INFORMATION CONTACT:

Kelsey Potlock, Office of Protected Resources, NMFS, (301) 427–8401.

SUPPLEMENTARY INFORMATION:

Availability

A copy of Atlantic Shores' Incidental Take Authorization (ITA) application and supporting documents, as well as a list of the references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. In case of problems accessing these documents, please call the contact listed above (see FOR FURTHER INFORMATION CONTACT ).

Purpose and Need for Regulatory Action

This proposed rule, if promulgated, would provide a framework under the authority of the MMPA (16 U.S.C. 1361 et seq.) for NMFS to authorize the take of marine mammals incidental to construction of Atlantic Shores South within the Lease Area and along ECCs to two landfall locations in New Jersey. NMFS received a request from Atlantic Shores to incidentally take individuals of 16 species of marine mammals (9 species by Level A harassment and Level B harassment and 7 species by Level B harassment only), comprising 17 stocks, incidental to Atlantic Shores' 5 years of construction activities. No mortality or serious injury is anticipated or proposed for authorization. Please see the Legal Authority for the Proposed Action section below for definitions of harassment, serious injury, and incidental take.

Legal Authority for the Proposed Action

The MMPA prohibits the “take” of marine mammals, with certain exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made, regulations are promulgated (when applicable), and public notice and an opportunity for public comment are provided.

Authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s) and will not have an unmitigable adverse impact on the availability of the species or stock(s) for taking for subsistence uses (where relevant). If such findings are made, NMFS must prescribe the permissible methods of taking; “other means of effecting the least practicable adverse impact” on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stocks for taking for certain subsistence uses (referred to as “mitigation”); and requirements pertaining to the monitoring and reporting of such takings.

As noted above, no serious injury or mortality is anticipated or proposed for authorization in this proposed rule. Relevant definitions of MMPA statutory and regulatory terms are included below:

• U.S. Citizen —individual U.S. citizens or any corporation or similar entity if it is organized under the laws of the United States or any governmental unit defined in 16 U.S.C. 1362(13) (50 CFR 216.103);

• Take —to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal (16 U.S.C. 1362(13); 50 CFR 216.3);

• Incidental harassment, incidental taking, and incidental, but not intentional, taking —an accidental taking. This does not mean that the taking is unexpected, but rather it includes those takings that are infrequent, unavoidable or accidental (see 50 CFR 216.103);

• Serious Injury —any injury that will likely result in mortality (50 CFR 216.3);

• Level A harassment —any act of pursuit, torment, or annoyance which has the potential to injure a marine mammal or marine mammal stock in the wild (16 U.S.C. 1362(18); 50 CFR 216.3); and

• Level B harassment —any act of pursuit, torment, or annoyance which has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (16 U.S.C. 1362(18); 50 CFR 216.3).

Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I provide the legal basis for proposing and, if appropriate, issuing regulations and an associated LOA(s). This proposed rule describes permissible methods of taking and mitigation, monitoring, and reporting requirements for Atlantic Shores' proposed activities.

Summary of Major Provisions Within the Proposed Rule

The major provisions of this proposed rule include:

• The proposed take of marine mammals by Level A harassment and/or Level B harassment;
• No mortality or serious injury of any marine mammal is anticipated or proposed to be authorized;

• The establishment of a seasonal moratorium on wind turbine generator (WTG), meteorological tower (Met Tower), and offshore substation (OSS) foundation impact pile driving during the months of highest North Atlantic right whale ( Eubalaena glacialis) presence in the Project Area (December 1st–April 30th), unless NMFS allows for pile driving to occur in December;

• A requirement for both visual and passive acoustic monitoring to occur by trained, NOAA Fisheries-approved Protected Species Observers (PSOs) and Passive Acoustic Monitoring (PAM; where required) operators before, during, and after select activities;
• A requirement for training for all Atlantic Shores personnel to ensure marine mammal protocols and procedures are understood;
• The establishment of clearance and shutdown zones for all in-water construction activities to prevent or reduce the risk of Level A harassment and to minimize the risk of Level B harassment;
• A requirement to use sound attenuation device(s) during all foundation impact pile driving installation activities to reduce noise levels to those modeled assuming 10 decibels (dB);
• A delay to the start of foundation installation if a North Atlantic right whale is observed at any distance by PSOs or acoustically detected within certain distances;
• A delay to the start of foundation installation if other marine mammals are observed entering or within their respective clearance zones;
• A requirement to shut down impact pile driving (if feasible) if a North Atlantic right whale is observed or if any other marine mammals are observed entering their respective shutdown zones;

• A requirement to implement sound field verification during impact pile driving of foundation piles to measure in situ noise levels for comparison against the modeled results;

• A requirement to implement soft-starts during impact pile driving using the least amount of hammer energy necessary for installation;
• A requirement to implement ramp-up during the use of high-resolution geophysical (HRG) marine site characterization survey equipment;
• A requirement for PSOs to continue to monitor for 30 minutes after any impact pile driving for foundation installation;
• A requirement for the increased awareness of North Atlantic right whale presence through monitoring of the appropriate networks and Channel 16, as well as reporting any sightings to the sighting network;
• A requirement to implement various vessel strike avoidance measures;
• A requirement to implement measures during fisheries monitoring surveys, such as removing gear from the water if marine mammals are considered at-risk or are interacting with gear; and
• A requirement for frequently scheduled and situational reporting including, but not limited to, information regarding activities occurring, marine mammal observations and acoustic detections, and sound field verification monitoring results.

NMFS must withdraw or suspend any LOA(s), if issued under these regulations, after notice and opportunity for public comment, if it finds the methods of taking or the mitigation, monitoring, or reporting measures are not being substantially complied with (16 U.S.C. 1371(a)(5)(B); 50 CFR 216.206(e)). Additionally, failure to comply with the requirements of the LOA(s) may result in civil monetary penalties and knowing violations may result in criminal penalties (16 U.S.C. 1375).

National Environmental Policy Act (NEPA)

To comply with the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216–6A, NMFS must evaluate the proposed action ( i.e., promulgation of regulations) and alternatives with respect to potential impacts on the human environment.

Accordingly, NMFS proposes to adopt the BOEM Environmental Impact Statement (EIS) for Atlantic Shores South, provided our independent evaluation of the document finds that it includes adequate information analyzing the effects of promulgating the proposed regulations and issuance of the LOA(s) on the human environment. NMFS is a cooperating agency on BOEM's EIS. BOEM's Atlantic Shores South Draft Environmental Impact Statement for Commercial Wind Lease OCS–A 0499 (DEIS), was made available for public comment through a Notice of Availability on May 19, 2023 (88 FR 32242), available at https://www.boem.gov/renewable-energy/state-activities/atlantic-shores-south . The DEIS had a 45-day public comment period; the comment period was open from May 19, 2023 to July 3, 2023. Additionally, BOEM held two in-person public meetings, on June 21, 2023 and June 22, 2023, and two virtual public hearings, on June 26, 2023, and June 28, 2023.

Information contained within Atlantic Shores' ITA application and this Federal Register document provide the environmental information related to these proposed regulations and associated 5-year LOA for public review and comment. NMFS will review all comments submitted in response to this proposed rulemaking prior to concluding our NEPA process or making a final decision on the requested 5-year ITR and associated LOAs.

Fixing America's Surface Transportation Act (FAST–41)

This project is covered under Title 41 of the Fixing America's Surface Transportation Act or “FAST–41.” FAST–41 includes a suite of provisions designed to expedite the environmental review for covered infrastructure projects, including enhanced interagency coordination as well as milestone tracking on the public-facing Permitting Dashboard. FAST–41 also places a 2-year limitations period on any judicial claim that challenges the validity of a Federal agency decision to issue or deny an authorization for a FAST–41 covered project (42 U.S.C. 4370m-6(a)(1)(A)).

Atlantic Shores' proposed project is listed on the Permitting Dashboard, where milestones and schedules related to the environmental review and permitting for the project can be found at https://www.permits.performance.gov/permitting-project/atlantic-shores-south .

Summary of Request

On February 8, 2022, NMFS received a request from Atlantic Shores for the promulgation of regulations and the issuance of associated LOAs to take marine mammals incidental to construction activities associated with the Atlantic Shores South project located offshore of New Jersey in Lease Area OCS–A 0499 and associated ECCs. Atlantic Shores' request is for the incidental, but not intentional, take of a small number of 16 marine mammal species (comprising 17 stocks) by Level A harassment and/or Level B harassment. Neither Atlantic Shores nor NMFS expects serious injury and/or mortality to result from the specified activities, and Atlantic Shores did not request, and NMFS is not proposing, to authorize mortality or serious injury of any marine mammal species or stock.

In response to our questions and comments and following extensive information exchanges with NMFS, Atlantic Shores submitted a final, revised application on August 12, 2022 that NMFS deemed adequate and complete on August 25, 2022. The final version of the application is available on NMFS' website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores .

On September 29, 2022, NMFS published a notice of receipt (NOR) of the adequate and complete application in the Federal Register (87 FR 59061), requesting public comments and information related to Atlantic Shores' request during a 30-day public comment period. Due to a request, NMFS extended the public comment period for an additional 15 days (87 FR 65193, October 28, 2022) for a total of a 45-day public comment period. During the 45-day NOR public comment period, NMFS received 5 comments and letters from the public, including a citizen, environmental non-governmental organization (eNGO), and local citizen group. NMFS has reviewed all submitted material and has taken these into consideration during the drafting of this proposed rule.

In June 2022, Duke University's Marine Spatial Ecology Laboratory released updated habitat-based marine mammal density models (Roberts et al., 2016; Roberts et al., 2023). Because Atlantic Shores applied previous marine mammal densities to their analysis in their application, Atlantic Shores submitted a final Updated Density and Take Estimation Memo (herein referred to as Updated Density and Take Estimation Memo) on March 28, 2023 that included marine mammal densities and take estimates based on these new models. This memo can be found on NMFS' website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores .

In January and February 2023, Atlantic Shores informed NMFS that the proposed activity had changed from what was presented in the adequate and complete MMPA application. Specifically, Atlantic Shores committed to installing only monopile WTG foundations for Project 1 (and any found in the associated Overlap Area), as opposed to either monopile or jacket foundations. All WTGs built for Project 2 (and any remaining Overlap Area) may still consist of either monopiles or jacket foundations and remain unchanged as presented in the adequate and complete MMPA application. Additionally, all OSS foundations that could be developed across both Projects 1 and 2 continue to maintain build-outs using only jacket foundations. Atlantic Shores provided a memo and supplemental materials outlining these changes to NMFS on March 31, 2023. These supplemental materials can be found on NMFS' website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores .

NMFS has previously issued seven Incidental Harassment Authorizations (IHAs), including one renewed IHA and one correction to an issued IHA, to Atlantic Shores authorizing take incidental to high-resolution site characterization surveys offshore New Jersey (see 85 FR 21198, April 16, 2020; 86 FR 21289, April 22, 2021 (renewal); 87 FR 24103, April 22, 2022; and 88 FR 38821, June 14, 2023).

To date, Atlantic Shores has complied with all the requirements ( e.g., mitigation, monitoring, and reporting) of the previous IHAs and information regarding Atlantic Shores' take estimates and monitoring results may be found in the Estimated Take section. Final monitoring reports can be found on NMFS' website, along with previously issued IHAs: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable .

On August 1, 2022, NMFS announced proposed changes to the existing North Atlantic right whale vessel speed regulations (87 FR 46921, August 1, 2022) to further reduce the likelihood of mortalities and serious injuries to endangered right whales from vessel collisions, which are a leading cause of the species' decline and a primary factor in an ongoing Unusual Mortality Event (UME). Should a final vessel speed rule be issued and become effective during the effective period of these regulations (or any other MMPA incidental take authorization), the authorization holder would be required to comply with any and all applicable requirements contained within the final vessel speed rule. Specifically, where measures in any final vessel speed rule are more protective or restrictive than those in this or any other MMPA authorization, authorization holders would be required to comply with the requirements of the rule. Alternatively, where measures in this or any other MMPA authorization are more restrictive or protective than those in any final vessel speed rule, the measures in the MMPA authorization would remain in place. The responsibility to comply with the applicable requirements of any vessel speed rule would become effective immediately upon the effective date of any final vessel speed rule and, when notice is published on the effective date, NMFS would also notify Atlantic Shores if the measures in the speed rule were to supersede any of the measures in the MMPA authorization such that they were no longer required.

Description of the Specified Activities

Overview

Atlantic Shores has proposed to construct and operate two offshore wind projects (Project 1 and Project 2), collectively known as Atlantic Shores South in Lease Area OCS–A 0499. This lease area is located within the New Jersey Wind Energy Area (NJ WEA). Collectively, Atlantic Shores South will consist of up to 200 WTGs, 10 OSSs, and 1 Met Tower divided into two projects: Project 1 and Project 2. These Projects would assist the State of New Jersey to meet its renewable energy goals under the New Jersey Offshore Wind Economic Development Act (OWEDA). Atlantic Shores has been given an allowance by the New Jersey Board of Public Utilities, through an Offshore Renewable Energy Certificate (OREC), to construct a facility capable of delivering 1,510 megawatts (MW) of renewable energy to the State of New Jersey through Project 1 (owned by an affiliate of Atlantic Shores, called Atlantic Shores Offshore Wind Project 1, LLC). Atlantic Shores also intends to compete for a second OREC award through a competitive solicitation process to develop Project 2, which will be owned by another affiliate company of Atlantic Shores, Atlantic Shores Offshore Wind Project 2, LLC.

The Project would consist of several different types of permanent offshore infrastructure, including up to 200 15–MW WTGs and up to 10 OSSs; a single Met Tower; and OSS array cables and interconnector cables. All permanent foundations (WTGs, OSSs, and the single Met Tower) would be installed using impact pile driving only. For the permanent foundations, Atlantic Shores originally considered three construction scenarios for the completion of Projects 1 and 2. All three schedules assume a start year of 2026 for WTG, Met Tower, and OSS foundation installation. Construction Schedules 1 and 3 assume monopile foundations for all WTGs and the Met Tower across both Projects 1 and 2. Construction Schedule 2 originally assumed a full jacket foundation buildout for both Project 1 and Project 2. However, Atlantic Shores has modified Schedule 2 to now assume that all WTGs and the Met Tower in Project 1 would be built using monopiles; the WTGs for Project 2 would still consist of either jacket or monopile foundations. In all Construction Schedules, the OSS foundations would always be built out using jacket foundations. However, these may vary in size between the two Projects ( i.e., small, medium, or large OSSs). Under Schedules 1 and 2, foundations would be constructed in 2 years. Under Schedule 3, all permanent foundations would be installed within a single year.

Atlantic Shores would also conduct the following specified activities: temporarily install and remove, by vibratory pile driving, up to eight nearshore cofferdams to connect the offshore export cables to onshore facilities; deploy up to four temporary meteorological and oceanographic (metocean) buoys (three in Project 1 and one in Project 2); several types of fishery and ecological monitoring surveys; the placement of scour protected, trenching, laying, and burial activities associated with the installation of the export cable route from OSSs to shore-based switching and substations and inter-array cables between turbines; HRG vessel-based site characterization and assessment surveys using active acoustic sources with frequencies of less than 180 kilohertz (kHz); transit within the Project Area and between ports and the Lease Area to transport crew, supplies, and materials to support pile installation via vessels; and WTG operation. All offshore cables would be connected to onshore export cables at the sea-to-shore transition points located in Atlantic City, New Jersey (Atlantic Landfall Site) and in Sea Girt, New Jersey (Monmouth Landfall Site). From the sea-to-shore transition point, onshore underground export cables are then connected in series to switching stations/substations, overhead transmission lines, and ultimately to the grid connection. No detonations of unexploded ordnance or munitions and explosives of concern (UXOs/MECs) were planned to occur, nor are they included in this proposed rule. Therefore, these are not discussed further.

Marine mammals exposed to elevated noise levels during impact and vibratory pile driving and site characterization surveys may be taken, by Level A harassment and/or Level B harassment, depending on the specified activity. No serious injury or mortality is anticipated or proposed for authorization.

Dates and Duration

Atlantic Shores anticipates that activities with the potential to result in incidental take of marine mammals would occur throughout all 5 years of the proposed regulations which, if issued, would be effective from January 1, 2025 through December 31, 2029. Based on Atlantic Shores' proposed schedule, the installation of all permanent structures would be completed by the end of November 2026. More specifically, the installation of WTG and OSS foundations is expected to occur between May–December in both 2026 and 2027. The temporary cofferdams used for nearshore cable landfall construction would be installed and subsequently removed anytime within 2025 and 2026. The Met Tower would be installed alongside WTGs in Project 1 (2026). Lastly, Atlantic Shores anticipates HRG survey activities using boomers, sparkers, and Compressed High-Intensity Radiated Pulses (CHIRPs) to occur annually and across the entire 5-year effective period of the proposed rule. These HRG surveys are not planned to occur concurrently to pile driving activities but they may occur across the entire Atlantic Shores South Lease Area and ECCs and may take place at any time of year.

Atlantic Shores has provided a schedule for all of their proposed construction activities (Table 1). This table also presents a breakdown of the timing and durations of the activities proposed to occur during the construction and operation of the Atlantic Shores South project.

Atlantic Shores anticipates the installation of all offshore components for Atlantic Shores South are expected to take up to 3 years to complete. During the construction period, Atlantic Shores plans for Project 1 WTGs to be commissioned in 2026 and for Project 2 WTGs to be commissioned in 2027. Atlantic Shores anticipates that Projects 1 and 2 would become operational in 2028 and 2029, respectively. However, these schedules are subject to change based on the contracting and permitting needs of the projects.

Specific Geographic Region

Atlantic Shores would construct and operate Atlantic Shores South (both Project 1 and Project 2) in Federal and state waters offshore New Jersey within Lease Area OCS–A–0499 and associated ECCs (Figure 1). The Lease Area covers approximately 413.3 square kilometers (km² ; 102,124 acres) and begins approximately 8.7 miles (mi; 14 km) from the New Jersey shoreline. The area for Project 1 measures approximately 219.2 km² (54,175 acres) and is located in the western part of the Project Area; the area for Project 2 consists of approximately 182.2 km² (45,013 acres) and is located along the eastern part of the Project Area. The Overlap Area, which would be split between Projects 1 and 2, consists of an area measuring approximately 11.9 km² (2,936 acres). The water depths in the Lease Area range from 19 to 37 meters (m; 62 to 121 feet (ft)) while water depths along the Atlantic City ECC range from 0 to 22 m (0 to 72 ft) and the Monmouth ECC ranges from 0 to 30 m (0 to 98 ft). Within the Project Area, water depths gradually increase based on distance from shore. Cable landfall construction work ( i.e., temporary cofferdams) would be conducted in shallow waters of 4 to 7.5 m (13.1 to 24.6 ft) deep. Sea surface temperatures range from 41 to 73 degrees Fahrenheit (°F; 5 to 23 degrees Celsius (°C)).

Atlantic Shores' specified activities would occur within the Northeast U.S. Continental Shelf Large Marine Ecosystem (NES LME), an area of approximately 260,000 km² (64,247,399.2 acres) from Cape Hatteras in the south to the Gulf of Maine in the north. Specifically, the lease area and cable corridor are located within the Mid-Atlantic Bight sub-area of the NES LME which extends between Cape Hatteras, North Carolina, and Martha's Vineyard, Massachusetts, extending westward into the Atlantic to the 100-m isobath. In the Middle Atlantic Bight, the pattern of sediment distribution is relatively simple. The continental shelf south of New England is broad and flat, dominated by fine grained sediments. Most of the surficial sediments on the continental shelf are sands and gravels. Silts and clays predominate at and beyond the shelf edge, with most of the slope being 70–100 percent mud. Fine sediments are also common in the shelf valleys leading to the submarine canyons. There are some larger materials, left by retreating glaciers, along the coast of Long Island and to the north and east.

Primary productivity is highest in the nearshore and estuarine regions, with coastal phytoplankton blooms initiating in the winter and summer, although the timing and spatial extent of blooms varies from year to year. The relatively productive continental shelf supports a wide variety of fauna and flora, making it important habitat for various benthic and fish species and marine mammals, including but not limited to, fin whales, humpback whales, North Atlantic right whales, and other large whales as they migrate through the area. The Cold Pool, a bottom-trapped cold, nutrient-rich pool and distinct oceanographic feature of the Mid-Atlantic Bight, creates habitat that provides thermal refuge to cold water species in the area (Atlantic Shores South Construction and Operations Plan (COP), Volume II; Lentz, 2017). Cold Pool waters, when upwelled to the surface, promote primary productivity within this region (Voynova et al., 2013).

The seafloor in the Atlantic Shores South Project Area is dynamic and changes over time due to current, tidal flows, and wave conditions. The benthic habitat of the Project Area contains a variety of seafloor substrates, physical features, and associated benthic organisms. The soft bottom sediments in the Project Area are reflective of the rest of the Mid-Atlantic Bight region, and are characterized by fine sand as well as gravel and silt/sand mixes (Milliman, 1972; Steimle and Zetlin, 2000). The offshore Project Area is dominated by fine, medium, and coarse sand. The ECCs consist of medium to coarse sand offshore. The Atlantic City ECC is characterized by fine sand nearshore while the Monmouth ECC largely consists of medium and fine sand in the nearshore portion (Atlantic Shores, 2021). The benthic community within the offshore Project Area is characterized by echinoderms, bivalves, gastropods, polychaetes, oligochaetes, amphipods, crustaceans, and cnidarians (Atlantic Shores, 2021).

Additional information on the underwater environment's physical resources can be found in the COP for the Atlantic Shores South project (Atlantic Shores, 2021) available at https://www.boem.gov/renewable-energy/state-activities/atlantic-shores-offshore-wind-construction-and-operations-plan.

Figure 1—Project Location

Detailed Description of Specified Activities

Below we provide detailed descriptions of Atlantic Shores' proposed activities, explicitly noting those that are anticipated to result in the take of marine mammals and for which an incidental take authorization is requested. Additionally, a brief explanation is provided for those activities that are not expected to result in the take of marine mammals.

WTG, OSS, and Met Tower Foundation Installation

Atlantic Shores South, in total, includes up to 200 WTGs, a single Met Tower, and up to 10 OSS. As described above, Atlantic Shores has proposed to divide Atlantic Shores South into two projects. Project 1 and Project 2 (including any relevant Overlap Area allocated) would be electrically distinct in all ways and energy produced from the Projects' OSSs would transmit energy to shore via 230–275 kilovolts (kV) High Voltage Alternating Current (HVAC) and/or 320–525 kV high voltage direct current (HVDC) export cables (a maximum of eight cables would be used) to two landfall locations located near Atlantic City, New Jersey and at the Monmouth site located near Sea Girt, New Jersey. Project 1 would include 105 to 111 WTGs on monopile foundations while Project 2 would include 89 to 95 WTGs on either monopile or jacket foundations. Monopiles would be either 12 m (39.37 ft) or 15 m (49.21 ft) in diameter. The number of OSSs in each project is dependent upon the foundation size. Project 1 may contain five small, two medium, or two large OSSs while Project 2 may contain up to five small, three medium, or two large OSSs. OSSs would be located on jacket foundations using 5 m (16.4 ft) pin piles and could consist of a four-legged (small OSS), six-legged (medium OSS), or eight-legged (large OSS) design. Atlantic Shores would also construct a Met Tower in Project 1 on a monopile foundation. Atlantic Shores has indicated that monopiles, suction bucket jackets, mono-suction buckets, and gravity-base structures may also be used (particularly for the construction of the Met Tower and depending on the size of OSSs built, per Atlantic Shores' Project Design Envelope (PDE) refinement memo). However, for purposes of this analysis, the use of suction buckets and gravity-bases to secure bottom-frame foundations are not being considered further in this analysis as the installation of bottom-frame foundations using suction buckets or gravity-base foundations are not anticipated to result in noise levels that would cause harassment to marine mammals. Small OSSs built on monopile foundations would produce less Level B harassment than if they were built on jacket foundations, as indicated in the ITA application, as more piles would need to be driven by an impact hammer. Hence, we limit our analysis in this proposed rule to foundations which require the maximum amount of impact pile driving possible.

A monopile foundation typically consists of a single steel tubular section with several sections of rolled steel plate welded together and secured to the seabed. Secondary structures on each WTG monopile foundation could include a boat landing or alternative means of safe access, ladders, a crane, and other ancillary components. A typical monopile installation sequence begins with the monopiles transported directly to the Project Area for installation or to the construction staging port by an installation vessel or a feeding barge. At the foundation location, the main installation vessel upends the monopile in a vertical position in the pile gripper mounted on the side of the vessel. The hammer is then lifted on top of the pile and pile driving commences with a soft-start and proceeds to completion. Piles are driven until the target embedment depth is met, then the pile hammer is removed and the monopile is released from the pile gripper. Once installation of the monopile is complete, the vessel moves to the next installation location.

All monopile foundations ( i.e., 15-m or 12-m) would be installed using a 4,400 kilojoule (kJ) impact hammer ( i.e., Menck MHU 4400S) to obtain a maximum penetration depth of 60 m (197 ft). Atlantic Shores estimates that a 15-m monopile could require up to 15,387 strikes at a rate of up to 30 blows per minute (bpm) to reach the target penetration depth, while a 12-m monopile could require 12,350 total strikes at a rate of 30 bpm. Each monopile is estimated to take between 7 to 9 hours to install using an impact hammer. In most cases, Atlantic Shores anticipates installing one monopile per day. However, they may install up to two monopiles per day if possible. For jacket foundations, pin piles would be installed using a 2,500 kJ hammer ( i.e., IHC S–2500) to reach a maximum penetration depth of 70 m (230 ft). Each pin pile would need an estimated 3 hours of impact hammering to reach the target penetration depth, with up to 12 hours needed per day to install four pin piles (one jacket foundation). Impact hammering for pin piles would require up to 6,750 strikes at a rate of up to 30 bpm.

Jackets would be lifted off the transport or installation vessel and lowered to the seabed with the correct orientation. The piles would be driven to the engineered depth, following the same process described above for monopiles. The jacket piles are expected to be pre-piled ( i.e., the jacket structure will be set on pre-installed piles) or post-piled ( i.e., the jacket is placed on the seafloor and piles are subsequently driven through guides at the base of each leg). Figure 2 in Atlantic Shores' ITA application provides a conceptual design of monopile and jacket foundations that may be used for Atlantic Shores South.

No concurrent pile driving is planned to occur ( i.e., only one pile would be installed at any given time). Pile driving would not be initiated at night. Nighttime pile driving is not planned; however, if a pile is started 1.5 hours prior to civil sunset and does not pause for more than 30 minutes once visibility is diminished due to darkness during daylight and would necessitate being finished during nighttime hours, Atlantic Shores may complete impact pile driving during night to avoid stability or safety issues. Pile driving associated with foundation installation could occur within the 8-month period of May through December, annually.

Atlantic Shores presented three schedules in their application to construct Atlantic Shores South which contained various foundation types for both projects. However, since that time, Atlantic Shores has narrowed their scope for Project 1 which effectively eliminates Schedule 1 and Schedule 3 from potential scenarios. Atlantic Shores has determined all WTG and Met Tower foundations in Project 1 would be monopiles (maximum size of 15-m). However, they retained the description for Project 2 such that either monopiles or jacket foundations could be used. For both Project 1 and Project 2, OSSs would still be built out using jacket foundations. The 2-year construction timeline described for Schedule 2 in their application remains valid. Hence, NMFS is considering this modified Schedule 2 for purposes of this proposed rule.

All foundation installation for Project 1 plus the Overlap Area ( i.e., 112 WTGs, 1 Met Tower, and 2 OSSs) would occur during construction year 1. For Project 2, 6 WTG foundations would be installed in year 1 and 89 WTG foundations and 2 OSS would be installed in construction year 2. All foundations would be installed in 2026 and 2027, the second and third year of the proposed effective period of this rulemaking. Based on the overall pile driving schedule, Atlantic Shores estimates up to 112 pile driving days for WTGs/Met Tower and up to 12 days for OSS pin pile installation would be needed in construction year 1 (2026). Up to 89 days for WTG installation would be needed in construction year 2 (2027) with another 12 days necessary for the installation of Project 2's OSSs. This estimates a total of 201 days needed to install WTGs (on either a jacket or monopile foundation) and up to 24 days for OSS jacket foundation installation.

Installation of the WTG, Met Tower, and OSS foundations is anticipated to result in the take, by Level A harassment and Level B harassment, of marine mammals due to noise generated during impact pile driving. No vibratory pile driving or drilling of foundations would occur.

Cable Landfall Construction

Atlantic Shores would bring the Atlantic Shores South offshore export cables to shore at the Atlantic landfall site for Project 1, located east of the Project Area and the Monmouth landfall site for Project 2, located north of the Project Area (see Figure 1). The Atlantic Shores South export cable would be connected to the onshore transmission cable at the landfall locations using horizontal directional drilling (HDD) and potentially a backhoe dredge. Atlantic Shores would construct temporary cofferdams using sheet piles to temporarily “dewater” a specified enclosed area using pumps to allow for excavation of the HDD pit. Once excavation and drilling are completed and the HDD conduit and export cable are installed, the seabed would be restored and water would be allowed to flow back in, following the removal of the temporary cofferdam.

Atlantic Shores anticipates installing up to eight temporary cofferdams, with four located at each of two main landfall locations (although fewer may be needed). Each cofferdam is anticipated to measure 30 m x 8 m (98.4 ft x 26.2 ft) in size and would be made up of up to 109 sheet piles which would be both installed and removed by vibratory pile driving methods. This yields a total of 436 sheet piles across all four cofferdams at each landfall location, yielding a total of 872 sheet piles for both landfall locations. Atlantic Shores estimates they can install or remove approximately 13–14 sheet piles per day, assuming 8 hours of vibratory pile driving would occur within any 24-hour period. Given different depths found at the Monmouth and Atlantic landfall sites, the work at Monmouth would take longer (due to deeper waters). The shallower depths found at the Atlantic landfall site would necessitate shorter vibratory pile driving durations. Hence, up to 16 days of work (8 days to install, 8 days to remove) would be required for all cofferdams at the Monmouth landfall site and up to 12 days of work (6 days to install, 6 days to remove) would be necessary for all cofferdams at the Atlantic landfall site. In total, to install and remove all eight cofferdams across both sites, 28 days of vibratory hammering/removal would need to occur. Installation of the temporary cofferdams is anticipated to result in the take, by Level B harassment, of marine mammals due to noise during vibratory driving.

Marine Site Assessment Surveys (e.g., HRG)

Atlantic Shores would conduct site assessment surveys in the Project Area, including the Lease Area and along potential ECCs to landfall locations in New Jersey throughout construction and operation occurring within the 5-year period of the proposed rulemaking. These activities would include:

• Shallow penetration sub-bottom profiler (pingers/CHIRPs) to map the near surface stratigraphy (top 0 ft to 16 ft (0 m to 5 m) soils below seabed);
• Medium penetration sub-bottom profiler (CHIRPs/parametric profilers/sparkers) to map deeper subsurface stratigraphy as needed (soils down to 246 ft (75 m) to 328 ft (100 m) below the seabed);

• Grab sampling to validate seabed classification using typical sample sizes between 0.1 square meters (m² ) and 0.2 m² ;

• Depth sounding (multibeam depth sounder and single beam echosounder) to determine water depths and general bottom topography (currently estimated to range from approximately 16 ft (5 m) to 131 ft (40 m) in depth);
• Seafloor imaging (side scan sonar survey) for seabed sediment classification purposes, to identify natural and man-made acoustic targets resting on the bottom as well as any anomalous features; and
• Magnetic intensity measurements (gradiometer) for detecting local variations in regional magnetic field from geological strata and potential ferrous objects on and below the bottom.

These site assessment surveys may utilize acoustic equipment such as multibeam echosounders, side scan sonars, shallow penetration sub-bottom profilers (SBPs) ( e.g., CHIRP non-parametric SBP), medium penetration sub-bottom profilers ( e.g., sparkers), and ultra-short baseline positioning equipment, some of which are expected to result in the take of marine mammals. Surveys would occur annually, with durations dependent on the activities occurring in that year ( i.e., construction years versus operational years). Use of gradiometers and grab sampling techniques do not have the potential to result in harassment of marine mammals ( e.g.,85 FR 7926, February 12, 2020) and will not be discussed further. Of the HRG equipment proposed for use, the following sources have the potential to result in take of marine mammals:

• Shallow penetration SBPs to map the near-surface stratigraphy (top 0 to 5 m (0 to 16 ft) of sediment below seabed). A CHIRP system emits sonar pulses that increase in frequency over time. The pulse length frequency range can be adjusted to meet project variables. These are typically mounted on the hull of the vessel or from a side pole.
• Medium penetration SBPs (sparkers) to map deeper subsurface stratigraphy as needed. A sparker creates acoustic pulses from 50 Hz to 4 kHz omni-directionally from the source that can penetrate several hundred meters into the seafloor. These are typically towed behind the vessel with adjacent hydrophone arrays to receive the return signals.

Table 2 identifies all the representative HRG survey equipment that may be used during construction of Atlantic Shores South.

While the Applied Acoustics Dura-Spark 240 is planned to be used during project activities, the equipment specifications and subsequent analysis are based on the SIG ELC 820 with a power level of 750 J at a 5 meter depth (Crocker and Fratantonio (2016)). However, while 750 J was used as a worst-case scenario to conservatively account for take of marine mammals as these higher electrical outputs would only be used in areas with denser substrates (700 to 800 J), Atlantic Shores expects a more reasonable power level to be 500 to 600 J based on prior experience with HRG surveys.

Of the sources described in Table 2 above, the only sources expected to result in the harassment of marine mammals are CHIRPs and sparkers. Given the combination of characteristics of the non-impulsive sources planned for use, which include operating frequencies mostly above 180 kHz (considered outside of the hearing range of most marine mammals) and/or very narrow beamwidths, harassment is not expected to result from the operation of any of these sources; therefore, they are not considered further in this proposed rule.

Atlantic Shores' HRG surveys would utilize up to three vessels working concurrently in different sections of the Lease Area and ECCs. No HRG surveys would occur concurrently with impact pile driving activities. All vessels would be operating several kilometers apart at any one time. On average, 55 km (34.2 mi) would be surveyed each survey day, per vessel, at a speed of approximately 6.5 km/hour (3.5 knots (kn; 4 miles per hour (mph))) on a 24-hour basis. During the 5 years the proposed rule would be effective, an estimated area of 413.3 km² (102,124 acres) would be surveyed across the Project Area. Atlantic Shores anticipates up to 60 days of survey activities would occur annually, with 300 days total expected throughout the entire 5-year effective period of the proposed rule.

Meteorological Buoy Deployment

Atlantic Shores will also deploy up to four meteorological and oceanographic (called “metocean”) buoys within the Atlantic Shores South Project Area. Three of these would be located in Project 1 and one would be located in Project 2. These buoys would be designed to collect different data than obtained by the Met Tower and would only be anticipated to collect data ( e.g., wind resource and metocean data) during 1–2 years of the pre-construction period to support the development of Atlantic Shores' projects. Buoys would be deployed approximately 6 months prior to the start of construction and would remain deployed throughout construction activities. Deployed buoys would be decommissioned after construction was completed.

At the time of drafting this proposed rule, Atlantic Shores had not chosen a buoy supplier, so exact design specifics are not certain. However, the buoys will be similar, though smaller, than those deployed in Atlantic Shores' Site Assessment Plan (SAP). We discuss those here for context and to support our analysis of likely buoy effects. Available information on Atlantic Shores' proposed buoy deployments is also available in their COP (Volume I, Section 4.6.2 Temporary Metocean Buoys).

Under the SAP, four buoys (specifically the Fugro SEAWATCH^TM Wind light detection and ranging (LiDAR) buoy) would be deployed (numbered IA1–IA4 in the SAP, with one located in the northern portion of the project (IA2) and three located in the middle and southern portion (IA1, IA3, and IA4) (Figure1–1; Tetra Tech, 2020). The mooring design for the buoys consists of galvanized chains that would connect the buoy to a large link steel chain weight located on the seafloor. A second steel link chain would connect to a water-level acoustic modem via a bottom weight. The chain for the buoy would attach to the base of the SEAWATCH^TM Wavescan platform via a long keel structure. The diameter of the link in the chafe section of the mooring is 19 millimeters. The maximum area that the anchor chain could sweep is estimated as 3.1 acres (0.0048 square miles (mi² )), assuming the chain's radius is 63 meters (207 feet). The approximate sweep of the acoustic modem's chain is approximately 50 meters (164 ft). Figure 3–2 in the SAP demonstrates the buoy mooring design (Tetra Tech, 2020).

Entanglement can occur if wildlife becomes immobilized in survey lines, cables, nets, or other equipment that is moving through the water column. Atlantic Shores incorporated BOEM's Mid-Atlantic Environmental Assessment (EA), which references a NMFS Biological Opinion on the Cape Wind Energy Project (NMFS, 2010) in Nantucket Sound where metocean buoys were used. The EA, as well as a study by Harnois et al. (2015) assessed the potential entanglement risk of metocean buoy mooring systems on marine mammals and determined that there is an extremely low probability that animals would interact with the buoys, which would indicate a low risk of entanglement. Based on the high tension of the chain proposed for use, as well as the material of the chain (galvanized chains versus rope), Harnois et al. (2015) determined that the risk of entanglement to marine mammals was low. Furthermore, given that these buoys would not have any active acoustic components and do not pose a risk of take of marine mammals, Atlantic Shores did not request, and NMFS does not propose to authorize, take associated with the metocean buoys and these are not analyzed further in this document.

Cable Laying and Installation

Cable burial operations would occur both in the Lease Area and ECCs from the lease area to shore. The inter-array cables would connect the WTGs to any one of the OSSs. Cables within the ECCs would carry power from the OSSs to shore at the landfall locations in Atlantic City, New Jersey and Sea Girt, New Jersey. The offshore export and inter-array cables would be buried in the seabed at a target depth of up to 1.5 m (5 ft) to 2 m (6.6 ft), although the exact depth will depend on the substrate in the area. All cable burial operations would follow installation of the WTG and OSS foundations, as the foundations must be in place to provide connection points for the export cables and inter-array cables.

Cable laying, cable installation, and cable burial activities planned to occur during the construction of the Atlantic Shores South project would include the following methods: simultaneous lay and burial for export cable installation, post-lay burial for inter-array cables, and pre-lay trenching for cable burial that is necessary to be deeper than target depth and/or cable burial in firmer ground such as clays or dense sands. Atlantic Shores is evaluating the use of the following techniques to achieve the target cable burial depth: jet plowing for simultaneous lay and burial, jet trenching for simultaneous lay and burial or post-lay burial in soft soils, and in a more limited capacity, the use of mechanical trenching for pre-lay trenching, simultaneous lay and buy, and post-lay burial in areas more challenging for cable burial. As the noise levels generated from cable laying and installation work are low, the potential for take of marine mammals to result is discountable. Atlantic Shores is not requesting and NMFS is not proposing to authorize take associated with cable laying activities. Therefore, cable laying activities are not analyzed further in this document.

Site Preparation and Scour Protection

For export cable installation, site preparation typically includes required sand bedform leveling, boulder clearance, pre-lay grapnel runs, and a pre-lay survey. Due to the presence of mobile sand bedforms, some dredging may be required prior to cable laying. Sand bedform leveling may include the removal of tops of sand bedforms and is typically undertaken where cable exposure is predicted over the lifetime of a project due to seabed mobility. This facilitates cable burial below the reference seabed. Alternatively, sand bedform removal may be undertaken where slopes become greater than approximately 10 degrees (17.6 percent), which could cause instability to the burial tool. If necessary to remove sand bedforms, Atlantic Shores will clear the area using subsea excavation methods. The work could be undertaken by traditional dredging methods such as a trailing suction hopper. Controlled flow excavation may be used to induce water currents to force the seabed into suspension, where it would otherwise be directed to eventually settle (Atlantic Shores, 2021). A route clearance plow may be used to push sand aside and clear the way for cable installation. In areas of hard or rocky seabed substrate, cutterhead dredging may be used in place of the trailing suction hopper dredge. This method involves the use of a larger drill and may be necessary along the ECCs. Backhoe dredging may be used in shallow, nearshore areas where only small amounts of material need to be removed. This equipment operates in a similar way to an onshore backhoe excavator yet is mounted on a small barge (Atlantic Shores, 2021).

Boulder clearance may also be required in targeted locations to clear boulders along the ECCs, inter-array cable routes, and/or foundations prior to installation. Boulder removal can be performed using a combination of methods to optimize clearance of boulder debris of varying size and frequency. Boulder clearance trials are normally performed prior to wide-scale seafloor preparation activities to evaluate efficacy of boulder clearing techniques. If boulders are encountered during installation activities, Atlantic Shores would move them from the ECCs using subsea grabs as the presence of boulders is expected to be minimal and this type of technique has minimal impacts on the seafloor. A boulder grab involves a grab most likely deployed from a dynamic positioning offshore support vessel being lowered to the seabed, over the targeted boulder. Once “grabbed,” the boulder is relocated away from the cable route and/or foundation location. A displacement plow may be used if more boulders than expected are encountered. This type of plow has a simple Y-shaped design and clears an approximately 10-m wide corridor. The plow is towed along the seafloor by a vessel and displaces boulders along a clearance path as it passes over the seabed surface (Atlantic Shores, 2021). The size of boulders that can be relocated is dependent on a number of factors including the boulder weight, dimensions, embedment, density and ground conditions. Typically, boulders with dimensions less than 2.5 m (8 ft) can be relocated with standard tools and equipment.

Additionally, pre-lay grapnel runs may be undertaken to remove any seafloor debris along the ECCs. A specialized vessel will tow an approximately 1-m wide grapnel train consisting of a series of hooks designed to snag debris. Tension measurements on the grapnel train towing rope will indicate whether the hooks have caught debris. Atlantic Shores plans to make three passes with the grapnel train along each cable alignment.

Atlantic Shores would conduct pre-lay surveys along the final planned cable alignments prior to cable installation. The purpose of these surveys would be to confirm seabed morphology and bathymetry and to detect any objects that may impact the future infrastructure. Multi-beam echosounders would be used to survey a 20-m (65.6-ft) wide corridor centered on the cable alignments to examine the total width of the seabed area to be disturbed by cable installation activities (Atlantic Shores, 2021).

Atlantic Shores would also deposit rock around each foundation as scour protection. Installation of the rock would be conducted from a fallpipe vessel using a pipe that extends to just above the seafloor to deposit rock contained in the vessel's hopper in a controlled manner. Scour protection placement would occur prior to and/or after foundation installation.

NMFS does not expect scour protection placement or site preparation work, including boulder removal, sand leveling ( i.e., dredging) pre-lay grapnel runs, and pre-lay surveys, to generate noise levels that would cause take of marine mammals. Dredging, bedform leveling, and boulder clearance is expected to be extremely localized at any given time, and NMFS expects that any marine mammals would not be exposed at levels or durations likely to disrupt behavioral patterns ( i.e., migrating, foraging, calving, etc.). Therefore, the potential for take of marine mammals to result from these activities is so low as to be discountable. Atlantic Shores did not request and NMFS is not proposing to authorize any takes associated with seabed preparation activities; therefore, they are not analyzed further in this document.

Vessel Operation

During construction of the project, Atlantic Shores estimates that approximately 550 to 2,050 vessel round trips to the Lease Area will occur annually during the projects' operations, which is an average of two to six vessel trips per day in support of both Project 1 and 2 (COP Volume 1 section 5.6). Atlantic Shores expects up to 51 vessels to be used during construction, though a maximum of 16 vessels are expected to operate at one time for a given construction activity. Construction vessels would make an estimated 1,745 trips to the Project Area, including trips from the future New Jersey Wind Port, Paulsboro Marine Terminal, and Repauno Port and Rail Terminal in New Jersey; Portsmouth Marine Terminal in Virginia; and the Port of Corpus Christi in Texas. Atlantic Shores generally expects 5 to 16 maintenance vessels to operate at a given time, though up to 22 vessels may be required in some repair scenarios. Maintenance vessels would make an estimated 1,861 trips to the Project Area, the majority of which would originate from the O&M facility in Atlantic City, with a smaller number originating from the New Jersey Wind Port (DEIS Section 3.6.6).

Atlantic Shores plans that their vessel usage will be divided into different campaigns, including: foundation installation, scour protection installation, OSS installation, WTG installation, inter-array cable installation, inter-link cable installation (if needed), and export cable installation. When performing the specific construction task, the vessels would either anchor, jack-up, or maintain their position using dynamic positioning systems, where a continually adjusting propulsion system keeps the vessel in a single location.

Many of these vessels will remain in the Wind Farm Area or ECC for days or weeks at a time, potentially making only infrequent trips to port for bunkering and provisioning, as needed. The actual number of vessels involved in the project at one time is highly dependent on the project's final schedule, the final design of the project's components, and the logistics needed to ensure compliance with the Jones Act, a Federal law that regulates maritime commerce in the United States. Table 3 below shows the number of vessels and the number of vessel trips anticipated during construction activities related to Atlantic Shores South.

Atlantic Shores estimates that up to 37 round trips, monthly, from various ports would be necessary associated with the installation of the WTG and OSS foundations, topside construction associated with WTGs and OSSs, and the necessary scour protection. They further estimate that about 19 monthly round trips would be needed from the port in Atlantic City, up to 17 would be needed from the New Jersey Wind port, and a single monthly round trip would occur from European ports. Where a tug and barge combination would be used, a single vessel trip is assumed from the joint approach as these two vessels would be used conjointly.

While marine mammals are known to respond to vessel noise and the presence of vessels in different ways, we do not expect Atlantic Shores' vessel operations to result in the take of marine mammals. As existing vessel traffic in the vicinity of the Project Area off of New Jersey is relatively high, we expect that marine mammals in the area are likely somewhat habituated to vessel noise. As part of various construction related activities, including cable laying and construction material delivery, dynamic positioning thrusters may be utilized to hold vessels in position or move slowly. Sound produced through use of dynamic positioning thrusters is similar to that produced by transiting vessels, in that dynamic positioning thrusters are typically operated either in a similarly predictable manner or used for short durations around stationary activities. Sound produced by dynamic positioning thrusters would be preceded by, and associated with, sound from ongoing vessel noise and would be similar in nature; thus, any marine mammals in the vicinity of the activity would be aware of the vessel's presence, further reducing the potential for startle or flight responses on the part of marine mammals. Accordingly, noise from construction-related vessel activity, including the use of dynamic positioning thrusters, is not expected to result in take of marine mammals. In addition, any construction vessels would be stationary for significant periods of time when on-site and any large vessels would travel to and from the site at relatively low speeds. Project-related vessels would be required to adhere to several mitigation measures designed to avoid vessel strikes; these measures are described further below (see the Proposed Mitigation section). Vessel strikes are neither anticipated nor authorized. Atlantic Shores did not request, and NMFS does not propose to authorize, take associated with vessel activity. However, NMFS acknowledges the aggregate impacts of Atlantic Shores South's vessel operations on the acoustic habitat of marine mammals and has considered it in the analysis and preliminary determinations contained herein.

Helicopter Usage

Atlantic Shores may supplement vessel-based transport with helicopters to transfer crew to and from the shore and the Lease Area. Crew transport via helicopter may be utilized during offshore construction, commissioning, and testing phases as well as during maintenance of the WTGs (Atlantic Shores, 2021). Helicopters could be used when rapid-response operations and maintenance (O&M) activities are needed or when poor weather limits the use of crew transport vessels. Helicopters would be based within a reasonable distance of the project at a general aviation airport (COP Volume 1 section 5.6). The most intense helicopter activity would occur during construction phases and mostly likely during shift changes. Atlantic Shores does not currently anticipate installing helicopter pads on the OSSs, though this feature may be added depending on the O&M strategy employed. If a helicopter pad is installed, it would be designed to support a U.S. Coast Guard helicopter, including appropriate lighting and marking as required (COP Volume 1 section 5.5; DEIS section 2).

In addition, fixed wing aircraft may be used to support environmental monitoring and mitigation efforts (Atlantic Shores, 2021). Aircraft usage would align with the best practices from regulators when determining routes and altitudes for travel. Helicopters and fixed wing aircraft produce sounds that can be audible to marine mammals; however, most sound energy from aircraft reflects off the air-water interface as only sound radiated downward within a 26-degree cone penetrates below the surface water (Urick, 1972).

Due to the intermittent nature and the small area potentially ensonified by this sound source for a very limited duration, Atlantic Shores did not request, and NMFS is not proposing to authorize, take of marine mammals incidental to helicopter and fixed wing aircraft flights; therefore, these activities will not be discussed further in this proposed action.

Fisheries and Benthic Monitoring

Fisheries and benthic monitoring surveys have been designed in accordance with recommendations set forth by the Responsible Offshore Science Alliance (ROSA) Offshore Wind Project Monitoring Framework and Guidelines ( https://www.rosascience.org/offshore-wind-and-fisheries-resources/; ROSA, 2021). The purpose of the surveys are to document environmental conditions relevant to fisheries in the Project Area throughout the construction and operation phases of the proposed project. Atlantic Shores would conduct demersal otter trawl surveys, ventless trap surveys, and hydraulic clam dredge surveys to enhance existing data for specific benthic and pelagic species of concern. The demersal otter trawl surveys would follow methodology based upon the Northeast Monitoring and Assessment Program (NEAMAP) annual trawl surveys, throughout all four seasons to monitor fish and mega-invertebrate communities. The trawl net would be a four-seam, three bridle, 400 centimeter (cm; 157.48 inch (in)) x 12 cm (4.7 in) net with a cookie sweep and 1 in (2.54 cm) knotless liner in the cod end. The fishing circle would be 400 meshes of 12 cm (4.72 in), 4 millimeter (mm; 0.157 in) braided polyethylene twine (4,800 cm (1889.76 in) fishing circle). The total headrope length, including extension chains, hammerlocks, shackles, and combination cable would be 24.6 m (80.7 ft) long, with extension cables fully slacked out while fishing. Sixty 20.3 cm (8 in) orange center-hole floats would run the length of the headrope. The upper and lower wing ends would be made of stainless-steel combination cable and measure 552 cm (217.3 in) and 459 cm (180.7 in) respectively. The total footrope length including hammerlocks, shackles, and extension wires would be approximately 27 m (88.6 ft) long. The doors would be Thyboron type IV, 167.64 cm (425.8 in) otter trawl doors with 2.25 meters squared (m² ; 24.2 feet square (ft² )) area. A Netmind digital trawl net monitoring system would be incorporated with sensors measuring wing spread, vertical net opening, bottom contact, and a catch sensor in the cod end to trip at approximately 5,000 pounds (lbs; 2,268 kilograms (kg)). Prior to sampling, salinity, temperature, and dissolved oxygen would be measured during a cast to the seafloor with an appropriate oceanographic probe. Sampling would only occur between 30 minutes after sunrise and 30 minutes before sunset. Oceanographic conditions would be recorded at each station before beginning trawl. The tow cable would be deployed to a length of at least 3 times the water column depth. The tow duration would be 20 minutes at a speed of approximately 3 kn (3.45 mph), with the towpath being regularly logged. Once onboard, the catch would be dumped and sorted by species into buckets and baskets unless the tow is deemed a failure. Demersal otter trawl surveys would be conducted during preconstruction and construction years as well as for 3 years post construction.

The ventless trap surveys, or fish pot surveys, would follow survey design adapted from a Rutgers University and New Jersey Department of Environmental Protection (NJDEP) trap survey of artificial reefs offshore of New Jersey (Jensen et al., 2018). The purpose of the trap surveys would be to monitor the presence and size of dominant structure-associated species. Unbaited ventless traps (110.5 cm x 56 cm x 38 cm (43.5 in x 22 in x 15 in)) would be deployed in a trawl attached to a groundline. Each trap would be affixed with a temperature logger and a camera facing outward above the entrance. The groundline on each trap would serve to prevent gear loss and protected species entanglement. Trap surveys would be conducted during all four seasons during preconstruction and construction phases as well as for 3 years post construction. Once traps are set, they would soak for two periods of 5–7 days, depending upon weather. All gear would be removed from the water in between surveys.

Hydraulic clam dredge surveys would use a dredge similar to the NJDEP surf clam survey gear and follow a NMFS Northeast Fisheries Science Center (NEFSC) clam dredge survey methodology (Atlantic Shores, 2023). The purpose of the clam dredge survey would be to detect significant changes in the presence and size of ocean quahogs and Atlantic surf clams from cumulative project effects. Dredge surveys would take place during the summer during preconstruction and construction phases as well as for 3 years post construction. More information about Atlantic Shores' fishery and benthic monitoring surveys can be found in the Atlantic Shores Fisheries Monitoring Plan, Appendix II–K found on our website https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores.

In addition to the above mentioned fishery monitoring surveys, Atlantic Shores would also partner with Rutgers University to conduct a multi-phase modeling study to gain a better understanding of how Mid-Atlantic wind farms and climate change may influence the distribution and abundance of surf clams (Atlantic Shores, 2023). This study builds off an existing simulation of the surf clam fishery in the Mid-Atlantic Bight. The simulation, Spatially-explicit Ecological agent-based Fisheries and Economic Simulator (SEFES), currently models the interactions between surf stock biology, fishery captain and fleet behavior, Federal management decisions, fishery economics, port structure, and wind farm development. Atlantic Shores will partner with Rutgers University to expand the capabilities of SEFES to assess fisheries and wind development activities from present day to 30 years into the future and run scenarios that factor in the presence of the proposed project. Atlantic Shores would also partner with Stockton University to study the ecological succession of newly submerged artificial reefs off New Jersey through the use of acoustic and video observation. Surveys would be conducted using side scan sonar, multibeam echosounder, and direct observation via a remotely operated vehicle (ROV) to collect data for 3–D mapping of artificial reef structures. Maps would provide base layers to overlay biological assessments to better understand ecological succession of newly submerged reef structures. Atlantic Shores does not anticipate, and NMFS is not proposing to authorize, take of marine mammals incidental to these activities and they are not discussed further in this document.

In general, trap and trawl surveys have the potential to result in the take of marine mammals given there is a risk of entanglement. However, Atlantic Shores would implement mitigation and monitoring measures to avoid taking marine mammals, including, but not limited to, use of bycatch reduction gear such as ropeless gear for trap surveys, monitoring for marine mammals before and during trawling activities, not deploying or pulling trawl gear in certain circumstances, limiting tow times, fully repairing nets, and reporting protected species interactions to the NMFS Greater Atlantic Region Field Office (GARFO). All trap and trawl surveys would also comply with take reduction team regulations for Atlantic large whales, harbor porpoises, and bottlenose dolphins, and Atlantic Trawl Take Reduction Strategy measures to reduce the potential for interactions between small cetaceans and trawl (bottom and mid-water) gear (Atlantic Shores, 2023). A full description of mitigation measures can be found in the Proposed Mitigation section.

With the implementation of these measures, Atlantic Shores does not anticipate, and NMFS is not proposing to authorize, take of marine mammals incidental to research trap and trawl surveys. Given no take is anticipated from these surveys, impacts from fishery surveys will not be discussed further in this document (with the exception of the description of measures in the Proposed Mitigation section).

Description of Marine Mammals in the Geographic Area of Specified Activities

Thirty-eight marine mammal species under NMFS' jurisdiction have geographic ranges within the western North Atlantic OCS (Hayes et al., 2022). However, for reasons described below, Atlantic Shores has requested, and NMFS proposes to authorize, take of only 16 species (comprising 17 stocks) of marine mammals. Sections 3 and 4 of Atlantic Shores' ITA application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history of the potentially affected species (JASCO, 2022). NMFS fully considered all of this information, and we refer the reader to these descriptions in the application instead of reprinting the information. Additional information regarding population trends and threats may be found in NMFS's Stock Assessment Reports (SARs), https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments ), and more general information about these species ( e.g., physical and behavioral descriptions) may be found on NMFS's website ( https://www.fisheries.noaa.gov/find-species ).

Of the 38 marine mammal species and/or stocks with geographic ranges that include the Project Area ( i.e., found in the coastal and offshore waters of New Jersey), 22 are not expected to be present or are considered rare or unexpected in the Project Area based on sighting and distribution data (see Table 11 in Atlantic Shores' ITA application); they are, therefore, not discussed further beyond the explanation provided here. Specifically, the following cetacean species are known to occur off of New Jersey but are not expected to occur in the Project Area due to the location of preferred habitat outside the Lease Area and ECCs, based on the best available information: Blue whale ( Balaenoptera musculus), Cuvier's beaked whale ( Ziphius cavirostris), four species of Mesoplodont beaked whales ( Mesoplodon densitostris, M. europaeus, M. mirus, and M. bidens), clymene dolphin ( Stenella clymene), false killer whale ( Pseudorca crassidens), Fraser's dolphin ( Lagenodelphis hosei), killer whale ( Orcinus orca), melon-headed whale ( Peponocephala electra), pantropical spotted dolphin ( Stenella attenuata), pygmy killer whale ( Feresa attenuata), rough-toothed dolphin ( Steno bredanensis), spinner dolphin ( Stenella longirostris), striped dolphin ( Stenella coeruleoalba), white-beaked dolphin ( Lagenorhynchus albirostris), Northern bottlenose whale ( Hyperoodon ampullatus), dwarf sperm whale ( Kogia sima), and the pygmy sperm whale ( Kogia breviceps). Two species of phocid pinnipeds are also uncommon in the Project Area, including: harp seals ( Pagophilus groenlandica) and hooded seals ( Cystophora cristata).

In addition, the Florida manatees ( Trichechus manatus; a sub-species of the West Indian manatee) has been previously documented as an occasional visitor to the Mid-Atlantic region during summer months (Morgan et al., 2002; Cummings et al., 2014). However, as manatees are managed solely under the jurisdiction of the U.S. Fish and Wildlife Service (USFWS), they are not considered or discussed further in this document.

Table 4 lists all species and stocks for which take is expected and proposed to be authorized for this action and summarizes information related to the population or stock, including regulatory status under the MMPA and Endangered Species Act (ESA) and potential biological removal (PBR), where known. PBR is defined as “the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population” (16 U.S.C. 1362(20)). While no mortality is anticipated or proposed to be authorized, PBR and annual serious injury and mortality from anthropogenic sources are included here as gross indicators of the status of the species and other threats.

Marine mammal abundance estimates presented in this document represent the total number of individuals that make up a given stock or the total number estimated within a particular study or survey area. NMFS' stock abundance estimates for most species represent the total estimate of individuals within the geographic area, if known, that comprises that stock. For some species, this geographic area may extend beyond U.S. waters. All managed stocks in this region are assessed in NMFS's U.S. Atlantic and Gulf of Mexico SARs. All values presented in Table 4 are the most recent available data at the time of publication, which can be found in NMFS' final2022 SARs (Hayes et al., 2023) available online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

As indicated above, all 16 species and 17 stocks in Table 4 temporally and spatially co-occur with the activity to the degree that take is reasonably likely to occur. Four of the marine mammal species for which take is requested are listed as threatened or endangered under the ESA, including North Atlantic right, fin, sei, and sperm whales.

In addition to what is included in Sections 3 and 4 of Atlantic Shores' ITA application ( https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores ), the SARs ( https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments ), and NMFS' website ( https://www.fisheries.noaa.gov/species-directory/marine-mammals ), we provide further detail below informing the baseline for select species ( e.g., information regarding current UMEs and known important habitat areas, such as Biologically Important Areas (BIAs) (Van Parijs, 2015). There are no ESA-designated critical habitats for any species within the Project Area ( https://www.fisheries.noaa.gov/resource/map/national-esa-critical-habitat-mapper ).

Under the MMPA, a UME is defined as “a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response” (16 U.S.C. 1421h(6)). As of May 2023, five UMEs are active. Four of these UMEs are occurring along the U.S. Atlantic coast for various marine mammal species. Of these, the most relevant to the Project Area are the North Atlantic right whale, humpback whale, and harbor and gray seal UMEs given the prevalence of these species in the Project Area. More information on UMEs, including all active, closed, or pending, can be found on NMFS' website at https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

Below, we include information for a subset of the species that presently have an active or recently closed UME occurring along the Atlantic coast or for which there is information available related to areas of biological significance. For the majority of species potentially present in the specific geographic region, NMFS has designated only a single generic stock ( e.g., “western North Atlantic”) for management purposes. This includes the “Canadian east coast” stock of minke whales, which includes all minke whales found in U.S. waters and is also a generic stock for management purposes. For humpback and sei whales, NMFS defines stocks on the basis of feeding locations ( i.e., Gulf of Maine and Nova Scotia, respectively). However, references to humpback whales and sei whales in this document refer to any individuals of the species that are found in the project area. Any areas of known biological importance (including the BIAs identified in LaBrecque et al., 2015) that overlap spatially (or are adjacent) with the project area are addressed in the species sections below.

North Atlantic Right Whale

The North Atlantic right whale has been listed as Endangered since the ESA's enactment in 1973. The species was recently uplisted from Endangered to Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Cooke, 2020). The uplisting was due to a decrease in population size (Pace et al., 2017), an increase in vessel strikes and entanglements in fixed fishing gear (Daoust et al., 2017; Davis & Brillant, 2019; Knowlton et al., 2012; Knowlton et al., 2022; Moore et al., 2021; Sharp et al., 2019), and a decrease in birth rate (Pettis et al., 2022; Reed et al., 2022). The Western Atlantic stock is considered depleted under the MMPA (Hayes et al., 2022). There is a recovery plan (NMFS, 2005) for the North Atlantic right whale, and NMFS completed 5-year reviews of the species in 2012, 2017, and 2022 which concluded no change to the listing status is warranted.

Designated by NMFS as a Species in the Spotlight, the North Atlantic right whale is considered among the species with the greatest risk of extinction in the near future ( https://www.fisheries.noaa.gov/topic/endangered-species-conservation/species-in-the-spotlight ).

The North Atlantic right whale population had only a 2.8 percent recovery rate between 1990 and 2011 and an overall abundance decline of 23.5 percent from 2011–2019 (Hayes et al., 2022). Since 2010, the North Atlantic right whale population has been in decline (Pace et al., 2017; Pace et al., 2021), with a 40 percent decrease in calving rate (Kraus et al., 2016; Moore et al., 2021). North Atlantic right whale calving rates dropped from 2017 to 2020 with zero births recorded during the 2017–2018 season. The 2020–2021 calving season had the first substantial calving increase in 5 years with 20 calves born followed by 15 calves during the 2021–2022 calving season. However, mortalities continue to outpace births, and best estimates indicate fewer than 70 reproductively active females remain in the population.

Critical habitat for North Atlantic right whales is not present in the project area. However, the project area both spatially and temporally overlaps a portion of the migratory corridor BIA within which North Atlantic right whales migrate south to calving grounds generally in November and December, followed by a northward migration into feeding areas north of the Project Area in March and April (LaBrecque et al., 2015; Van Parijs et al., 2015). The Project Area does not overlap any North Atlantic right whale feeding BIAs.

NMFS' regulations at 50 CFR 224.105 designated Seasonal Management Areas (SMAs) for North Atlantic right whales in 2008 (73 FR 60173, October 10, 2008). SMAs were developed to reduce the threat of collisions between ships and North Atlantic right whales around their migratory route and calving grounds. There is an SMA for the Ports of New York/New Jersey near the proposed Project Area; this SMA is currently active from November 1 through April 30 of each year and may be used by North Atlantic right whales for feeding (although to a lesser extent than the area to the north near Nantucket Shoals) and/or migrating. As noted above, independent of the action considered here, NMFS is proposing changes to the North Atlantic right whale speed rule (87 FR 46921, August 1, 2022). Due to the current status of North Atlantic right whales and the spatial proximity overlap of the proposed project with areas of biological significance, ( i.e., a migratory corridor, SMA), the potential impacts of the proposed project on North Atlantic right whales warrant particular attention.

North Atlantic right whale presence in the Project Area is predominately seasonal. However, year-round occurrence is documented (Davis et al., 2017). Abundance is highest in winter with irregular occurrence during summer months and similar occurrence rates in spring and fall (O'Brien et al., 2022; Quintana-Rizzo et al., 2021; Estabrook et al., 2022). North Atlantic right whale distribution can also be derived from acoustic data. A review of passive acoustic monitoring data from 2004 to 2014 collected throughout the western North Atlantic demonstrated nearly continuous year-round North Atlantic right whale presence across their entire habitat range with a decrease in summer months, including in locations previously thought of as migratory corridors, suggesting that not all of the population undergoes a consistent annual migration (Davis et al., 2017). Observations of these transitions in North Atlantic right whale habitat use, variability in seasonal presence in identified core habitats, and utilization of habitat outside of previously focused survey effort prompted the formation of a NMFS' Expert Working Group, which identified current data collection efforts, data gaps, and provided recommendations for future survey and research efforts (Oleson et al., 2020). Recent research indicates understanding of their movement patterns remains incomplete and not all of the population undergoes a consistent annual migration (Davis et al., 2017; Gowan et al., 2019; Krzystan et al., 2018). Non-calving females may remain in the feeding grounds, during the winter in the years preceding and following the birth of a calf to increase their energy stores (Gowen et al., 2019).

To describe seasonal trends in North Atlantic right whale presence, Estabrook et al. (2022) analyzed North Atlantic right whale acoustic detections collected between 2011–2015 during winter (January through March), spring (April through June), summer (July through September), and autumn (October–December) off Rhode Island and Massachusetts. Winter had the highest presence (75 percent array-days, n=193), and summer had the lowest presence (10 percent array-days, n=27). Spring and autumn were similar, where 45 percent (n=117) and 51 percent (n=121) of the array-days had detections, respectively. Across all years, detections were consistently lowest in August and September. In Massachusetts Bay and Cape Cod Bay, located further north from the Atlantic Shores South Project Area, acoustic detections of North Atlantic right whales increased in more recent years in both the peak season of late winter through early spring and in summer and fall, likely reflecting broad-scale regional habitat changes (Charif et al., 2020). NMFS' Passive Acoustic Cetacean Map (PACM) contains up-to-date acoustic data that contributes to our understanding of when and where specific whales (including North Atlantic right whales), dolphin, and other cetacean species are acoustically detected in the North Atlantic. These data augment the findings of the aforementioned literature.

In late fall ( i.e., November), a portion of the North Atlantic right whale population (including pregnant females) typically departs the feeding grounds in the North Atlantic, moves south along the migratory corridor BIA, including through the Project Area, to North Atlantic right whale calving grounds off Georgia and Florida. However, recent research indicates understanding of their movement patterns remains incomplete and not all of the population undergoes a consistent annual migration (Davis et al., 2017; Gowan et al., 2019; Krzystan et al., 2018). The results of multistate temporary emigration capture-recapture modeling, based on sighting data collected over the past 22 years, indicate that non-calving females may remain in the feeding grounds, during the winter in the years preceding and following the birth of a calf to increase their energy stores (Gowan et al., 2019).

New Jersey waters are a migratory corridor in the spring and early winter for North Atlantic right whales; these waters are not known foraging or calving habitat. North Atlantic right whales feed primarily on the copepod, Calanus finmarchicus, a species whose availability and distribution has changed both spatially and temporally over the last decade due to an oceanographic regime shift that has been ultimately linked to climate change (Meyer-Gutbrod et al., 2021; Record et al., 2019; Sorochan et al., 2019). This distribution change in prey availability has led to shifts in North Atlantic right whale habitat-use patterns within the region over the same time period (Davis et al., 2020; Meyer-Gutbrod et al., 2022; Quintana-Rizzo et al., 2021; O'Brien et al., 2022). Since 2010, North Atlantic right whales have reduced their use of foraging habitats in the Great South Channel and Bay of Fundy while increasing their use of habitat within Cape Cod Bay as well as a region south of Martha's Vineyard and Nantucket Islands (Stone et al., 2017; Mayo et al., 2018; Ganley et al., 2019; Record et al., 2019; Meyer-Gutbrod et al., 2021). While the Project Area is south of Martha's Vineyard and Nantucket Island, these foraging habitats are all located several hundred kilometers north of the Project Area.

In August 2023, NMFS released its final 2022 SARs, which updated the population estimate (N_best) of North Atlantic right whales from 368 to 338 individuals and the annual M/SI value from 8.1 to 31.2 due to the addition of estimated undetected mortality and serious injury, as described above, which had not been previously included in the SAR. The population estimate is slightly lower than the North Atlantic Right Whale Consortium's 2022 Report Card, which identifies the population estimate as 340 individuals (Pettis et al., 2023). Elevated North Atlantic right whale mortalities have occurred since June 7, 2017, along the U.S. and Canadian coast, with the leading category for the cause of death for this UME determined to be “human interaction,” specifically from entanglements or vessel strikes. Since publication of the proposed rule, the number of animals considered part of the UME has increased. As of August 16, 2023, there have been 36 confirmed mortalities (dead, stranded, or floaters), 0 pending mortalities, and 34 seriously injured free-swimming whales for a total of 70 whales. As of October 14, 2022, the UME also considers animals (n=45) with sub-lethal injury or illness (called “morbidity”) bringing the total number of whales in the UME to 115. More information about the North Atlantic right whale UME is available online at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-north-atlantic-right-whale-unusual-mortality-event.

Humpback Whale

Humpback whales were listed as endangered under the Endangered Species Conservation Act (ESCA) in June 1970. In 1973, the ESA replaced the ESCA, and humpbacks continued to be listed as endangered. On September 8, 2016, NMFS divided the species into 14 distinct population segments (DPS), removed the species-level listing, and, in its place, listed four DPSs as endangered and one DPS as threatened (81 FR 62259, September 8, 2016). The remaining nine DPSs were not listed. The West Indies DPS, which is not listed under the ESA, is the only DPS of humpback whales that is expected to occur in the project area. Bettridge et al. (2015) estimated the size of the West Indies DPS population at 12,312 (95 percent confidence interval (CI) 8,688–15,954) whales in 2004–05, which is consistent with previous population estimates of approximately 10,000–11,000 whales (Stevick et al., 2003; Smith et al., 1999) and the increasing trend for the West Indies DPS (Bettridge et al., 2015).

Humpback whales are migratory off coastal New Jersey, moving seasonally between northern feeding grounds in New England and southern calving grounds in the West Indies (Hayes et al., 2022). Although sightings of humpback whales used to occur infrequently off New Jersey, they are now common along the Mid-Atlantic States during the winter when most humpback whales are at the breeding grounds (Swingle et al., 1993; Barco et al., 2002; Brown et al., 2022). This shift is also supported by passive acoustic monitoring data ( e.g., Davis et al., 2020). Recently, Brown et al. (2022) investigated site fidelity, population composition and demographics of individual whales in the New York Bight apex (which includes New Jersey waters and found that although mean occurrence was low (2.5 days), mean occupancy was 37.6 days, and 31.3 percent of whales returned from 1 year to the next. The majority of whales were seen during summer (July to September, 62.5 percent), followed by autumn (October to December, 23.5 percent) and spring (April to June, 13.9 percent). When data were available to evaluate age, most individuals were either confirmed or suspected juveniles, including 4 whales known to be 2 to 4 years old based on known birth year, and 13 whales with sighting histories of 2 years or less on primary feeding grounds. Three individuals were considered adults based on North Atlantic sighting records. The young age structure in the nearshore waters of the New York Bight apex is consistent with other literature (Stepanuk et al., 2021; Swingle et al., 1993; Barco et al., 2002). It remains to be determined whether humpback whales in the New York Bight apex represent a northern expansion of individuals that had wintered off Virginia, a southern expansion of individuals from the adjacent Gulf of Maine, or is the result of another phenomenon.

In addition to a migratory pathway, the mid-Atlantic region also represents a supplemental winter feeding ground for juveniles and mature whales (Barco et al., 2002). Records of humpback whales off the U.S. mid-Atlantic coast (New Jersey south to North Carolina) suggest that these waters are used as a winter feeding ground from December through March (Mallette et al., 2017; Barco et al., 2002; LaBrecque et al., 2015) and represent important habitat for juveniles, in particular (Swingle et al., 1993; Wiley et al., 1995). Humpback whales have been observed feeding off the coast of New Jersey (Swingle et al., 1993; Geo-Marine, Inc., 2010; Whitt et al., 2015). A sighting of a cow-calf pair seen north of the study area boundary supports the theory that the nearshore waters off of New Jersey may provide important feeding and nursery habitats for humpback whales (Geo-Marine, 2010). In addition, recent research by King et al. (2021) has demonstrated a higher occurrence and foraging use of the New York Bight area by humpback whales than previously known. According to Roberts et al. (2023) density models, the highest density of humpback whales in the vicinity of the proposed Project Area is expected to occur during the month of April (0.25–0.40 individuals/100 km² ).

The Project Area does not overlap any ESA-designated critical habitat, BIAs, or other important areas for the humpback whales. A humpback whale feeding BIA extends throughout the Gulf of Maine, Stellwagen Bank, and Great South Channel from May through December, annually (LaBrecque et al., 2015). However, this BIA is located further north of, and thus does not overlap, the Project Area.

Since January 2016, elevated humpback whale mortalities have occurred along the Atlantic coast from Maine to Florida. This event was declared a UME in April 2017. Partial or full necropsy examinations have been conducted on approximately half of the 204 known cases (as of August 16, 2023). Of the whales examined (approximately 90), about 40 percent had evidence of human interaction, either vessel strike or entanglement (refer to https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast ). While a portion of the whales have shown evidence of pre-mortem vessel strike, this finding is not consistent across all whales examined and more research is needed. NOAA is consulting with researchers that are conducting studies on the humpback whale populations, and these efforts may provide information on changes in whale distribution and habitat use that could provide additional insight into how these vessel interactions occurred. More information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast.

Since December 1, 2022, the number of humpback strandings along the mid-Atlantic coast, including New Jersey, has been elevated. In some cases, the cause of death is not yet known. In others, vessel strike has been deemed the cause of death. As the humpback whale population has grown, they are seen more often in the Mid-Atlantic. These whales may be following their prey (small fish) which are reportedly close to shore in the winter. These prey also attract fish that are of interest to recreational and commercial fishermen. This increases the number of boats and fishing gear in these areas. More whales in the water in areas traveled by boats of all sizes increases the risk of vessel strikes. Vessel strikes and entanglement in fishing gear are the greatest human threats to large whales.

Minke Whale

Minke whales are common and widely distributed throughout the U.S. Atlantic Exclusive Economic Zone (EEZ) (CETAP, 1982; Hayes et al., 2022), although their distribution has a strong seasonal component. Individuals have often been detected acoustically in shelf waters from spring to fall and more often detected in deeper offshore waters from winter to spring (Risch et al., 2013). Minke whales are abundant in New England waters from May through September (Pittman et al., 2006; Waring et al., 2014), yet largely absent from these areas during the winter, suggesting the possible existence of a migratory corridor (LaBrecque et al., 2015). A migratory route for minke whales transiting between northern feeding grounds and southern breeding areas may exist to the north and east of the proposed Project Area as minke whales may track warmer waters along the continental shelf while migrating (Risch et al., 2014). Overall, minke whale use of the Project Area is likely highest during winter and spring months when foundation installation would not be occurring. Density data from Roberts et al. (2023) confirm that the highest average density of minke whales in the vicinity of the Project Area occurs in April (0.63–1.00 individuals/100 km² ). Construction is planned for May through December.

There are two minke whale feeding BIAs identified in the southern and southwestern section of the Gulf of Maine, including Georges Bank, the Great South Channel, Cape Cod Bay and Massachusetts Bay, Stellwagen Bank, Cape Anne, and Jeffreys Ledge from March through November, annually (LeBrecque et al., 2015). However, these BIAs do not overlap the Project Area as they are located approximately 378.7 km (235.3 mi) away. No mating or calving grounds have been identified along the U.S. Atlantic coast (LaBrecque et al., 2015).

Since January 2017, a UME has been declared based on elevated minke whale mortalities detected along the Atlantic coast from Maine through South Carolina. As of August 16, 2023, a total of 156 minke whales have stranded during this UME. Full or partial necropsy examinations were conducted on more than 60 percent of the whales. Preliminary findings have shown evidence of human interactions or infectious disease in several of the whales, but these findings are not consistent across all of the whales examined, so more research is needed. This UME has been declared non-active and is pending closure. More information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-minke-whale-unusual-mortality-event-along-atlantic-coast.

Phocid Seals

Since June 2022, elevated numbers of harbor seal and gray seal mortalities have occurred across the southern and central coast of Maine. This event was declared a UME in July 2022. Preliminary testing of samples has found some harbor and gray seals are positive for highly pathogenic avian influenza. While the UME is not occurring in the Project Area, the populations affected by the UME are the same as those potentially affected by the Project. However, due to the two states being approximately 352 km (219 mi) apart, by water (from the most northern point of New Jersey to the most southern point of Maine), NMFS does not expect that this UME would be further conflated by the activities related to the Project. Information on this UME is available online at: https://www.fisheries.noaa.gov/2022-2023-pinniped-unusual-mortality-event-along-maine-coast.

The above event was preceded by a different UME, occurring from 2018–2020 (closure of the 2018–2020 UME is pending). Beginning in July 2018, elevated numbers of harbor seal and gray seal mortalities occurred across Maine, New Hampshire, and Massachusetts. Additionally, stranded seals have shown clinical signs as far south as Virginia, although not in elevated numbers, therefore the UME investigation encompassed all seal strandings from Maine to Virginia. A total of 3,152 reported strandings (of all species) occurred from July 1, 2018, through March 13, 2020. Full or partial necropsy examinations have been conducted on some of the seals and samples have been collected for testing. Based on tests conducted thus far, the main pathogen found in the seals is phocine distemper virus. NMFS is performing additional testing to identify any other factors that may be involved in this UME. Information on this UME is available online at https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.

Marine Mammal Hearing

Hearing is the most important sensory modality for marine mammals underwater, and exposure to anthropogenic sound can have deleterious effects. To appropriately assess the potential effects of exposure to sound, it is necessary to understand the frequency ranges marine mammals are able to hear. Current data indicate that not all marine mammal species have equal hearing capabilities ( e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. (2007) recommended that marine mammals be divided into functional hearing groups based on directly measured or estimated hearing ranges on the basis of available behavioral response data, audiograms derived using auditory evoked potential techniques, anatomical modeling, and other data. Note that no direct measurements of hearing ability have been successfully completed for mysticetes ( i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described generalized hearing ranges for these marine mammal hearing groups. Generalized hearing ranges were chosen based on the approximately 65 decibel (dB) threshold from the normalized composite audiograms, with the exception for lower limits for low-frequency cetaceans where the lower bound was deemed to be biologically implausible and the lower bound from Southall et al. (2007) retained. Marine mammal hearing groups and their associated hearing ranges are provided in Table 5.

The pinniped functional hearing group was modified from Southall et al. (2007) on the basis of data indicating that phocid species have consistently demonstrated an extended frequency range of hearing compared to otariids, especially in the higher frequency range (Hemilä et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 2013). For more detail concerning these groups and associated frequency ranges, please see NMFS (2018) for a review of available information.

NMFS notes that in 2019a, Southall et al. recommended new names for hearing groups that are widely recognized. However, this new hearing group classification does not change the weighting functions or acoustic thresholds ( i.e., the weighting functions and thresholds in Southall et al. (2019a) are identical to NMFS 2018 Revised Technical Guidance). When NMFS updates our Technical Guidance, we will be adopting the updated Southall et al. (2019a) hearing group classification.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

This section includes a summary and discussion of the ways that components of the specified activity may impact marine mammals and their habitat. The Estimated Take section later in this document includes a quantitative analysis of the number of individuals that are expected to be taken by this activity. The Negligible Impact Analysis and Determination section considers the content of this section, the Estimated Take section, and the Proposed Mitigation section, to draw conclusions regarding the likely impacts of these activities on the reproductive success or survivorship of individuals and how those impacts on individuals are likely to impact marine mammal species or stocks. General background information on marine mammal hearing was provided previously (see the Description of Marine Mammals in the Area of the Specified Activities section). Here, the potential effects of sound on marine mammals are discussed.

Atlantic Shores has requested, and NMFS proposes to authorize, the take of marine mammals incidental to the construction activities associated with the Project Area. In their application and Application Update Report, Atlantic Shores presented their analyses of potential impacts to marine mammals from the acoustic sources. NMFS both carefully reviewed the information provided by Atlantic Shores, as well as independently reviewed applicable scientific research and literature and other information to evaluate the potential effects of the project's activities on marine mammals.

The proposed activities would result in the construction and placement of up to 205 permanent foundations to support 200 WTGs, 4 large OSSs, and a single Met Tower. There are a variety of types and degrees of effects to marine mammals, prey species, and habitat that could occur as a result of the project. Below we provide a brief description of the types of sound sources that would be generated by the project, the general impacts from these types of activities, and an analysis of the anticipated impacts on marine mammals from the project, with consideration of the proposed mitigation measures.

Description of Sound Sources

This section contains a brief technical background on sound, on the characteristics of certain sound types, and on metrics used in this proposal inasmuch as the information is relevant to the specified activity and to a discussion of the potential effects of the specified activity on marine mammals found later in this document. For general information on sound and its interaction with the marine environment, please see Au and Hastings (2008); Richardson et al. (1995); Urick (1983) as well as the Discovery of Sound in the Sea (DOSITS) website at https://dosits.org/. Sound is a vibration that travels as an acoustic wave through a medium such as a gas, liquid or solid. Sound waves alternately compress and decompress the medium as the wave travels. These compressions and decompressions are detected as changes in pressure by aquatic life and man-made sound receptors such as hydrophones (underwater microphones). In water, sound waves radiate in a manner similar to ripples on the surface of a pond and may be either directed in a beam (narrow beam or directional sources) or sound beams may radiate in all directions (omnidirectional sources).

Sound travels in water more efficiently than almost any other form of energy, making the use of acoustics ideal for the aquatic environment and its inhabitants. In seawater, sound travels at roughly 1,500 meters per second (m/s). In-air, sound waves travel much more slowly, at about 340 m/s. However, the speed of sound can vary by a small amount based on characteristics of the transmission medium, such as water temperature and salinity. The basic components of a sound wave are frequency, wavelength, velocity, and amplitude. Frequency is the number of pressure waves that pass by a reference point per unit of time and is measured in Hz or cycles per second. Wavelength is the distance between two peaks or corresponding points of a sound wave (length of one cycle). Higher frequency sounds have shorter wavelengths than lower frequency sounds, and typically attenuate (decrease) more rapidly, except in certain cases in shallower water.

The intensity (or amplitude) of sounds are measured in dB, which are a relative unit of measurement that is used to express the ratio of one value of a power or field to another. Decibels are measured on a logarithmic scale, so a small change in dB corresponds to large changes in sound pressure. For example, a 10-dB increase is a 10-fold increase in acoustic power. A 20-dB increase is then a 100-fold increase in power and a 30-dB increase is a 1,000-fold increase in power. However, a ten-fold increase in acoustic power does not mean that the sound is perceived as being 10 times louder. Decibels are a relative unit comparing two pressures, therefore, a reference pressure must always be indicated. For underwater sound, this is 1 microPascal (μPa). For in-air sound, the reference pressure is 20 μPa. The amplitude of a sound can be presented in various ways. However, NMFS typically considers three metrics. In this proposed rule, all decibel levels referenced to 1μPa.

Sound exposure level (SEL) represents the total energy in a stated frequency band over a stated time interval or event, and considers both amplitude and duration of exposure (represented as dB re 1 μPa² -s). SEL is a cumulative metric; it can be accumulated over a single pulse (for pile driving this is often referred to as single-strike SEL; SEL_ss), or calculated over periods containing multiple pulses (SEL_cum). Cumulative SEL represents the total energy accumulated by a receiver over a defined time window or during an event. The SEL metric is useful because it allows sound exposures of different durations to be related to one another in terms of total acoustic energy. The duration of a sound event and the number of pulses, however, should be specified as there is no accepted standard duration over which the summation of energy is measured.

Root mean square (rms) is the quadratic mean sound pressure over the duration of an impulse. Root mean square is calculated by squaring all of the sound amplitudes, averaging the squares, and then taking the square root of the average (Urick, 1983). Root mean square accounts for both positive and negative values; squaring the pressures makes all values positive so that they may be accounted for in the summation of pressure levels (Hastings and Popper, 2005). This measurement is often used in the context of discussing behavioral effects, in part because behavioral effects, which often result from auditory cues, may be better expressed through averaged units than by peak pressures.

Peak sound pressure (also referred to as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous sound pressure measurable in the water at a specified distance from the source, and is represented in the same units as the rms sound pressure. Along with SEL, this metric is used in evaluating the potential for PTS (permanent threshold shift) and TTS (temporary threshold shift).

Sounds can be either impulsive or non-impulsive. The distinction between these two sound types is important because they have differing potential to cause physical effects, particularly with regard to hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see NMFS et al. (2018) and Southall et al. (2007, 2019a) for an in-depth discussion of these concepts. Impulsive sound sources ( e.g., airguns, explosions, gunshots, sonic booms, impact pile driving) produce signals that are brief (typically considered to be less than 1 second), broadband, atonal transients (American National Standards Institute (ANSI), 1986, 2005; Harris, 1998; National Institute for Occupational Safety and Health (NIOSH), 1998; International Organization for Standardization (ISO), 2003) and occur either as isolated events or repeated in some succession. Impulsive sounds are all characterized by a relatively rapid rise from ambient pressure to a maximal pressure value followed by a rapid decay period that may include a period of diminishing, oscillating maximal and minimal pressures, and generally have an increased capacity to induce physical injury as compared with sounds that lack these features. Impulsive sounds are typically intermittent in nature.

Non-impulsive sounds can be tonal, narrowband, or broadband, brief or prolonged, and may be either continuous or intermittent (ANSI, 1995; NIOSH, 1998). Some of these non-impulsive sounds can be transient signals of short duration but without the essential properties of pulses ( e.g., rapid rise time). Examples of non-impulsive sounds include those produced by vessels, aircraft, machinery operations such as drilling or dredging, vibratory pile driving, and active sonar systems. Sounds are also characterized by their temporal component. Continuous sounds are those whose sound pressure level remains above that of the ambient sound with negligibly small fluctuations in level (NIOSH, 1998; ANSI, 2005) while intermittent sounds are defined as sounds with interrupted levels of low or no sound (NIOSH, 1998). NMFS identifies Level B harassment thresholds based on whether a sound is continuous or intermittent.

Even in the absence of sound from the specified activity, the underwater environment is typically loud due to ambient sound, which is defined as environmental background sound levels lacking a single source or point (Richardson et al., 1995). The sound level of a region is defined by the total acoustical energy being generated by known and unknown sources. These sources may include physical ( e.g., wind and waves, earthquakes, ice, atmospheric sound), biological ( e.g., sounds produced by marine mammals, fish, and invertebrates), and anthropogenic ( e.g., vessels, dredging, construction) sound. A number of sources contribute to ambient sound, including wind and waves, which are a main source of naturally occurring ambient sound for frequencies between 200 Hz and 50 kHz (International Council for the Exploration of the Sea (ICES), 1995). In general, ambient sound levels tend to increase with increasing wind speed and wave height. Precipitation can become an important component of total sound at frequencies above 500 Hz and possibly down to 100 Hz during quiet times. Marine mammals can contribute significantly to ambient sound levels as can some fish and snapping shrimp. The frequency band for biological contributions is from approximately 12 Hz to over 100 kHz. Sources of ambient sound related to human activity include transportation (surface vessels), dredging and construction, oil and gas drilling and production, geophysical surveys, sonar, and explosions. Vessel noise typically dominates the total ambient sound for frequencies between 20 and 300 Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz, and if higher frequency sound levels are created, they attenuate rapidly.

The sum of the various natural and anthropogenic sound sources that comprise ambient sound at any given location and time depends not only on the source levels (as determined by current weather conditions and levels of biological and human activity) but also on the ability of sound to propagate through the environment. In turn, sound propagation is dependent on the spatially and temporally varying properties of the water column and sea floor, and is frequency-dependent. As a result of the dependence on a large number of varying factors, ambient sound levels can be expected to vary widely over both coarse and fine spatial and temporal scales. Sound levels at a given frequency and location can vary by 10–20 dB from day to day (Richardson et al., 1995). The result is that, depending on the source type and its intensity, sound from the specified activity may be a negligible addition to the local environment or could form a distinctive signal that may affect marine mammals. Human-generated sound is a significant contributor to the acoustic environment in the project location.

Potential Effects of Underwater Sound on Marine Mammals

Anthropogenic sounds cover a broad range of frequencies and sound levels and can have a range of highly variable impacts on marine life from none or minor to potentially severe responses depending on received levels, duration of exposure, behavioral context, and various other factors. Broadly, underwater sound from active acoustic sources, such as those in the project, can potentially result in one or more of the following: temporary or permanent hearing impairment, non-auditory physical or physiological effects, behavioral disturbance, stress, and masking (Richardson et al., 1995; Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007; Götz et al., 2009). Non-auditory physiological effects or injuries that theoretically might occur in marine mammals exposed to high level underwater sound or as a secondary effect of extreme behavioral reactions ( e.g., change in dive profile as a result of an avoidance reaction) caused by exposure to sound include neurological effects, bubble formation, resonance effects, and other types of organ or tissue damage (Cox et al., 2006; Southall et al., 2007; Zimmer and Tyack, 2007; Tal et al., 2015).

In general, the degree of effect of an acoustic exposure is intrinsically related to the signal characteristics, received level, distance from the source, and duration of the sound exposure, in addition to the contextual factors of the receiver ( e.g., behavioral state at time of exposure, age class, etc.). In general, sudden, high level sounds can cause hearing loss as can longer exposures to lower level sounds. Moreover, any temporary or permanent loss of hearing will occur almost exclusively for noise within an animal's hearing range. We describe below the specific manifestations of acoustic effects that may occur based on the activities proposed by Atlantic Shores.

Richardson et al. (1995) described zones of increasing intensity of effect that might be expected to occur in relation to distance from a source and assuming that the signal is within an animal's hearing range. First (at the greatest distance) is the area within which the acoustic signal would be audible (potentially perceived) to the animal but not strong enough to elicit any overt behavioral or physiological response. The next zone (closer to the receiving animal) corresponds with the area where the signal is audible to the animal and of sufficient intensity to elicit behavioral or physiological responsiveness. The third is a zone within which, for signals of high intensity, the received level is sufficient to potentially cause discomfort or tissue damage to auditory or other systems. Overlaying these zones to a certain extent is the area within which masking ( i.e., when a sound interferes with or masks the ability of an animal to detect a signal of interest that is above the absolute hearing threshold) may occur; the masking zone may be highly variable in size.

Below, we provide additional detail regarding potential impacts on marine mammals and their habitat from noise in general, starting with hearing impairment, as well as from the specific activities Atlantic Shores plans to conduct, to the degree it is available (noting that there is limited information regarding the impacts of offshore wind construction on marine mammals).

Hearing Threshold Shift

Marine mammals exposed to high-intensity sound or to lower-intensity sound for prolonged periods can experience hearing threshold shift (TS), which NMFS defines as a change, usually an increase, in the threshold of audibility at a specified frequency or portion of an individual's hearing range above a previously established reference level expressed in decibels (NMFS, 2018). Threshold shifts can be permanent, in which case there is an irreversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range or temporary, in which there is reversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range and the animal's hearing threshold would fully recover over time (Southall et al., 2019a). Repeated sound exposure that leads to TTS could cause PTS.

When PTS occurs, there can be physical damage to the sound receptors in the ear ( i.e., tissue damage) whereas TTS represents primarily tissue fatigue and is reversible (Henderson et al., 2008). In addition, other investigators have suggested that TTS is within the normal bounds of physiological variability and tolerance and does not represent physical injury ( e.g., Ward, 1997; Southall et al., 2019a). Therefore, NMFS does not consider TTS to constitute auditory injury.

Relationships between TTS and PTS thresholds have not been studied in marine mammals, and there is no PTS data for cetaceans. However, such relationships are assumed to be similar to those in humans and other terrestrial mammals. Noise exposure can result in either a permanent shift in hearing thresholds from baseline (PTS; a 40 dB threshold shift approximates a PTS onset; e.g., Kryter et al., 1966; Miller, 1974; Henderson et al., 2008) or a temporary, recoverable shift in hearing that returns to baseline (a 6 dB threshold shift approximates a TTS onset; e.g., Southall et al., 2019a). Based on data from terrestrial mammals, a precautionary assumption is that the PTS thresholds, expressed in the unweighted peak sound pressure level metric (PK), for impulsive sounds (such as impact pile driving pulses) are at least 6 dB higher than the TTS thresholds and the weighted PTS cumulative sound exposure level thresholds are 15 (impulsive sounds) to 20 (non-impulsive sounds) dB higher than TTS cumulative sound exposure level thresholds (Southall et al., 2019a). Given the higher level of sound or longer exposure duration necessary to cause PTS as compared with TTS, PTS is less likely to occur as a result of these activities, but it is possible and a small amount has been proposed for authorization for several species.

TTS is the mildest form of hearing impairment that can occur during exposure to sound, with a TTS of 6 dB considered the minimum threshold shift clearly larger than any day-to-day or session-to-session variation in a subject's normal hearing ability (Schlundt et al., 2000; Finneran et al., 2000; Finneran et al., 2002). While experiencing TTS, the hearing threshold rises, and a sound must be at a higher level in order to be heard. In terrestrial and marine mammals, TTS can last from minutes or hours to days (in cases of strong TTS). In many cases, hearing sensitivity recovers rapidly after exposure to the sound ends. There is data on sound levels and durations necessary to elicit mild TTS for marine mammals, but recovery is complicated to predict and dependent on multiple factors.

Marine mammal hearing plays a critical role in communication with conspecifics, and interpretation of environmental cues for purposes such as predator avoidance and prey capture. Depending on the degree (elevation of threshold in dB), duration ( i.e., recovery time), and frequency range of TTS, and the context in which it is experienced, TTS can have effects on marine mammals ranging from discountable to serious depending on the degree of interference with marine mammals' hearing. For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that occurs during a time where ambient noise is lower and there are not as many competing sounds present. Alternatively, a larger amount and longer duration of TTS sustained during time when communication is critical ( e.g., for successful mother/calf interactions, consistent detection of prey) could have more serious impacts.

Currently, TTS data only exist for four species of cetaceans (bottlenose dolphin, beluga whale ( Delphinapterus leucas), harbor porpoise, and Yangtze finless porpoise ( Neophocaena asiaeorientalis)) and six species of pinnipeds (northern elephant seal ( Mirounga angustirostris), harbor seal, ring seal, spotted seal, bearded seal, and California sea lion ( Zalophus californianus)) that were exposed to a limited number of sound sources ( i.e., mostly tones and octave-band noise with limited numbers of exposure to impulsive sources such as seismic airguns or impact pile driving) in laboratory settings (Southall et al., 2019a). There is currently no data available on noise-induced hearing loss for mysticetes. For summaries of data on TTS or PTS in marine mammals or for further discussion of TTS or PTS onset thresholds, please see Southall et al. (2019a) and NMFS (2018).

Recent studies with captive odontocete species (bottlenose dolphin, harbor porpoise, beluga, and false killer whale) have observed increases in hearing threshold levels when individuals received a warning sound prior to exposure to a relatively loud sound (Nachtigall and Supin, 2013, 2015; Nachtigall et al., 2016a, 2016b, 2016c; Finneran, 2018; Nachtigall et al., 2018). These studies suggest that captive animals have a mechanism to reduce hearing sensitivity prior to impending loud sounds. Hearing change was observed to be frequency dependent and Finneran (2018) suggests hearing attenuation occurs within the cochlea or auditory nerve. Based on these observations on captive odontocetes, the authors suggest that wild animals may have a mechanism to self-mitigate the impacts of noise exposure by dampening their hearing during prolonged exposures of loud sound or if conditioned to anticipate intense sounds (Finneran, 2018; Nachtigall et al., 2018).

Behavioral Effects

Exposure of marine mammals to sound sources can result in, but is not limited to, no response or any of the following observable responses: increased alertness; orientation or attraction to a sound source; vocal modifications; cessation of feeding; cessation of social interaction; alteration of movement or diving behavior; habitat abandonment (temporary or permanent); and in severe cases, panic, flight, stampede, or stranding, potentially resulting in death (Southall et al., 2007). A review of marine mammal responses to anthropogenic sound was first conducted by Richardson (1995). More recent reviews address studies conducted since 1995 and focused on observations where the received sound level of the exposed marine mammal(s) was known or could be estimated (Nowacek et al., 2007; DeRuiter et al., 2012 and 2013; Ellison et al., 2012; Gomez et al., 2016). Gomez et al. (2016) conducted a review of the literature considering the contextual information of exposure in addition to received level and found that higher received levels were not always associated with more severe behavioral responses and vice versa. Southall et al. (2021) states that results demonstrate that some individuals of different species display clear yet varied responses, some of which have negative implications while others appear to tolerate high levels and that responses may not be fully predictable with simple acoustic exposure metrics ( e.g., received sound level). Rather, the authors state that differences among species and individuals along with contextual aspects of exposure ( e.g., behavioral state) appear to affect response probability.

Behavioral responses to sound are highly variable and context-specific. Many different variables can influence an animal's perception of and response to (nature and magnitude) an acoustic event. An animal's prior experience with a sound or sound source affects whether it is less likely (habituation) or more likely (sensitization) to respond to certain sounds in the future (animals can also be innately predisposed to respond to certain sounds in certain ways) (Southall et al., 2019a). Related to the sound itself, the perceived nearness of the sound, bearing of the sound (approaching vs. retreating), the similarity of a sound to biologically relevant sounds in the animal's environment ( i.e., calls of predators, prey, or conspecifics), and familiarity of the sound may affect the way an animal responds to the sound (Southall et al., 2007, DeRuiter et al., 2013). Individuals (of different age, gender, reproductive status, etc.) among most populations will have variable hearing capabilities, and differing behavioral sensitivities to sounds that will be affected by prior conditioning, experience, and current activities of those individuals. Often, specific acoustic features of the sound and contextual variables ( i.e., proximity, duration, or recurrence of the sound or the current behavior that the marine mammal is engaged in or its prior experience), as well as entirely separate factors, such as the physical presence of a nearby vessel, may be more relevant to the animal's response than the received level alone.

Overall, the variability of responses to acoustic stimuli depends on the species receiving the sound, the sound source, and the social, behavioral, or environmental contexts of exposure ( e.g., DeRuiter et al., 2012). For example, Goldbogen et al. (2013a) demonstrated that individual behavioral state was critically important in determining response of blue whales to sonar, noting that some individuals engaged in deep (greater than 50 m) feeding behavior had greater dive responses than those in shallow feeding or non-feeding conditions. Some blue whales in the Goldbogen et al. (2013a) study that were engaged in shallow feeding behavior demonstrated no clear changes in diving or movement even when received levels were high (~160 dB re 1µPa) for exposures to 3–4 kHz sonar signals, while deep feeding and non-feeding whales showed a clear response at exposures at lower received levels of sonar and pseudorandom noise. Southall et al. (2011) found that blue whales had a different response to sonar exposure depending on behavioral state, more pronounced when deep feeding/travel modes than when engaged in surface feeding.

With respect to distance influencing disturbance, DeRuiter et al. (2013) examined behavioral responses of Cuvier's beaked whales to mid-frequency sonar and found that whales responded strongly at low received levels (89–127 dB re 1µPa) by ceasing normal fluking and echolocation, swimming rapidly away, and extending both dive duration and subsequent non-foraging intervals when the sound source was 3.4–9.5 km away. Importantly, this study also showed that whales exposed to a similar range of received levels (78–106 dB re 1µPa) from distant sonar exercises (118 km away) did not elicit such responses, suggesting that context may moderate reactions. Thus, distance from the source is an important variable in influencing the type and degree of behavioral response and this variable is independent of the effect of received levels ( e.g., DeRuiter et al., 2013; Dunlop et al., 2017a, 2017b; Falcone et al., 2017; Dunlop et al., 2018; Southall et al., 2019a).

Ellison et al. (2012) outlined an approach to assessing the effects of sound on marine mammals that incorporates contextual-based factors. The authors recommend considering not just the received level of sound but also the activity the animal is engaged in at the time the sound is received, the nature and novelty of the sound ( i.e., is this a new sound from the animal's perspective), and the distance between the sound source and the animal. They submit that this “exposure context,” as described, greatly influences the type of behavioral response exhibited by the animal. Forney et al. (2017) also point out that an apparent lack of response ( e.g., no displacement or avoidance of a sound source) may not necessarily mean there is no cost to the individual or population, as some resources or habitats may be of such high value that animals may choose to stay, even when experiencing stress or hearing loss. Forney et al. (2017) recommend considering both the costs of remaining in an area of noise exposure such as TTS, PTS, or masking, which could lead to an increased risk of predation or other threats or a decreased capability to forage, and the costs of displacement, including potential increased risk of vessel strike, increased risks of predation or competition for resources, or decreased habitat suitable for foraging, resting, or socializing. This sort of contextual information is challenging to predict with accuracy for ongoing activities that occur over large spatial and temporal expanses. However, distance is one contextual factor for which data exist to quantitatively inform a take estimate, and the method for predicting Level B harassment in this rule does consider distance to the source. Other factors are often considered qualitatively in the analysis of the likely consequences of sound exposure where supporting information is available.

Behavioral change, such as disturbance manifesting in lost foraging time, in response to anthropogenic activities is often assumed to indicate a biologically significant effect on a population of concern. However, individuals may be able to compensate for some types and degrees of shifts in behavior, preserving their health and thus their vital rates and population dynamics. For example, New et al. (2013) developed a model simulating the complex social, spatial, behavioral and motivational interactions of coastal bottlenose dolphins in the Moray Firth, Scotland, to assess the biological significance of increased rate of behavioral disruptions caused by vessel traffic. Despite a modeled scenario in which vessel traffic increased from 70 to 470 vessels a year (a 6-fold increase in vessel traffic) in response to the construction of a proposed offshore renewables' facility, the dolphins' behavioral time budget, spatial distribution, motivations and social structure remained unchanged. Similarly, two bottlenose dolphin populations in Australia were also modeled over 5 years against a number of disturbances (Reed et al., 2020) and results indicate that habitat/noise disturbance had little overall impact on population abundances in either location, even in the most extreme impact scenarios modeled.

Friedlaender et al. (2016) provided the first integration of direct measures of prey distribution and density variables incorporated into across-individual analyses of behavior responses of blue whales to sonar and demonstrated a fivefold increase in the ability to quantify variability in blue whale diving behavior. These results illustrate that responses evaluated without such measurements for foraging animals may be misleading, which again illustrates the context-dependent nature of the probability of response.

The following subsections provide examples of behavioral responses that give an idea of the variability in behavioral responses that would be expected given the differential sensitivities of marine mammal species to sound, contextual factors, and the wide range of potential acoustic sources to which a marine mammal may be exposed. Behavioral responses that could occur for a given sound exposure should be determined from the literature that is available for each species, or extrapolated from closely related species when no information exists, along with contextual factors.

Avoidance and Displacement

Avoidance is the displacement of an individual from an area or migration path as a result of the presence of a sound or other stressors and is one of the most obvious manifestations of disturbance in marine mammals (Richardson et al., 1995). For example, gray whales ( Eschrichtius robustus) and humpback whales are known to change direction—deflecting from customary migratory paths—in order to avoid noise from airgun surveys (Malme et al., 1984; Dunlop et al., 2018). Avoidance is qualitatively different from the flight response but also differs in the magnitude of the response ( i.e., directed movement, rate of travel, etc.). Avoidance may be short-term with animals returning to the area once the noise has ceased ( e.g., Malme et al., 1984; Bowles et al., 1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007; Dähne et al., 2013; Russel et al., 2016). Longer-term displacement is possible, however, which may lead to changes in abundance or distribution patterns of the affected species in the affected region if habituation to the presence of the sound does not occur ( e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006; Forney et al., 2017). Avoidance of marine mammals during the construction of offshore wind facilities (specifically, impact pile driving) has been documented in the literature with some significant variation in the temporal and spatial degree of avoidance and with most studies focused on harbor porpoises as one of the most common marine mammals in European waters ( e.g., Tougaard et al., 2009; Dähne et al., 2013; Thompson et al., 2013; Russell et al., 2016; Brandt et al., 2018).

Available information on impacts to marine mammals from pile driving associated with offshore wind is limited to information on harbor porpoises and seals, as the vast majority of this research has occurred at European offshore wind projects where large whales and other odontocete species are uncommon. Harbor porpoises and harbor seals are considered to be behaviorally sensitive species ( e.g., Southall et al., 2007) and the effects of wind farm construction in Europe on these species has been well documented. These species have received particular attention in European waters due to their abundance in the North Sea (Hammond et al., 2002; Nachtsheim et al., 2021). A summary of the literature on documented effects of wind farm construction on harbor porpoise and harbor seals is described below.

Brandt et al. (2016) summarized the effects of the construction of eight offshore wind projects within the German North Sea ( i.e., Alpha Ventus, BARD Offshore I, Borkum West II, DanTysk, Global Tech I, Meerwind Süd/Ost, Nordsee Ost, and Riffgat) between 2009 and 2013 on harbor porpoises, combining PAM data from 2010–2013 and aerial surveys from 2009–2013 with data on noise levels associated with pile driving. Results of the analysis revealed significant declines in porpoise detections during pile driving when compared to 25–48 hours before pile driving began, with the magnitude of decline during pile driving clearly decreasing with increasing distances to the construction site. During the majority of projects, significant declines in detections (by at least 20 percent) were found within at least 5–10 km of the pile driving site, with declines at up to 20–30 km of the pile driving site documented in some cases. Similar results demonstrating the long-distance displacement of harbor porpoises (18—25 km) and harbor seals (up to 40 km) during impact pile driving have also been observed during the construction at multiple other European wind farms (Tougaard et al., 2009; Bailey et al., 2010; Dähne et al., 2013; Lucke et al., 2012; Haelters et al., 2015).

While harbor porpoises and seals tend to move several kilometers away from wind farm construction activities, the duration of displacement has been documented to be relatively temporary. In two studies at Horns Rev II using impact pile driving, harbor porpoise returned within 1–2 days following cessation of pile driving (Tougaard et al., 2009; Brandt et al., 2011). Similar recovery periods have been noted for harbor seals off England during the construction of four wind farms (Brasseur et al., 2012; Carroll et al., 2010; Hamre et al., 2011; Hastie et al., 2015; Russell et al., 2016). In some cases, an increase in harbor porpoise activity has been documented inside wind farm areas following construction ( e.g., Lindeboom et al., 2011). Other studies have noted longer term impacts after impact pile driving. Near Dogger Bank in Germany, harbor porpoises continued to avoid the area for over 2 years after construction began (Gilles et al., 2009). Approximately 10 years after construction of the Nysted wind farm, harbor porpoise abundance had not recovered to the original levels previously seen, although the echolocation activity was noted to have been increasing when compared to the previous monitoring period (Teilmann and Carstensen, 2012). However, overall, there are no indications for a population decline of harbor porpoises in European waters ( e.g., Brandt et al., 2016). Notably, where significant differences in displacement and return rates have been identified for these species, the occurrence of secondary project-specific influences such as use of mitigation measures ( e.g., bubble curtains, acoustic deterrent devices (ADDs)) or the manner in which species use the habitat in the Project Area are likely the driving factors of this variation.

NMFS notes the aforementioned studies from Europe involve installing much smaller piles than Atlantic Shores proposes to install and, therefore, we anticipate noise levels from impact pile driving to be louder. For this reason, we anticipate that greater distances of displacement than those observed in harbor porpoise and harbor seals in Europe are likely to occur off New Jersey. However, we do not anticipate any greater severity of response due to harbor porpoise and harbor seal habitat use off New Jersey or population-level consequences similar to European findings. In many cases, harbor porpoises and harbor seals are resident to the areas where European wind farms have been constructed. However, off New Jersey, harbor porpoises are primarily transient (with higher abundances in winter when foundation installation would not occur) and a very small percentage of the large harbor seal population are only seasonally present with no rookeries established. In summary, we anticipate that harbor porpoise and harbor seals will likely respond to pile driving by moving several kilometers away from the source but return to typical habitat use patterns when pile driving ceases.

Some avoidance behavior of other marine mammal species has been documented to be dependent on distance from the source. As described above, DeRuiter et al. (2013) noted that distance from a sound source may moderate marine mammal reactions in their study of Cuvier's beaked whales (an acoustically sensitive species), which showed the whales swimming rapidly and silently away when a sonar signal was 3.4–9.5 km away while showing no such reaction to the same signal when the signal was 118 km away even though the received levels were similar. Tyack et al. (1983) conducted playback studies of Surveillance Towed Array Sensor System (SURTASS) low frequency active (LFA) sonar in a gray whale migratory corridor off California. Similar to North Atlantic right whales, gray whales migrate close to shore (approximately +2 kms) and are low frequency hearing specialists. The LFA sonar source was placed within the gray whale migratory corridor (approximately 2 km offshore) and offshore of most, but not all, migrating whales (approximately 4 km offshore). These locations influenced received levels and distance to the source. For the inshore playbacks, not unexpectedly, the louder the source level of the playback ( i.e., the louder the received level), the more whales avoided the source at greater distances. Specifically, when the source level was 170 dB rms and 178 dB rms, whales avoided the inshore source at ranges of several hundred meters, similar to avoidance responses reported by Malme et al. (1983, 1984). Whales exposed to source levels of 185 dB rms demonstrated avoidance levels at ranges of +1 km. Where the offshore source broadcast at source levels of 185 and 200 dB, avoidance responses were greatly reduced. While there was observed deflection from course, in no case did a whale abandon its migratory behavior.

The signal context of the noise exposure has been shown to play an important role in avoidance responses. In a 2007–2008 Bahamas study, playback sounds of a potential predator—a killer whale—resulted in a similar but more pronounced reaction in beaked whales (an acoustically sensitive species), which included longer inter-dive intervals and a sustained straight-line departure of more than 20 km from the area (Boyd et al., 2008; Southall et al., 2009; Tyack et al., 2011). Atlantic Shores does not anticipate, and NMFS is not proposing to authorize take of beaked whales and, moreover, the sounds produced by Atlantic Shores do not have signal characteristics similar to predators. Therefore we would not expect such extreme reactions to occur. Southall et al. (2011) found that blue whales had a different response to sonar exposure depending on behavioral state, more pronounced when deep feeding/travel modes than when engaged in surface feeding.

One potential consequence of behavioral avoidance is the altered energetic expenditure of marine mammals because energy is required to move and avoid surface vessels or the sound field associated with active sonar (Frid and Dill, 2002). Most animals can avoid that energetic cost by swimming away at slow speeds or speeds that minimize the cost of transport (Miksis-Olds, 2006), as has been demonstrated in Florida manatees (Miksis-Olds, 2006). Those energetic costs increase, however, when animals shift from a resting state, which is designed to conserve an animal's energy, to an active state that consumes energy the animal would have conserved had it not been disturbed. Marine mammals that have been disturbed by anthropogenic noise and vessel approaches are commonly reported to shift from resting to active behavioral states, which would imply that they incur an energy cost.

Forney et al. (2017) detailed the potential effects of noise on marine mammal populations with high site fidelity, including displacement and auditory masking, noting that a lack of observed response does not imply absence of fitness costs and that apparent tolerance of disturbance may have population-level impacts that are less obvious and difficult to document. Avoidance of overlap between disturbing noise and areas and/or times of particular importance for sensitive species may be critical to avoiding population-level impacts because (particularly for animals with high site fidelity) there may be a strong motivation to remain in the area despite negative impacts. Forney et al. (2017) stated that, for these animals, remaining in a disturbed area may reflect a lack of alternatives rather than a lack of effects.

A flight response is a dramatic change in normal movement to a directed and rapid movement away from the perceived location of a sound source. The flight response differs from other avoidance responses in the intensity of the response ( e.g., directed movement, rate of travel). Relatively little information on flight responses of marine mammals to anthropogenic signals exist, although observations of flight responses to the presence of predators have occurred (Connor and Heithaus, 1996; Frid and Dill, 2002). The result of a flight response could range from brief, temporary exertion and displacement from the area where the signal provokes flight to, in extreme cases, beaked whale strandings (Cox et al., 2006; D'Amico et al., 2009). However, it should be noted that response to a perceived predator does not necessarily invoke flight (Ford and Reeves, 2008), and whether individuals are solitary or in groups may influence the response. Flight responses of marine mammals have been documented in response to mobile high intensity active sonar ( e.g., Tyack et al., 2011; DeRuiter et al., 2013; Wensveen et al., 2019), and more severe responses have been documented when sources are moving towards an animal or when they are surprised by unpredictable exposures (Watkins, 1986; Falcone et al., 2017). Generally speaking, however, marine mammals would be expected to be less likely to respond with a flight response to either stationary pile driving (which they can sense is stationary and predictable) or significantly lower-level HRG surveys, unless they are within the area ensonified above behavioral harassment thresholds at the moment the source is turned on (Watkins, 1986; Falcone et al., 2017).

Diving and Foraging

Changes in dive behavior in response to noise exposure can vary widely. They may consist of increased or decreased dive times and surface intervals as well as changes in the rates of ascent and descent during a dive ( e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013a; Goldbogen et al., 2013b). Variations in dive behavior may reflect interruptions in biologically significant activities ( e.g., foraging) or they may be of little biological significance. Variations in dive behavior may also expose an animal to potentially harmful conditions ( e.g., increasing the chance of ship-strike) or may serve as an avoidance response that enhances survivorship. The impact of a variation in diving resulting from an acoustic exposure depends on what the animal is doing at the time of the exposure, the type and magnitude of the response, and the context within which the response occurs ( e.g., the surrounding environmental and anthropogenic circumstances).

Nowacek et al. (2004) reported disruptions of dive behaviors in foraging North Atlantic right whales when exposed to an alerting stimulus, an action, they noted, that could lead to an increased likelihood of vessel strike. The alerting stimulus was in the form of an 18 minute exposure that included three 2-minute signals played three times sequentially. This stimulus was designed with the purpose of providing signals distinct to background noise that serve as localization cues. However, the whales did not respond to playbacks of either right whale social sounds or vessel noise, highlighting the importance of the sound characteristics in producing a behavioral reaction. Although source levels for the proposed pile driving activities may exceed the received level of the alerting stimulus described by Nowacek et al. (2004), proposed mitigation strategies (further described in the Proposed Mitigation section) will reduce the severity of response to proposed pile driving activities. Converse to the behavior of North Atlantic right whales, Indo-Pacific humpback dolphins have been observed to dive for longer periods of time in areas where vessels were present and/or approaching (Ng and Leung, 2003). In both of these studies, the influence of the sound exposure cannot be decoupled from the physical presence of a surface vessel, thus complicating interpretations of the relative contribution of each stimulus to the response. Indeed, the presence of surface vessels, their approach, and speed of approach, seemed to be significant factors in the response of the Indo-Pacific humpback dolphins (Ng and Leung, 2003). Low frequency signals of the Acoustic Thermometry of Ocean Climate (ATOC) sound source were not found to affect dive times of humpback whales in Hawaiian waters (Frankel and Clark, 2000) or to overtly affect elephant seal dives (Costa et al., 2003). They did, however, produce subtle effects that varied in direction and degree among the individual seals, illustrating the equivocal nature of behavioral effects and consequent difficulty in defining and predicting them.

Disruption of feeding behavior can be difficult to correlate with anthropogenic sound exposure, so it is usually inferred by observed displacement from known foraging areas, the cessation of secondary indicators of foraging ( e.g., bubble nets or sediment plumes), or changes in dive behavior. As for other types of behavioral response, the frequency, duration, and temporal pattern of signal presentation, as well as differences in species sensitivity, are likely contributing factors to differences in response in any given circumstance ( e.g., Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006a; Yazvenko et al., 2007; Southall et al., 2019b). An understanding of the energetic requirements of the affected individuals and the relationship between prey availability, foraging effort and success, and the life history stage of the animal can facilitate the assessment of whether foraging disruptions are likely to incur fitness consequences (Goldbogen et al., 2013b; Farmer et al., 2018; Pirotta et al., 2018; Southall et al., 2019a; Pirotta et al., 2021).

Impacts on marine mammal foraging rates from noise exposure have been documented, though there is little data regarding the impacts of offshore turbine construction specifically. Several broader examples follow, and it is reasonable to expect that exposure to noise produced during the 5 years the proposed rule would be effective could have similar impacts.

Visual tracking, passive acoustic monitoring, and movement recording tags were used to quantify sperm whale behavior prior to, during, and following exposure to airgun arrays at received levels in the range 140–160 dB at distances of 7–13 km, following a phase-in of sound intensity and full array exposures at 1–13 km (Madsen et al., 2006a; Miller et al., 2009). Sperm whales did not exhibit horizontal avoidance behavior at the surface. However, foraging behavior may have been affected. The sperm whales exhibited 19 percent less vocal (buzz) rate during full exposure relative to post exposure, and the whale that was approached most closely had an extended resting period and did not resume foraging until the airguns had ceased firing. The remaining whales continued to execute foraging dives throughout exposure; however, swimming movements during foraging dives were 6 percent lower during exposure than control periods (Miller et al., 2009). Miller et al. (2009) noted that more data are required to understand whether the differences were due to exposure or natural variation in sperm whale behavior.

Balaenopterid whales exposed to moderate low-frequency signals similar to the ATOC sound source demonstrated no variation in foraging activity (Croll et al., 2001), whereas five out of six North Atlantic right whales exposed to an acoustic alarm interrupted their foraging dives (Nowacek et al., 2004). Although the received sound pressure levels (SPLs) were similar in the latter two studies, the frequency, duration, and temporal pattern of signal presentation were different. These factors, as well as differences in species sensitivity, are likely contributing factors to the differential response. The source levels of both the proposed construction and HRG activities exceed the source levels of the signals described by Nowacek et al. (2004) and Croll et al. (2001), and noise generated by Atlantic Shores' activities at least partially overlap in frequency with the described signals. Blue whales exposed to mid-frequency sonar in the Southern California Bight were less likely to produce low frequency calls usually associated with feeding behavior (Melcón et al., 2012). However, Melcón et al. (2012) were unable to determine if suppression of low frequency calls reflected a change in their feeding performance or abandonment of foraging behavior and indicated that implications of the documented responses are unknown. Further, it is not known whether the lower rates of calling actually indicated a reduction in feeding behavior or social contact since the study used data from remotely deployed, passive acoustic monitoring buoys. Results from the 2010–2011 field season of a behavioral response study in Southern California waters indicated that, in some cases and at low received levels, tagged blue whales responded to mid-frequency sonar but that those responses were mild and there was a quick return to their baseline activity (Southall et al., 2011; Southall et al., 2012b, Southall et al., 2019).

Information on or estimates of the energetic requirements of the individuals and the relationship between prey availability, foraging effort and success, and the life history stage of the animal will help better inform a determination of whether foraging disruptions incur fitness consequences. Foraging strategies may impact foraging efficiency, such as by reducing foraging effort and increasing success in prey detection and capture, in turn promoting fitness and allowing individuals to better compensate for foraging disruptions. Surface feeding blue whales did not show a change in behavior in response to mid-frequency simulated and real sonar sources with received levels between 90 and 179 dB re 1 µPa, but deep feeding and non-feeding whales showed temporary reactions including cessation of feeding, reduced initiation of deep foraging dives, generalized avoidance responses, and changes to dive behavior (DeRuiter et al., 2017; Goldbogen et al., 2013b; Sivle et al., 2015). Goldbogen et al. (2013b) indicate that disruption of feeding and displacement could impact individual fitness and health. However, for this to be true, we would have to assume that an individual whale could not compensate for this lost feeding opportunity by either immediately feeding at another location, by feeding shortly after cessation of acoustic exposure, or by feeding at a later time. There is no indication that individual fitness and health would be impacted, particularly since unconsumed prey would likely still be available in the environment in most cases following the cessation of acoustic exposure.

Similarly, while the rates of foraging lunges decrease in humpback whales due to sonar exposure, there was variability in the response across individuals, with one animal ceasing to forage completely and another animal starting to forage during the exposure (Sivle et al., 2016). In addition, almost half of the animals that demonstrated avoidance were foraging before the exposure but the others were not; the animals that avoided while not feeding responded at a slightly lower received level and greater distance than those that were feeding (Wensveen et al., 2017). These findings indicate the behavioral state of the animal and foraging strategies play a role in the type and severity of a behavioral response. For example, when the prey field was mapped and used as a covariate in examining how behavioral state of blue whales is influenced by mid-frequency sound, the response in blue whale deep-feeding behavior was even more apparent, reinforcing the need for contextual variables to be included when assessing behavioral responses (Friedlaender et al., 2016).

Vocalizations and Auditory Masking

Marine mammals vocalize for different purposes and across multiple modes, such as whistling, production of echolocation clicks, calling, and singing. Changes in vocalization behavior in response to anthropogenic noise can occur for any of these modes and may result directly from increased vigilance or a startle response, or from a need to compete with an increase in background noise (see Erbe et al., 2016 review on communication masking), the latter of which is described more below.

For example, in the presence of potentially masking signals, humpback whales and killer whales have been observed to increase the length of their songs (Miller et al., 2000; Fristrup et al., 2003; Foote et al., 2004) and blue whales increased song production (Di Iorio and Clark, 2009), while North Atlantic right whales have been observed to shift the frequency content of their calls upward while reducing the rate of calling in areas of increased anthropogenic noise (Parks et al., 2007). In some cases, animals may cease or reduce sound production during production of aversive signals (Bowles et al., 1994; Thode et al., 2020; Cerchio et al., 2014; McDonald et al., 1995). Blackwell et al. (2015) showed that whales increased calling rates as soon as airgun signals were detectable before ultimately decreasing calling rates at higher received levels.

Sound can disrupt behavior through masking, or interfering with, an animal's ability to detect, recognize, or discriminate between acoustic signals of interest ( e.g., those used for intraspecific communication and social interactions, prey detection, predator avoidance, or navigation) (Richardson et al., 1995; Erbe and Farmer, 2000; Tyack, 2000; Erbe et al., 2016). Masking occurs when the receipt of a sound is interfered with by another coincident sound at similar frequencies and at similar or higher intensity, and may occur whether the sound is natural ( e.g., snapping shrimp, wind, waves, precipitation) or anthropogenic ( e.g., shipping, sonar, seismic exploration) in origin. The ability of a noise source to mask biologically important sounds depends on the characteristics of both the noise source and the signal of interest ( e.g., signal-to-noise ratio, temporal variability, direction), in relation to each other and to an animal's hearing abilities ( e.g., sensitivity, frequency range, critical ratios, frequency discrimination, directional discrimination, age, or TTS hearing loss), and existing ambient noise and propagation conditions.

Masking these acoustic signals can disturb the behavior of individual animals, groups of animals, or entire populations. Masking can lead to behavioral changes including vocal changes ( e.g., Lombard effect, increasing amplitude, or changing frequency), cessation of foraging or lost foraging opportunities, and leaving an area, to both signalers and receivers, in an attempt to compensate for noise levels (Erbe et al., 2016) or because sounds that would typically have triggered a behavior were not detected. In humans, significant masking of tonal signals occurs as a result of exposure to noise in a narrow band of similar frequencies. As the sound level increases, though, the detection of frequencies above those of the masking stimulus decreases also. This principle is expected to apply to marine mammals as well because of common biomechanical cochlear properties across taxa.

Therefore, when the coincident (masking) sound is man-made, it may be considered harassment when disrupting behavioral patterns. It is important to distinguish TTS and PTS, which persist after the sound exposure, from masking, which only occurs during the sound exposure. Because masking (without resulting in threshold shift) is not associated with abnormal physiological function, it is not considered a physiological effect, but rather a potential behavioral effect.

The frequency range of the potentially masking sound is important in determining any potential behavioral impacts. For example, low-frequency signals may have less effect on high-frequency echolocation sounds produced by odontocetes but are more likely to affect detection of mysticete communication calls and other potentially important natural sounds such as those produced by surf and some prey species. The masking of communication signals by anthropogenic noise may be considered as a reduction in the communication space of animals ( e.g., Clark et al., 2009; Matthews et al., 2017) and may result in energetic or other costs as animals change their vocalization behavior ( e.g., Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt et al., 2009). Masking can be reduced in situations where the signal and noise come from different directions (Richardson et al., 1995), through amplitude modulation of the signal, or through other compensatory behaviors (Houser and Moore, 2014). Masking can be tested directly in captive species ( e.g., Erbe, 2008), but in wild populations it must be either modeled or inferred from evidence of masking compensation. There are few studies addressing real-world masking sounds likely to be experienced by marine mammals in the wild ( e.g., Branstetter et al., 2013; Cholewiak et al., 2018).

The echolocation calls of toothed whales are subject to masking by high-frequency sound. Human data indicate low-frequency sound can mask high-frequency sounds ( i.e., upward masking). Studies on captive odontocetes by Au et al. (1974, 1985, 1993) indicate that some species may use various processes to reduce masking effects ( e.g., adjustments in echolocation call intensity or frequency as a function of background noise conditions). There is also evidence that the directional hearing abilities of odontocetes are useful in reducing masking at the high-frequencies these cetaceans use to echolocate, but not at the low-to-moderate frequencies they use to communicate (Zaitseva et al., 1980). A study by Nachtigall and Supin (2008) showed that false killer whales adjust their hearing to compensate for ambient sounds and the intensity of returning echolocation signals.

Impacts on signal detection, measured by masked detection thresholds, are not the only important factors to address when considering the potential effects of masking. As marine mammals use sound to recognize conspecifics, prey, predators, or other biologically significant sources (Branstetter et al., 2016), it is also important to understand the impacts of masked recognition thresholds (often called “informational masking”). Branstetter et al. (2016) measured masked recognition thresholds for whistle-like sounds of bottlenose dolphins and observed that they are approximately 4 dB above detection thresholds (energetic masking) for the same signals. Reduced ability to recognize a conspecific call or the acoustic signature of a predator could have severe negative impacts. Branstetter et al. (2016) observed that if “quality communication” is set at 90 percent recognition the output of communication space models (which are based on 50 percent detection) would likely result in a significant decrease in communication range.

As marine mammals use sound to recognize predators (Allen et al., 2014; Cummings and Thompson, 1971; Curé et al., 2015; Fish and Vania, 1971), the presence of masking noise may also prevent marine mammals from responding to acoustic cues produced by their predators, particularly if it occurs in the same frequency band. For example, harbor seals that reside in the coastal waters off British Columbia are frequently targeted by mammal-eating killer whales. The seals acoustically discriminate between the calls of mammal-eating and fish-eating killer whales (Deecke et al., 2002), a capability that should increase survivorship while reducing the energy required to attend to all killer whale calls. Similarly, sperm whales (Curé et al., 2016; Isojunno et al., 2016), long-finned pilot whales (Visser et al., 2016), and humpback whales (Curé et al., 2015) changed their behavior in response to killer whale vocalization playbacks; these findings indicate that some recognition of predator cues could be missed if the killer whale vocalizations were masked. The potential effects of masked predator acoustic cues depends on the duration of the masking noise and the likelihood of a marine mammal encountering a predator during the time that detection and recognition of predator cues are impeded.

Redundancy and context can also facilitate detection of weak signals. These phenomena may help marine mammals detect weak sounds in the presence of natural or manmade noise. Most masking studies in marine mammals present the test signal and the masking noise from the same direction. The dominant background noise may be highly directional if it comes from a particular anthropogenic source such as a ship or industrial site. Directional hearing may significantly reduce the masking effects of these sounds by improving the effective signal-to-noise ratio.

Masking affects both senders and receivers of acoustic signals and, at higher levels and longer duration, can potentially have long-term chronic effects on marine mammals at the population level as well as at the individual level. Low-frequency ambient sound levels have increased by as much as 20 dB (more than three times in terms of SPL) in the world's ocean from pre-industrial periods, with most of the increase from distant commercial shipping (Hildebrand, 2009; Cholewiak et al., 2018). All anthropogenic sound sources, but especially chronic and lower-frequency signals ( e.g., from commercial vessel traffic), contribute to elevated ambient sound levels, thus intensifying masking.

In addition to making it more difficult for animals to perceive and recognize acoustic cues in their environment, anthropogenic sound presents separate challenges for animals that are vocalizing. When they vocalize, animals are aware of environmental conditions that affect the “active space” (or communication space) of their vocalizations, which is the maximum area within which their vocalizations can be detected before it drops to the level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr et al., 2003). Animals are also aware of environmental conditions that affect whether listeners can discriminate and recognize their vocalizations from other sounds, which is more important than simply detecting that a vocalization is occurring (Brenowitz, 1982; Brumm et al., 2004; Dooling, 2004; Marten and Marler, 1977; Patricelli and Blickley, 2006). Most species that vocalize have evolved with an ability to make adjustments to their vocalizations to increase the signal-to-noise ratio, active space, and recognizability/distinguishability of their vocalizations in the face of temporary changes in background noise (Brumm et al., 2004; Patricelli and Blickley, 2006). Vocalizing animals can make adjustments to vocalization characteristics such as the frequency structure, amplitude, temporal structure, and temporal delivery (repetition rate), or ceasing to vocalize.

Many animals will combine several of these strategies to compensate for high levels of background noise. Anthropogenic sounds that reduce the signal-to-noise ratio of animal vocalizations, increase the masked auditory thresholds of animals listening for such vocalizations, or reduce the active space of an animal's vocalizations impair communication between animals. Most animals that vocalize have evolved strategies to compensate for the effects of short-term or temporary increases in background or ambient noise on their songs or calls. Although the fitness consequences of these vocal adjustments are not directly known in all instances, like most other trade-offs animals must make, some of these strategies likely come at a cost (Patricelli and Blickley, 2006; Noren et al., 2017; Noren et al., 2020). Shifting songs and calls to higher frequencies may also impose energetic costs (Lambrechts, 1996).

Marine mammals are also known to make vocal changes in response to anthropogenic noise. In cetaceans, vocalization changes have been reported from exposure to anthropogenic noise sources such as sonar, vessel noise, and seismic surveying (see the following for examples: Gordon et al., 2003; Di Iorio and Clark, 2009; Hatch et al., 2012; Holt et al., 2009; Holt et al., 2011; Lesage et al., 1999; McDonald et al., 2009; Parks et al., 2007; Risch et al., 2012; Rolland et al., 2012; Sorenson et al., 2023), as well as changes in the natural acoustic environment (Dunlop et al., 2014). Vocal changes can be temporary, or can be persistent. For example, model simulation suggests that the increase in starting frequency for the North Atlantic right whale upcall over the last 50 years resulted in increased detection ranges between right whales. The frequency shift, coupled with an increase in call intensity by 20 dB, led to a call detectability range of less than 3 km to over 9 km (Tennessen and Parks, 2016). Holt et al. (2009) measured killer whale call source levels and background noise levels in the 1 to 40 kHz band and reported that the whales increased their call source levels by 1 dB SPL for every 1 dB SPL increase in background noise level. Similarly, another study on St. Lawrence River belugas reported a similar rate of increase in vocalization activity in response to passing vessels (Scheifele et al., 2005). Di Iorio and Clark (2009) showed that blue whale calling rates vary in association with seismic sparker survey activity, with whales calling more on days with surveys than on days without surveys. They suggested that the whales called more during seismic survey periods as a way to compensate for the elevated noise conditions.

In some cases, these vocal changes may have fitness consequences, such as an increase in metabolic rates and oxygen consumption, as observed in bottlenose dolphins when increasing their call amplitude (Holt et al., 2015). A switch from vocal communication to physical, surface-generated sounds such as pectoral fin slapping or breaching was observed for humpback whales in the presence of increasing natural background noise levels, indicating that adaptations to masking may also move beyond vocal modifications (Dunlop et al., 2010).

While these changes all represent possible tactics by the sound-producing animal to reduce the impact of masking, the receiving animal can also reduce masking by using active listening strategies such as orienting to the sound source, moving to a quieter location, or reducing self-noise from hydrodynamic flow by remaining still. The temporal structure of noise ( e.g., amplitude modulation) may also provide a considerable release from masking through comodulation masking release (a reduction of masking that occurs when broadband noise, with a frequency spectrum wider than an animal's auditory filter bandwidth at the frequency of interest, is amplitude modulated) (Branstetter and Finneran, 2008; Branstetter et al., 2013). Signal type ( e.g., whistles, burst-pulse, sonar clicks) and spectral characteristics ( e.g., frequency modulated with harmonics) may further influence masked detection thresholds (Branstetter et al., 2016; Cunningham et al., 2014).

Masking is more likely to occur in the presence of broadband, relatively continuous noise sources, such as vessels. Several studies have shown decreases in marine mammal communication space and changes in behavior as a result of the presence of vessel noise. For example, right whales were observed to shift the frequency content of their calls upward while reducing the rate of calling in areas of increased anthropogenic noise (Parks et al., 2007) as well as increasing the amplitude (intensity) of their calls (Parks, 2009; Parks et al., 2011). Clark et al. (2009) observed that right whales' communication space decreased by up to 84 percent in the presence of vessels. Cholewiak et al. (2018) also observed loss in communication space in Stellwagen National Marine Sanctuary for North Atlantic right whales, fin whales, and humpback whales with increased ambient noise and shipping noise. Although humpback whales off Australia did not change the frequency or duration of their vocalizations in the presence of ship noise, their source levels were lower than expected based on source level changes to wind noise, potentially indicating some signal masking (Dunlop, 2016). Multiple delphinid species have also been shown to increase the minimum or maximum frequencies of their whistles in the presence of anthropogenic noise and reduced communication space (for examples see: Holt et al., 2009; Holt et al., 2011; Gervaise et al., 2012; Williams et al., 2013; Hermannsen et al., 2014; Papale et al., 2015; Liu et al., 2017). While masking impacts are not a concern from lower intensity, higher frequency HRG surveys, some degree of masking would be expected in the vicinity of turbine pile driving and concentrated support vessel operation. However, pile driving is an intermittent sound and would not be continuous throughout a day.

Habituation and Sensitization

Habituation can occur when an animal's response to a stimulus wanes with repeated exposure, usually in the absence of unpleasant associated events (Wartzok et al., 2003). Animals are most likely to habituate to sounds that are predictable and unvarying. It is important to note that habituation is appropriately considered as a “progressive reduction in response to stimuli that are perceived as neither aversive nor beneficial,” rather than as, more generally, moderation in response to human disturbance having a neutral or positive outcome (Bejder et al., 2009). The opposite process is sensitization, when an unpleasant experience leads to subsequent responses, often in the form of avoidance, at a lower level of exposure.

Both habituation and sensitization require an ongoing learning process. As noted, behavioral state may affect the type of response. For example, animals that are resting may show greater behavioral change in response to disturbing sound levels than animals that are highly motivated to remain in an area for feeding (Richardson et al., 1995; National Research Council (NRC), 2003; Wartzok et al., 2003; Southall et al., 2019b). Controlled experiments with captive marine mammals have shown pronounced behavioral reactions, including avoidance of loud sound sources ( e.g., Ridgway et al., 1997; Finneran et al., 2003; Houser et al., 2013a; Houser et al., 2013b; Kastelein et al., 2018). Observed responses of wild marine mammals to loud impulsive sound sources (typically airguns or acoustic harassment devices) have been varied but often consist of avoidance behavior or other behavioral changes suggesting discomfort (Morton and Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007; Tougaard et al., 2009; Brandt et al., 2011; Brandt et al., 2012; Dähne et al., 2013; Brandt et al., 2014; Russell et al., 2016; Brandt et al., 2018).

Stone (2015) reported data from at-sea observations during 1,196 airgun surveys from 1994 to 2010. When large arrays of airguns (considered to be 500 in 3 or more) were firing, lateral displacement, more localized avoidance, or other changes in behavior were evident for most odontocetes. However, significant responses to large arrays were found only for the minke whale and fin whale. Behavioral responses observed included changes in swimming or surfacing behavior with indications that cetaceans remained near the water surface at these times. Behavioral observations of gray whales during an airgun survey monitored whale movements and respirationspre-, during-, and post-seismic survey (Gailey et al., 2016). Behavioral state and water depth were the best 'natural' predictors of whale movements and respiration and after considering natural variation, none of the response variables were significantly associated with survey or vessel sounds. Many delphinids approach low-frequency airgun source vessels with no apparent discomfort or obvious behavioral change ( e.g., Barkaszi et al., 2012), indicating the importance of frequency output in relation to the species' hearing sensitivity.

Physiological Responses

An animal's perception of a threat may be sufficient to trigger stress responses consisting of some combination of behavioral responses, autonomic nervous system responses, neuroendocrine responses, or immune responses ( e.g., Seyle, 1950; Moberg, 2000). In many cases, an animal's first and sometimes most economical (in terms of energetic costs) response is behavioral avoidance of the potential stressor. Autonomic nervous system responses to stress typically involve changes in heart rate, blood pressure, and gastrointestinal activity. These responses have a relatively short duration and may or may not have a significant long-term effect on an animal's fitness.

Neuroendocrine stress responses often involve the hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine functions that are affected by stress—including immune competence, reproduction, metabolism, and behavior—are regulated by pituitary hormones. Stress-induced changes in the secretion of pituitary hormones have been implicated in failed reproduction, altered metabolism, reduced immune competence, and behavioral disturbance ( e.g., Moberg, 1987; Blecha, 2000). Increases in the circulation of glucocorticoids are also equated with stress (Romano et al., 2004).

The primary distinction between stress (which is adaptive and does not normally place an animal at risk) and “distress” is the cost of the response. During a stress response, an animal uses glycogen stores that can be quickly replenished once the stress is alleviated. In such circumstances, the cost of the stress response would not pose serious fitness consequences. However, when an animal does not have sufficient energy reserves to satisfy the energetic costs of a stress response, energy resources must be diverted from other functions. This state of distress will last until the animal replenishes its energetic reserves sufficiently to restore normal function.

Relationships between these physiological mechanisms, animal behavior, and the costs of stress responses are well studied through controlled experiments and for both laboratory and free-ranging animals ( e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; Lankford et al., 2005). Stress responses due to exposure to anthropogenic sounds or other stressors and their effects on marine mammals have also been reviewed (Fair and Becker, 2000; Romano et al., 2002b) and, more rarely, studied in wild populations ( e.g., Lusseau and Bejder, 2007; Romano et al., 2002a; Rolland et al., 2012). For example, Rolland et al. (2012) found that noise reduction from reduced ship traffic in the Bay of Fundy was associated with decreased stress in North Atlantic right whales.

These and other studies lead to a reasonable expectation that some marine mammals will experience physiological stress responses upon exposure to acoustic stressors and that it is possible that some of these would be classified as “distress.” In addition, any animal experiencing TTS would likely also experience stress responses (NRC, 2003, 2017).

Respiration naturally varies with different behaviors and variations in respiration rate as a function of acoustic exposure can be expected to co-occur with other behavioral reactions, such as a flight response or an alteration in diving. However, respiration rates in and of themselves may be representative of annoyance or an acute stress response. Mean exhalation rates of gray whales at rest and while diving were found to be unaffected by seismic surveys conducted adjacent to the whale feeding grounds (Gailey et al., 2007). Studies with captive harbor porpoises show increased respiration rates upon introduction of acoustic alarms (Kastelein et al., 2001; Kastelein et al., 2006a) and emissions for underwater data transmission (Kastelein et al., 2005). However, exposure of the same acoustic alarm to a striped dolphin under the same conditions did not elicit a response (Kastelein et al., 2006a), again highlighting the importance in understanding species differences in the tolerance of underwater noise when determining the potential for impacts resulting from anthropogenic sound exposure.

Stranding

The definition for a stranding under title IV of the MMPA is that (A) a marine mammal is dead and is (i) on a beach or shore of the United States; or (ii) in waters under the jurisdiction of the United States (including any navigable waters); or (B) a marine mammal is alive and is (i) on a beach or shore of the United States and is unable to return to the water; (ii) on a beach or shore of the United States and, although able to return to the water, is in need of apparent medical attention; or (iii) in the waters under the jurisdiction of the United States (including any navigable waters), but is unable to return to its natural habitat under its own power or without assistance (16 U.S.C. 1421h).

Marine mammal strandings have been linked to a variety of causes, such as illness from exposure to infectious agents, biotoxins, or parasites; starvation; unusual oceanographic or weather events; or anthropogenic causes including fishery interaction, vessel strike, entrainment, entrapment, sound exposure, or combinations of these stressors sustained concurrently or in series. There have been multiple events worldwide in which marine mammals (primarily beaked whales, or other deep divers) have stranded coincident with relatively nearby activities utilizing loud sound sources (primarily military training events), and five in which mid-frequency active sonar has been more definitively determined to have been a contributing factor.

There are multiple theories regarding the specific mechanisms responsible for marine mammal strandings caused by exposure to loud sounds. One primary theme is the behaviorally mediated responses of deep-diving species (odontocetes), in which their startled response to an acoustic disturbance (1) affects ascent or descent rates, the time they stay at depth or the surface, or other regular dive patterns that are used to physiologically manage gas formation and absorption within their bodies, such that the formation or growth of gas bubbles damages tissues or causes other injury, or (2) results in their flight to shallow areas, enclosed bays, or other areas considered “out of habitat,” in which they become disoriented and physiologically compromised. For more information on marine mammal stranding events and potential causes, please see the Mortality and Stranding section of NMFS Proposed Incidental Take Regulations for the Navy's Training and Testing Activities in the Hawaii-Southern California Training and Testing Study Area (50 CFR part 218, Volume 83, No. 123, June 26, 2018).

The construction activities proposed by Atlantic Shores ( i.e., pile driving) do not inherently have the potential to result in marine mammal strandings. While vessel strikes could kill or injure a marine mammals (which may eventually strand), the required mitigation measures would reduce the potential for take from these activities to de minimis levels (see Proposed Mitigation section for more details). As described above, no mortality or serious injury is anticipated or proposed to be authorized from any project activities.

Of the strandings documented to date worldwide, NMFS is not aware of any being attributed to pile driving or the types of HRG equipment proposed for use during the project. Recently, there has been heightened interest in HRG surveys and their potential role in recent marine mammals strandings along the U.S. east coast. HRG surveys involve the use of certain sources to image the ocean bottom, which are very different from seismic airguns used in oil and gas surveys or tactical military sonar, in that they produce much smaller impact zones. Marine mammals may respond to exposure to these sources by, for example, avoiding the immediate area, which is why offshore wind developers have authorization to allow for Level B (behavioral) harassment, including Atlantic Shores. However, because of the combination of lower source levels, higher frequency, narrower beam-width (for some sources), and other factors, the area within which a marine mammal might be expected to be behaviorally disturbed by HRG sources is much smaller (by orders of magnitude) than the impact areas for seismic airguns or the military sonar with which a small number of marine mammal have been causally associated. Specifically, estimated harassment zones for HRG surveys are typically less than 200 m (656.2 ft; such as those associated with the project), while zones for military mid-frequency active sonar or seismic airgun surveys typically extend for several kms ranging up to 10s of km. Further, because of this much smaller ensonified area, any marine mammal exposure to HRG sources is reasonably expected to be at significantly lower levels and shorter duration (associated with less severe responses), and there is no evidence suggesting, or reason to speculate, that marine mammals exposed to HRG survey noise are likely to be injured, much less strand, as a result. Last, all but one of the small number of marine mammal stranding events that have been causally associated with exposure to loud sound sources have been deep-diving toothed whale species (not mysticetes), which are known to respond differently to loud sounds.

Potential Effects of Disturbance on Marine Mammal Fitness

The different ways that marine mammals respond to sound are sometimes indicators of the ultimate effect that exposure to a given stimulus will have on the well-being (survival, reproduction, etc.) of an animal. There is numerous data relating the exposure of terrestrial mammals from sound to effects on reproduction or survival, and data for marine mammals continues to grow. Several authors have reported that disturbance stimuli may cause animals to abandon nesting and foraging sites (Sutherland and Crockford, 1993); may cause animals to increase their activity levels and suffer premature deaths or reduced reproductive success when their energy expenditures exceed their energy budgets (Daan et al., 1996; Feare, 1976; Mullner et al., 2004); or may cause animals to experience higher predation rates when they adopt risk-prone foraging or migratory strategies (Frid and Dill, 2002). Each of these studies addressed the consequences of animals shifting from one behavioral state ( e.g., resting or foraging) to another behavioral state ( e.g., avoidance or escape behavior) because of human disturbance or disturbance stimuli.

Attention is the cognitive process of selectively concentrating on one aspect of an animal's environment while ignoring other things (Posner, 1994). Because animals (including humans) have limited cognitive resources, there is a limit to how much sensory information they can process at any time. The phenomenon called “attentional capture” occurs when a stimulus (usually a stimulus that an animal is not concentrating on or attending to) “captures” an animal's attention. This shift in attention can occur consciously or subconsciously (for example, when an animal hears sounds that it associates with the approach of a predator) and the shift in attention can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has captured an animal's attention, the animal can respond by ignoring the stimulus, assuming a “watch and wait” posture, or treat the stimulus as a disturbance and respond accordingly, which includes scanning for the source of the stimulus or “vigilance” (Cowlishaw et al., 2004).

Vigilance is an adaptive behavior that helps animals determine the presence or absence of predators, assess their distance from conspecifics, or to attend cues from prey (Bednekoff and Lima, 1998; Treves, 2000). Despite those benefits, however, vigilance has a cost of time; when animals focus their attention on specific environmental cues, they are not attending to other activities such as foraging or resting. These effects have generally not been demonstrated for marine mammals, but studies involving fish and terrestrial animals have shown that increased vigilance may substantially reduce feeding rates (Saino, 1994; Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). Animals will spend more time being vigilant, which may translate to less time foraging or resting, when disturbance stimuli approach them more directly, remain at closer distances, have a greater group size ( e.g., multiple surface vessels), or when they co-occur with times that an animal perceives increased risk ( e.g., when they are giving birth or accompanied by a calf).

The primary mechanism by which increased vigilance and disturbance appear to affect the fitness of individual animals is by disrupting an animal's time budget and, as a result, reducing the time they might spend foraging and resting (which increases an animal's activity rate and energy demand while decreasing their caloric intake/energy). In a study of northern resident killer whales off Vancouver Island, exposure to boat traffic was shown to reduce foraging opportunities and increase traveling time (Holt et al., 2021). A simple bioenergetics model was applied to show that the reduced foraging opportunities equated to a decreased energy intake of 18 percent while the increased traveling incurred an increased energy output of 3–4 percent, which suggests that a management action based on avoiding interference with foraging might be particularly effective.

On a related note, many animals perform vital functions, such as feeding, resting, traveling, and socializing, on a diel cycle (24-hour cycle). Behavioral reactions to noise exposure (such as disruption of critical life functions, displacement, or avoidance of important habitat) are more likely to be significant for fitness if they last more than one diel cycle or recur on subsequent days (Southall et al., 2007). Consequently, a behavioral response lasting less than 1 day and not recurring on subsequent days is not considered particularly severe unless it could directly affect reproduction or survival (Southall et al., 2007). It is important to note the difference between behavioral reactions lasting or recurring over multiple days and anthropogenic activities lasting or recurring over multiple days. For example, just because certain activities last for multiple days does not necessarily mean that individual animals will be either exposed to those activity-related stressors ( i.e., sonar) for multiple days or further exposed in a manner that would result in sustained multi-day substantive behavioral responses. However, special attention is warranted where longer-duration activities overlay areas in which animals are known to congregate for longer durations for biologically important behaviors.

There are few studies that directly illustrate the impacts of disturbance on marine mammal populations. Lusseau and Bejder (2007) present data from three long-term studies illustrating the connections between disturbance from whale-watching boats and population-level effects in cetaceans. In Shark Bay, Australia, the abundance of bottlenose dolphins was compared within adjacent control and tourism sites over three consecutive 4.5-year periods of increasing tourism levels. Between the second and third time periods, in which tourism doubled, dolphin abundance decreased by 15 percent in the tourism area and did not change significantly in the control area. In Fiordland, New Zealand, two populations (Milford and Doubtful Sounds) of bottlenose dolphins with tourism levels that differed by a factor of seven were observed and significant increases in traveling time and decreases in resting time were documented for both. Consistent short-term avoidance strategies were observed in response to tour boats until a threshold of disturbance was reached (average 68 minutes between interactions), after which the response switched to a longer-term habitat displacement strategy. For one population, tourism only occurred in a part of the home range. However, tourism occurred throughout the home range of the Doubtful Sound population and once boat traffic increased beyond the 68-minute threshold (resulting in abandonment of their home range/preferred habitat), reproductive success drastically decreased (increased stillbirths) and abundance decreased significantly (from 67 to 56 individuals in a short period).

In order to understand how the effects of activities may or may not impact species and stocks of marine mammals, it is necessary to understand not only what the likely disturbances are going to be but how those disturbances may affect the reproductive success and survivorship of individuals and then how those impacts to individuals translate to population-level effects. Following on the earlier work of a committee of the U.S. National Research Council (NRC, 2005), New et al. (2014), in an effort termed the Potential Consequences of Disturbance (PCoD), outline an updated conceptual model of the relationships linking disturbance to changes in behavior and physiology, health, vital rates, and population dynamics. This framework is a four-step process progressing from changes in individual behavior and/or physiology, to changes in individual health, then vital rates, and finally to population-level effects. In this framework, behavioral and physiological changes can have direct (acute) effects on vital rates, such as when changes in habitat use or increased stress levels raise the probability of mother-calf separation or predation; indirect and long-term (chronic) effects on vital rates, such as when changes in time/energy budgets or increased disease susceptibility affect health, which then affects vital rates; or no effect to vital rates (New et al., 2014).

Since the PCoD general framework was outlined and the relevant supporting literature compiled, multiple studies developing state-space energetic models for species with extensive long-term monitoring ( e.g., southern elephant seals, North Atlantic right whales, Ziphiidae beaked whales, and bottlenose dolphins) have been conducted and can be used to effectively forecast longer-term, population-level impacts from behavioral changes. While these are very specific models with very specific data requirements that cannot yet be applied broadly to project-specific risk assessments for the majority of species, they are a critical first step towards being able to quantify the likelihood of a population level effect. Since New et al. (2014), several publications have described models developed to examine the long-term effects of environmental or anthropogenic disturbance of foraging on various life stages of selected species ( e.g., sperm whale, Farmer et al. (2018); California sea lion, McHuron et al. (2018); blue whale, Pirotta et al. (2018a); humpback whale, Dunlop et al. (2021)). These models continue to add to refinement of the approaches to the PCoD framework. Such models also help identify what data inputs require further investigation. Pirotta et al. (2018b) provides a review of the PCoD framework with details on each step of the process and approaches to applying real data or simulations to achieve each step.

Despite its simplicity, there are few complete PCoD models available for any marine mammal species due to a lack of data available to parameterize many of the steps. To date, no PCoD model has been fully parameterized with empirical data (Pirotta et al., 2018a) due to the fact they are data intensive and logistically challenging to complete. Therefore, most complete PCoD models include simulations, theoretical modeling, and expert opinion to move through the steps. For example, PCoD models have been developed to evaluate the effect of wind farm construction on the North Sea harbor porpoise populations ( e.g., King et al., 2015; Nabe-Nielsen et al., 2018). These models include a mix of empirical data, expert elicitation (King et al., 2015) and simulations of animals' movements, energetics, and/or survival (New et al., 2014; Nabe-Nielsen et al., 2018).

PCoD models may also be approached in different manners. Dunlop et al. (2021) modeled migrating humpback whale mother-calf pairs in response to seismic surveys using both a forwards and backwards approach. While a typical forwards approach can determine if a stressor would have population-level consequences, Dunlop et al. demonstrated that working backwards through a PCoD model can be used to assess the “worst case” scenario for an interaction of a target species and stressor. This method may be useful for future management goals when appropriate data becomes available to fully support the model. In another example, harbor porpoise PCoD model investigating the impact of seismic surveys on harbor porpoise included an investigation on underlying drivers of vulnerability. Harbor porpoise movement and foraging were modeled for baseline periods and then for periods with seismic surveys as well; the models demonstrated that temporal ( i.e., seasonal) variation in individual energetics and their link to costs associated with disturbances was key in predicting population impacts (Gallagher et al., 2021).

Behavioral change, such as disturbance manifesting in lost foraging time, in response to anthropogenic activities is often assumed to indicate a biologically significant effect on a population of concern. However, as described above, individuals may be able to compensate for some types and degrees of shifts in behavior, preserving their health and thus their vital rates and population dynamics. For example, New et al. (2013) developed a model simulating the complex social, spatial, behavioral and motivational interactions of coastal bottlenose dolphins in the Moray Firth, Scotland, to assess the biological significance of increased rate of behavioral disruptions caused by vessel traffic. Despite a modeled scenario in which vessel traffic increased from 70 to 470 vessels a year (a 6-fold increase in vessel traffic) in response to the construction of a proposed offshore renewables' facility, the dolphins' behavioral time budget, spatial distribution, motivations, and social structure remain unchanged. Similarly, two bottlenose dolphin populations in Australia were also modeled over 5 years against a number of disturbances (Reed et al., 2020), and results indicated that habitat/noise disturbance had little overall impact on population abundances in either location, even in the most extreme impact scenarios modeled.

By integrating different sources of data ( e.g., controlled exposure data, activity monitoring, telemetry tracking, and prey sampling) into a theoretical model to predict effects from sonar on a blue whale's daily energy intake, Pirotta et al. (2021) found that tagged blue whales' activity budgets, lunging rates, and ranging patterns caused variability in their predicted cost of disturbance. This method may be useful for future management goals when appropriate data becomes available to fully support the model. Harbor porpoise movement and foraging were modeled for baseline periods and then for periods with seismic surveys as well; the models demonstrated that the seasonality of the seismic activity was an important predictor of impact (Gallagher et al., 2021).

In Table 1 of Keen et al. (2021), the authors summarize the emerging themes in PCoD models that should be considered when assessing the likelihood and duration of exposure and the sensitivity of a population to disturbance (see Table 1 from Keen et al., 2021, below). The themes are categorized by life history traits (movement ecology, life history strategy, body size, and pace of life), disturbance source characteristics (overlap with biologically important areas, duration and frequency, and nature and context), and environmental conditions (natural variability in prey availability and climate change). Keen et al. (2021) then summarize how each of these features influence an assessment, noting, for example, that individual animals with small home ranges have a higher likelihood of prolonged or year-round exposure, that the effect of disturbance is strongly influenced by whether it overlaps with biologically important habitats when individuals are present, and that continuous disruption will have a greater impact than intermittent disruption.

Nearly all PCoD studies and experts agree that infrequent exposures of a single day or less are unlikely to impact individual fitness, let alone lead to population level effects (Booth et al., 2016; Booth et al., 2017; Christiansen and Lusseau 2015; Farmer et al., 2018; Wilson et al., 2020; Harwood and Booth 2016; King et al., 2015; McHuron et al., 2018; National Academies of Sciences, Engineering, and Medicine (NAS), 2017; New et al., 2014; Pirotta et al., 2018a; Southall et al., 2007; Villegas-Amtmann et al., 2015). As described through this proposed rule, NMFS expects that any behavioral disturbance that would occur due to animals being exposed to construction activity would be of a relatively short duration, with behavior returning to a baseline state shortly after the acoustic stimuli ceases or the animal moves far enough away from the source. Given this, and NMFS' evaluation of the available PCoD studies, and the required mitigation discussed later, any such behavioral disturbance resulting from Atlantic Shores' activities is not expected to impact individual animals' health or have effects on individual animals' survival or reproduction, thus no detrimental impacts at the population level are anticipated. Marine mammals may temporarily avoid the immediate area but are not expected to permanently abandon the area or their migratory or foraging behavior. Impacts to breeding, feeding, sheltering, resting, or migration are not expected nor are shifts in habitat use, distribution, or foraging success.

Potential Effects From Vessel Strike

Vessel collisions with marine mammals, also referred to as vessel strikes or ship strikes, can result in death or serious injury of the animal. Wounds resulting from vessel strike may include massive trauma, hemorrhaging, broken bones, or propeller lacerations (Knowlton and Kraus, 2001). An animal at the surface could be struck directly by a vessel, a surfacing animal could hit the bottom of a vessel, or an animal just below the surface could be cut by a vessel's propeller. Superficial strikes may not kill or result in the death of the animal. Lethal interactions are typically associated with large whales, which are occasionally found draped across the bulbous bow of large commercial ships upon arrival in port. Although smaller cetaceans are more maneuverable in relation to large vessels than are large whales, they may also be susceptible to strike. The severity of injuries typically depends on the size and speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007; Conn and Silber, 2013). Impact forces increase with speed, as does the probability of a strike at a given distance (Silber et al., 2010; Gende et al., 2011).

The most vulnerable marine mammals are those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives ( e.g., the sperm whale). In addition, some baleen whales seem generally unresponsive to vessel sound, making them more susceptible to vessel collisions (Nowacek et al., 2004). These species are primarily large, slow moving whales. Marine mammal responses to vessels may include avoidance and changes in dive pattern (NRC, 2003).

An examination of all known vessel strikes from all shipping sources (civilian and military) indicates vessel speed is a principal factor in whether a vessel strike occurs and, if so, whether it results in injury, serious injury, or mortality (Knowlton and Kraus, 2001; Laist et al., 2001; Jensen and Silber, 2003; Pace and Silber, 2005; Vanderlaan and Taggart, 2007; Conn and Silber, 2013). In assessing records in which vessel speed was known, Laist et al. (2001) found a direct relationship between the occurrence of a whale strike and the speed of the vessel involved in the collision. The authors concluded that most deaths occurred when a vessel was traveling in excess of 13 kn (34.52 mph).

Jensen and Silber (2003) detailed 292 records of known or probable vessel strikes of all large whale species from 1975 to 2002. Of these, vessel speed at the time of collision was reported for 58 cases. Of these 58 cases, 39 (or 67 percent) resulted in serious injury or death (19 of those resulted in serious injury as determined by blood in the water, propeller gashes or severed tailstock, and fractured skull, jaw, vertebrae, hemorrhaging, massive bruising or other injuries noted during necropsy and 20 resulted in death). Operating speeds of vessels that struck various species of large whales ranged from 2 to 51 kn (2.3 to 58.68 mph). The majority (79 percent) of these strikes occurred at speeds of 13 kn (34.52 mph) or greater. The average speed that resulted in serious injury or death was 18.6 kn (21.4 mph). Pace and Silber (2005) found that the probability of death or serious injury increased rapidly with increasing vessel speed. Specifically, the predicted probability of serious injury or death increased from 45 to 75 percent as vessel speed increased from 10 to 14 kn (11.51 to 16.11 mph) and exceeded 90 percent at 17 kn (19.56 mph). Higher speeds during collisions result in greater force of impact and also appear to increase the chance of severe injuries or death. While modeling studies have suggested that hydrodynamic forces pulling whales toward the vessel hull increase with increasing speed (Clyne, 1999; Knowlton et al., 1995), this is inconsistent with Silber et al. (2010), which demonstrated that there is no such relationship ( i.e., hydrodynamic forces are independent of speed).

In a separate study, Vanderlaan and Taggart (2007) analyzed the probability of lethal mortality of large whales at a given speed, showing that the greatest rate of change in the probability of a lethal injury to a large whale as a function of vessel speed occurs between 8.6 and 15 kn (17.26 mph). The chances of a lethal injury decline from approximately 80 percent at 15 kn to approximately 20 percent at 8.6 kn (9.9 mph). At speeds below 11.8 kn (13.58 mph), the chances of lethal injury drop below 50 percent, while the probability asymptotically increases toward 100 percent above 15 kn (17.26 mph).

The Jensen and Silber (2003) report notes that the Large Whale Ship Strike Database represents a minimum number of collisions, because the vast majority probably goes undetected or unreported. In contrast, the project's personnel are likely to detect any strike that does occur because of the required personnel training and lookouts, along with the inclusion of Protected Species Observers (as described in the Proposed Mitigation section), and they are required to report all ship strikes involving marine mammals.

There are no known vessel strikes of marine mammals by any offshore wind energy vessel in the U.S. Given the extensive mitigation and monitoring measures (see the Proposed Mitigation and Proposed Monitoring and Reporting section) that would be required of Atlantic Shores, NMFS believes that a vessel strike is not likely to occur.

Potential Effects to Marine Mammal Habitat

Atlantic Shores' proposed activities could potentially affect marine mammal habitat through the introduction of impacts to the prey species of marine mammals (through noise, oceanographic processes, or reef effects), acoustic habitat (sound in the water column), water quality, and biologically important habitat for marine mammals.

Effects on Prey

Sound may affect marine mammals through impacts on the abundance, behavior, or distribution of prey species ( e.g., crustaceans, cephalopods, fish, and zooplankton). Marine mammal prey varies by species, season, and location and, for some, is not well documented. Here, we describe studies regarding the effects of noise on known marine mammal prey.

Fish utilize the soundscape and components of sound in their environment to perform important functions such as foraging, predator avoidance, mating, and spawning ( e.g., Zelick and Mann, 1999; Fay, 2009). The most likely effects on fishes exposed to loud, intermittent, low-frequency sounds are behavioral responses ( i.e., flight or avoidance). Short duration, sharp sounds (such as pile driving or airguns) can cause overt or subtle changes in fish behavior and local distribution. The reaction of fish to acoustic sources depends on the physiological state of the fish, past exposures, motivation ( e.g., feeding, spawning, migration), and other environmental factors. Key impacts to fishes may include behavioral responses, hearing damage, barotrauma (pressure-related injuries), and mortality. While it is clear that the behavioral responses of individual prey, such as displacement or other changes in distribution, can have direct impacts on the foraging success of marine mammals, the effects on marine mammals of individual prey that experience hearing damage, barotrauma, or mortality is less clear, though obviously population scale impacts that meaningfully reduce the amount of prey available could have more serious impacts.

Fishes, like other vertebrates, have a variety of different sensory systems to glean information from ocean around them (Astrup and Mohl, 1993; Astrup, 1999; Braun and Grande, 2008; Carroll et al., 2017; Hawkins and Johnstone, 1978; Ladich and Popper, 2004; Ladich and Schulz-Mirbach, 2016; Mann, 2016; Nedwell et al., 2004; Popper et al., 2003; Popper et al., 2005). Depending on their hearing anatomy and peripheral sensory structures, which vary among species, fishes hear sounds using pressure and particle motion sensitivity capabilities and detect the motion of surrounding water (Fay et al., 2008) (terrestrial vertebrates generally only detect pressure). Most marine fishes primarily detect particle motion using the inner ear and lateral line system while some fishes possess additional morphological adaptations or specializations that can enhance their sensitivity to sound pressure, such as a gas-filled swim bladder (Braun and Grande, 2008; Popper and Fay, 2011).

Hearing capabilities vary considerably between different fish species with data only available for just over 100 species out of the 34,000 marine and freshwater fish species (Eschmeyer and Fong, 2016). In order to better understand acoustic impacts on fishes, fish hearing groups are defined by species that possess a similar continuum of anatomical features, which result in varying degrees of hearing sensitivity (Popper and Hastings, 2009a). There are four hearing groups defined for all fish species (modified from Popper et al., 2014) within this analysis, and they include: fishes without a swim bladder ( e.g., flatfish, sharks, rays, etc.); fishes with a swim bladder not involved in hearing ( e.g., salmon, cod, pollock, etc.); fishes with a swim bladder involved in hearing ( e.g., sardines, anchovy, herring, etc.); and fishes with a swim bladder involved in hearing and high-frequency hearing ( e.g., shad and menhaden). Most marine mammal fish prey species would not be likely to perceive or hear mid- or high-frequency sonars. While hearing studies have not been done on sardines and northern anchovies, it would not be unexpected for them to have hearing similarities to Pacific herring (up to 2–5 kHz) (Mann et al., 2005). Currently, less data are available to estimate the range of best sensitivity for fishes without a swim bladder.

In terms of physiology, multiple scientific studies have documented a lack of mortality or physiological effects to fish from exposure to low- and mid-frequency sonar and other sounds (Halvorsen et al., 2012a; Jørgensen et al., 2005; Juanes et al., 2017; Kane et al., 2010; Kvadsheim and Sevaldsen, 2005; Popper et al., 2007; Popper et al., 2016; Watwood et al., 2016). Techer et al. (2017) exposed carp in floating cages for up to 30 days to low-power 23 and 46 kHz source without any significant physiological response. Other studies have documented either a lack of TTS in species whose hearing range cannot perceive sonar (such as Navy sonar), or for those species that could perceive sonar-like signals, any TTS experienced would be recoverable (Halvorsen et al., 2012a; Ladich and Fay, 2013; Popper and Hastings, 2009a, 2009b; Popper et al., 2014; Smith, 2016). Only fishes that have specializations that enable them to hear sounds above about 2,500 Hz (2.5 kHz), such as herring (Halvorsen et al., 2012a; Mann et al., 2005; Mann, 2016; Popper et al., 2014), would have the potential to receive TTS or exhibit behavioral responses from exposure to mid-frequency sonar. In addition, any sonar induced TTS to fish whose hearing range could perceive sonar would only occur in the narrow spectrum of the source ( e.g., 3.5 kHz) compared to the fish's total hearing range ( e.g., 0.01 kHz to 5 kHz).

In terms of behavioral responses, Juanes et al. (2017) discuss the potential for negative impacts from anthropogenic noise on fish, but the author's focus was on broader based sounds, such as ship and boat noise sources. Watwood et al. (2016) also documented no behavioral responses by reef fish after exposure to mid-frequency active sonar. Doksaeter et al. (2009; 2012) reported no behavioral responses to mid-frequency sonar (such as naval sonar) by Atlantic herring; specifically, no escape reactions (vertically or horizontally) were observed in free swimming herring exposed to mid-frequency sonar transmissions. Based on these results (Doksaeter et al., 2009; Doksaeter et al., 2012; Sivle et al., 2012), Sivle et al. (2014) created a model in order to report on the possible population-level effects on Atlantic herring from active sonar. The authors concluded that the use of sonar poses little risk to populations of herring regardless of season, even when the herring populations are aggregated and directly exposed to sonar. Finally, Bruintjes et al. (2016) commented that fish exposed to any short-term noise within their hearing range might initially startle, but would quickly return to normal behavior.

Pile-driving noise during construction is of particular concern as the very high sound pressure levels could potentially prevent fish from reaching breeding or spawning sites, finding food, and acoustically locating mates. A playback study in West Scotland revealed that there was a significant movement response to the pile-driving stimulus in both species at relatively low received sound pressure levels (sole: 144 to 156 dB re 1μPa Peak; cod: 140 to 161 dB re 1 μPa Peak, particle motion between 6.51 x 10³ and 8.62 x 10⁴ m/s² peak) (Mueller-Blenkle et al., 2010). The swimming speed of the sole increased significantly during the playback of construction noise when compared to the playbacks of before and after construction. While not statistically significant, cod also displayed a similar behavioral response during before, during, and after construction playbacks. However, cod demonstrated a specific and significant freezing response at the onset and cessation of the playback recording. In both species, indications were present displaying directional movements away from the playback source. During wind farm construction in the Eastern Taiwan Strait, Type 1 soniferous fish chorusing showed a relatively lower intensity and longer duration while Type 2 chorusing exhibited higher intensity and no changes in its duration. Deviation from regular fish vocalization patterns may affect fish reproductive success, cause migration, augmented predation, or physiological alterations.

Occasional behavioral reactions to activities that produce underwater noise sources are unlikely to cause long-term consequences for individual fish or populations. The most likely impact to fish from impact and vibratory pile driving activities at the Project Areas would be temporary behavioral avoidance of the area. Any behavioral avoidance by fish of the disturbed area would still leave significantly large areas of fish and marine mammal foraging habitat in the nearby vicinity. The duration of fish avoidance of an area after pile driving stops is unknown, but a rapid return to normal recruitment, distribution and behavior is anticipated. In general, impacts to marine mammal prey species are expected to be minor and temporary due to the expected short daily duration of individual pile driving events and the relatively small areas being affected.

SPLs of sufficient strength have been known to cause fish auditory impairment, injury and mortality. Popper et al. (2014) found that fish with or without air bladders could experience TTS at 186 dB SEL_cum . Mortality could occur for fish without swim bladders at >216 dB SEL_cum . Those with swim bladders or at the egg or larvae life stage, mortality was possible at >203 dB SEL_cum . Other studies found that 203 dB SEL_cum or above caused a physiological response in other fish species (Casper et al., 2012, Halvorsen et al., 2012a, Halvorsen et al., 2012b, Casper et al., 2013a; Casper et al., 2013b). However, in most fish species, hair cells in the ear continuously regenerate and loss of auditory function likely is restored when damaged cells are replaced with new cells. Halvorsen et al. (2012a) showed that a TTS of 4–6 dB was recoverable within 24 hours for one species. Impacts would be most severe when the individual fish is close to the source and when the duration of exposure is long. Injury caused by barotrauma can range from slight to severe and can cause death, and is most likely for fish with swim bladders. Barotrauma injuries have been documented during controlled exposure to impact pile driving (Halvorsen et al., 2012b; Casper et al., 2013).

As described in the Proposed Mitigation section below, Atlantic Shores would utilize a sound attenuation device which would reduce potential for injury to marine mammal prey. Other fish that experience hearing loss as a result of exposure to impulsive sound sources may have a reduced ability to detect relevant sounds such as predators, prey, or social vocalizations. However, PTS has not been known to occur in fishes and any hearing loss in fish may be as temporary as the timeframe required to repair or replace the sensory cells that were damaged or destroyed (Popper et al., 2005; Popper et al., 2014; Smith et al., 2006). It is not known if damage to auditory nerve fibers could occur, and if so, whether fibers would recover during this process.

Several studies have demonstrated that airgun sounds might affect the distribution and behavior of some fishes, potentially impacting foraging opportunities or increasing energetic costs ( e.g., Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999; Paxton et al., 2017). Required soft-starts would allow prey and marine mammals to move away from the source prior to any noise levels that may physically injure prey and the use of the noise attenuation devices would reduce noise levels to the degree any mortality or injury of prey is also minimized. Use of bubble curtains, in addition to reducing impacts to marine mammals, for example, is a key mitigation measure in reducing injury and mortality of ESA-listed salmon on the U.S. West Coast. However, we recognize some mortality, physical injury and hearing impairment in marine mammal prey may occur, but we anticipate the amount of prey impacted in this manner is minimal compared to overall availability. Any behavioral responses to pile driving by marine mammal prey are expected to be brief. We expect that other impacts, such as stress or masking, would occur in fish that serve as marine mammal prey (Popper et al., 2019). However, those impacts would be limited to the duration of impact pile driving and if prey were to move out the area in response to noise, these impacts would be minimized.

In addition to fish, prey sources such as marine invertebrates could potentially be impacted by noise stressors as a result of the proposed activities. However, most marine invertebrates' ability to sense sounds is limited. Invertebrates appear to be able to detect sounds (Pumphrey, 1950; Frings and Frings, 1967) and are most sensitive to low-frequency sounds (Packard et al., 1990; Budelmann and Williamson, 1994; Lovell et al., 2005; Mooney et al., 2010). Data on response of invertebrates such as squid, another marine mammal prey species, to anthropogenic sound is more limited (de Soto, 2016; Sole et al., 2017). Data suggest that cephalopods are capable of sensing the particle motion of sounds and detect low frequencies up to 1–1.5 kHz, depending on the species, and so are likely to detect airgun noise (Kaifu et al., 2008; Hu et al., 2009; Mooney et al., 2010; Samson et al., 2014). Sole et al. (2017) reported physiological injuries to cuttlefish in cages placed at-sea when exposed during a controlled exposure experiment to low-frequency sources (315 Hz, 139 to 142 dB re 1 μPa ² and 400 Hz, 139 to 141 dB re 1 μPa ² ). Fewtrell and McCauley (2012) reported squids maintained in cages displayed startle responses and behavioral changes when exposed to seismic airgun sonar (136–162 re 1 μPa² ·s). Jones et al. (2020) found that when squid ( Doryteuthis pealeii) were exposed to impulse pile driving noise, body pattern changes, inking, jetting, and startle responses were observed and nearly all squid exhibited at least one response. However, these responses occurred primarily during the first eight impulses and diminished quickly, indicating potential rapid, short-term habituation.

Cephalopods have a specialized sensory organ inside the head called a statocyst that may help an animal determine its position in space (orientation) and maintain balance (Budelmann, 1992). Packard et al. (1990) showed that cephalopods were sensitive to particle motion, not sound pressure, and Mooney et al. (2010) demonstrated that squid statocysts act as an accelerometer through which particle motion of the sound field can be detected. Auditory injuries (lesions occurring on the statocyst sensory hair cells) have been reported upon controlled exposure to low-frequency sounds, suggesting that cephalopods are particularly sensitive to low-frequency sound (Andre et al., 2011; Sole et al., 2013). Behavioral responses, such as inking and jetting, have also been reported upon exposure to low-frequency sound (McCauley et al., 2000; Samson et al., 2014). Squids, like most fish species, are likely more sensitive to low frequency sounds and may not perceive mid- and high-frequency sonars.

With regard to potential impacts on zooplankton, McCauley et al. (2017) found that exposure to airgun noise resulted in significant depletion for more than half the taxa present and that there were two to three times more dead zooplankton after airgun exposure compared with controls for all taxa, within 1 km of the airguns. However, the authors also stated that in order to have significant impacts on r-selected species ( i.e., those with high growth rates and that produce many offspring) such as plankton, the spatial or temporal scale of impact must be large in comparison with the ecosystem concerned, and it is possible that the findings reflect avoidance by zooplankton rather than mortality (McCauley et al., 2017). In addition, the results of this study are inconsistent with a large body of research that generally finds limited spatial and temporal impacts to zooplankton as a result of exposure to airgun noise ( e.g., Dalen and Knutsen, 1987; Payne, 2004; Stanley et al., 2011). Most prior research on this topic, which has focused on relatively small spatial scales, has showed minimal effects ( e.g., Kostyuchenko, 1973; Booman et al., 1996; Sætre and Ona, 1996; Pearson et al., 1994; Bolle et al., 2012).

A modeling exercise was conducted as a follow-up to the McCauley et al. (2017) study (as recommended by McCauley et al.), in order to assess the potential for impacts on ocean ecosystem dynamics and zooplankton population dynamics (Richardson et al., 2017). Richardson et al. (2017) found that a full-scale airgun survey would impact copepod abundance within the survey area, but that effects at a regional scale were minimal (2 percent decline in abundance within 150 km of the survey area and effects not discernible over the full region). The authors also found that recovery within the survey area would be relatively quick (3 days following survey completion), and suggest that the quick recovery was due to the fast growth rates of zooplankton, and the dispersal and mixing of zooplankton from both inside and outside of the impacted region. The authors also suggest that surveys in areas with more dynamic ocean circulation in comparison with the study region and/or with deeper waters ( i.e., typical offshore wind locations) would have less net impact on zooplankton.

Notably, a recently described study produced results inconsistent with those of McCauley et al. (2017). Researchers conducted a field and laboratory study to assess if exposure to airgun noise affects mortality, predator escape response, or gene expression of the copepod Calanus finmarchicus (Fields et al., 2019). Immediate mortality of copepods was significantly higher, relative to controls, at distances of 5 m or less from the airguns. Mortality 1 week after the airgun blast was significantly higher in the copepods placed 10 m from the airgun but was not significantly different from the controls at a distance of 20 m from the airgun. The increase in mortality, relative to controls, did not exceed 30 percent at any distance from the airgun. Moreover, the authors caution that even this higher mortality in the immediate vicinity of the airguns may be more pronounced than what would be observed in free-swimming animals due to increased flow speed of fluid inside bags containing the experimental animals. There were no sub-lethal effects on the escape performance or the sensory threshold needed to initiate an escape response at any of the distances from the airgun that were tested. Whereas McCauley et al. (2017) reported an SEL of 156 dB at a range of 509–658 m, with zooplankton mortality observed at that range, Fields et al. (2019) reported an SEL of 186 dB at a range of 25 m, with no reported mortality at that distance.

The presence of large numbers of turbines has been shown to impact meso- and sub-meso-scale water column circulation, which can affect the density, distribution, and energy content of zooplankton and thereby, their availability as marine mammal prey. Topside, atmospheric wakes result in wind speed reductions influencing upwelling and downwelling in the ocean while underwater structures such as WTG, OSS, and Met tower foundations may cause turbulent current wakes, which impact circulation, stratification, mixing, and sediment resuspension (Daewel et al., 2022). Overall, the presence and operation of structures such as wind turbines are, in general, likely to result in local and broader oceanographic effects in the marine environment and may disrupt marine mammal prey, such as dense aggregations and distribution of zooplankton through altering the strength of tidal currents and associated fronts, changes in stratification, primary production, the degree of mixing, and stratification in the water column (Chen et al., 2021; Johnson et al., 2021; Christiansen et al., 2022; Dorrell et al., 2022). However, the scale of impacts is difficult to predict and may vary from meters to hundreds of meters for local individual turbine impacts (Schultze et al., 2020) to large-scale dipoles of surface elevation changes stretching hundreds of kilometers (Christiansen et al., 2022).

Atlantic Shores intends to install up to 200 WTGs, up to 10 OSSs, and 1 Met Tower. Turbine operations would commence in 2028 (Project 1) and 2029 (Project 2), with all turbines being operational in 2029. As described above, there is scientific uncertainty around the scale of oceanographic impacts (meters to kilometers) associated with turbine operation. The project is located offshore of New Jersey, within a migratory BIA for North Atlantic right whales. Although right whales and humpback whales have been observed feeding off the New Jersey coast (Whitt et al., 2013; Whitt et al., 2015), the majority of whales are expected to be moving through the area. In addition, seasonal pile driving restrictions from January through April will reduce the potential for overlap between construction activities and any foraging whales.

Potential impacts on prey could impact the distribution of marine mammals within the Project Area, potentially necessitating additional energy expenditure to find and capture prey, but at the temporal and spatial scales anticipated for this activity are not expected to impact the reproduction or survival of any individual marine mammals. Although studies assessing the impacts of offshore wind development on marine mammals are limited, the repopulation of wind energy areas by harbor porpoises (Brandt et al., 2016; Lindeboom et al., 2011) and harbor seals (Lindeboom et al., 2011; Russell et al., 2016) following the installation of wind turbines are promising. Overall, any impacts to marine mammal foraging capabilities due to effects on prey aggregation from the turbine presence and operation during the effective period of the proposed rule is likely to be limited. As the nearest North Atlantic right whale feeding BIA and humpback whale feeding BIA are approximately 419.1 km away from the proposed Project Area, these areas would likely be unaffected by the project's operation.

In general, impacts to marine mammal prey species are expected to be relatively minor and temporary due to the expected short daily duration of individual pile driving events and the relatively small areas being affected. NMFS does not expect HRG acoustic sources to impact fish and most sources are likely outside the hearing range of the primary prey species in the Project Area. Prey species exposed to sound might move away from the sound source, experience TTS, experience masking of biologically relevant sounds, or show no obvious direct effects. Overall, however, the combined impacts of sound exposure, water quality, and oceanographic impacts on marine mammal habitat resulting from the proposed activities would not be expected to have measurable effects on populations of marine mammal prey species.

Reef Effects

The presence of monopile foundations, scour protection, and cable protection will result in a conversion of the existing sandy bottom habitat to a hard bottom habitat with areas of vertical structural relief. This could potentially alter the existing habitat by creating an “artificial reef effect” that results in colonization by assemblages of both sessile and mobile animals within the new hard-bottom habitat (Wilhelmsson et al., 2006; Reubens et al., 2013; Bergström et al., 2014; Coates et al., 2014). This colonization by marine species, especially hard-substrate preferring species, can result in changes to the diversity, composition, and/or biomass of the area thereby impacting the trophic composition of the site (Wilhelmsson et al., 2010, Krone et al., 2013; Bergström et al., 2014, Hooper et al., 2017; Raoux et al., 2017; Harrison and Rousseau, 2020; Taormina et al., 2020; Buyse et al., 2022a; ter Hofstede et al., 2022).

Artificial structures can create increased habitat heterogeneity important for species diversity and density (Langhamer, 2012). The WTG and OSS foundations will extend through the water column, which may serve to increase settlement of meroplankton or planktonic larvae on the structures in both the pelagic and benthic zones (Boehlert and Gill, 2010). Fish and invertebrate species are also likely to aggregate around the foundations and scour protection which could provide increased prey availability and structural habitat (Boehlert and Gill, 2010; Bonar et al., 2015). Further, instances of species previously unknown, rare, or nonindigenous to an area have been documented at artificial structures, changing the composition of the food web and possibly the attractability of the area to new or existing predators (Adams et al., 2014; de Mesel, 2015; Bishop et al., 2017; Hooper et al., 2017; Raoux et al., 2017; van Hal et al., 2017; Degraer et al., 2020; Fernandez-Betelu et al., 2022). Notably, there are examples of these sites becoming dominated by marine mammal prey species, such as filter-feeding species and suspension-feeding crustaceans (Andersson and Öhman, 2010; Slavik et al., 2019; Hutchison et al., 2020; Pezy et al., 2020; Mavraki et al., 2022).

Numerous studies have documented significantly higher fish concentrations including species like cod and pouting ( Trisopterus luscus), flounder ( Platichthys flesus), eelpout ( Zoarces viviparus), and eel ( Anguilla anguilla) near in-water structures than in surrounding soft bottom habitat (Langhamer and Wilhelmsson, 2009; Bergström et al., 2013; Reubens et al., 2013). In the German Bight portion of the North Sea, fish were most densely congregated near the anchorages of jacket foundations, and the structures extending through the water column were thought to make it more likely that juvenile or larval fish encounter and settle on them (Rhode Island Coastal Resources Management Council (RI–CRMC), 2010; Krone et al., 2013). In addition, fish can take advantage of the shelter provided by these structures while also being exposed to stronger currents created by the structures, which generate increased feeding opportunities and decreased potential for predation (Wilhelmsson et al., 2006). The presence of the foundations and resulting fish aggregations around the foundations is expected to be a long-term habitat impact, but the increase in prey availability could potentially be beneficial for some marine mammals.

The most likely impact to marine mammal habitat from the project is expected to be from pile driving, which may affect marine mammal food sources such as forage fish and could also cause acoustic habitat effects on marine mammal prey ( e.g., fish).

Water Quality

Temporary and localized reduction in water quality will occur as a result of in-water construction activities. Most of this effect will occur during pile driving and installation of the cables, including auxiliary work such as dredging and scour placement. These activities will disturb bottom sediments and may cause a temporary increase in suspended sediment in the Project Area. Currents should quickly dissipate any raised total suspended sediment (TSS) levels, and levels should return to background levels once the project activities in that area cease. No direct impacts on marine mammals is anticipated due to increased TSS and turbidity; however, turbidity within the water column has the potential to reduce the level of oxygen in the water and irritate the gills of prey fish species in the proposed Project Area. However, turbidity plumes associated with the project would be temporary and localized, and fish in the proposed Project Area would be able to move away from and avoid the areas where plumes may occur. Therefore, it is expected that the impacts on prey fish species from turbidity, and therefore on marine mammals, would be minimal and temporary.

Equipment used by Atlantic Shores within the Project Area, including ships and other marine vessels, potentially aircrafts, and other equipment, are also potential sources of by-products ( e.g., hydrocarbons, particulate matter, heavy metals). All equipment is properly maintained in accordance with applicable legal requirements. All such operating equipment meets Federal water quality standards, where applicable. Given these requirements, impacts to water quality are expected to be minimal.

Acoustic Habitat

Acoustic habitat is the soundscape, which encompasses all of the sound present in a particular location and time, as a whole when considered from the perspective of the animals experiencing it. Animals produce sound for, or listen for sounds produced by, conspecifics (communication during feeding, mating, and other social activities), other animals (finding prey or avoiding predators), and the physical environment (finding suitable habitats, navigating). Together, sounds made by animals and the geophysical environment ( e.g., produced by earthquakes, lightning, wind, rain, waves) make up the natural contributions to the total acoustics of a place. These acoustic conditions, termed acoustic habitat, are one attribute of an animal's total habitat.

Soundscapes are also defined by, and acoustic habitat influenced by, the total contribution of anthropogenic sound. This may include incidental emissions from sources such as vessel traffic or may be intentionally introduced to the marine environment for data acquisition purposes (as in the use of airgun arrays) or for Navy training and testing purposes (as in the use of sonar and explosives and other acoustic sources). Anthropogenic noise varies widely in its frequency, content, duration, and loudness and these characteristics greatly influence the potential habitat-mediated effects to marine mammals (please also see the previous discussion on Masking), which may range from local effects for brief periods of time to chronic effects over large areas and for long durations. Depending on the extent of effects to habitat, animals may alter their communications signals (thereby potentially expending additional energy) or miss acoustic cues (either conspecific or adventitious). Problems arising from a failure to detect cues are more likely to occur when noise stimuli are chronic and overlap with biologically relevant cues used for communication, orientation, and predator/prey detection (Francis and Barber, 2013). For more detail on these concepts, see Barber et al., 2009; Pijanowski et al., 2011; Francis and Barber, 2013; Lillis et al., 2014.

The term “listening area” refers to the region of ocean over which sources of sound can be detected by an animal at the center of the space. Loss of communication space concerns the area over which a specific animal signal, used to communicate with conspecifics in biologically important contexts ( e.g., foraging, mating), can be heard, in noisier relative to quieter conditions (Clark et al., 2009). Lost listening area concerns the more generalized contraction of the range over which animals would be able to detect a variety of signals of biological importance, including eavesdropping on predators and prey (Barber et al., 2009). Such metrics do not, in and of themselves, document fitness consequences for the marine animals that live in chronically noisy environments. Long-term population-level consequences mediated through changes in the ultimate survival and reproductive success of individuals are difficult to study, and particularly so underwater. However, it is increasingly well documented that aquatic species rely on qualities of natural acoustic habitats, with researchers quantifying reduced detection of important ecological cues ( e.g., Francis and Barber, 2013; Slabbekoorn et al., 2010) as well as survivorship consequences in several species ( e.g., Simpson et al., 2014; Nedelec et al., 2014).

Sound produced from construction activities in the Project Area would be temporary and transitory. The sounds produced during construction activities may be widely dispersed or concentrated in small areas for varying periods. Any anthropogenic noise attributed to construction activities in the Project Area would be temporary and the affected area would be expected to immediately return to the original state when these activities cease.

Although this proposed rulemaking primarily covers the noise produced from construction activities relevant to this offshore wind facility, operational noise was a consideration in NMFS' analysis of the project, as all turbines would become operational within the effective dates of the rule (if issued). It is expected that all turbines would be operational by 2029. Once operational, offshore wind turbines are known to produce continuous, non-impulsive underwater noise, primarily below 1 kHz (Tougaard et al., 2020; Stöber and Thomsen, 2021).

In both newer, quieter, direct-drive systems (such as what has been proposed for use in the project) and older generation, geared turbine designs, recent scientific studies indicate that operational noise from turbines is on the order of 110 to 125 dB re 1 μPa root-mean-square sound pressure level (SPL_rms) at an approximate distance of 50 m (Tougaard et al., 2020). Recent measurements of operational sound generated from wind turbines (direct drive, 6 MW, jacket piles) at Block Island Wind Farm (BIWF) indicate average broadband levels of 119 dB at 50 m from the turbine, with levels varying with wind speed (HDR, Inc., 2019). Interestingly, measurements from BIWF turbines showed operational sound had less tonal components compared to European measurements of turbines with gear boxes.

Tougaard et al. (2020) further stated that the operational noise produced by WTGs is static in nature and lower than noise produced by passing ships. This is a noise source in this region to which marine mammals are likely already habituated. Furthermore, operational noise levels are likely lower than those ambient levels already present in active shipping lanes, such that operational noise would likely only be detected in very close proximity to the WTG (Thomsen et al., 2006; Tougaard et al., 2020). Similarly, recent measurements from a wind farm (3 MW turbines) in China found at above 300 Hz, turbines produced sound that was similar to background levels (Zhang et al., 2021). Other studies by Jansen and de Jong (2016) and Tougaard et al. (2009) determined that, while marine mammals would be able to detect operational noise from offshore wind farms (again, based on older 2 MW models) for several kilometers, they expected no significant impacts on individual survival, population viability, marine mammal distribution, or the behavior of the animals considered in their study (harbor porpoises and harbor seals).

More recently, Stöber and Thomsen (2021) used monitoring data and modeling to estimate noise generated by more recently developed, larger (10 MW) direct-drive WTGs. Their findings, similar to Tougaard et al. (2020), demonstrate that there is a trend that operational noise increases with turbine size. Their study predicts broadband source levels could exceed 170 dB SPL_rms for a 10 MW WTG. However, those noise levels were generated based on geared turbines; newer turbines operate with direct drive technology. The shift from using gear boxes to direct drive technology is expected to reduce the levels by 10 dB. The findings in the Stöber and Thomsen (2021) study have not been experimentally validated, though the modeling (using largely geared turbines) performed by Tougaard et al. (2020) yields similar results for a hypothetical 10 MW WTG. Overall, noise from operating turbines would raise ambient noise levels in the immediate vicinity of the turbines. However, the spatial extent of increased noise levels would be limited. NMFS proposes to require Atlantic Shores to measure operational noise levels.

In addition, Madsen et al. (2006b) found the intensity of noise generated by operational wind turbines to be much less than the noises present during construction, although this observation was based on a single turbine with a maximum power of 2 MW. Other studies by Jansen and de Jong (2016) and Tougaard et al. (2009) determined that, while marine mammals would be able to detect operational noise from offshore wind farms (again, based on older 2 MW models) for several thousand kilometer, they expected no significant impacts on individual survival, population viability, marine mammal distribution, or the behavior of the animals considered in their study (harbor porpoises and harbor seals).

More recently, Stöber and Thomsen (2021) used monitoring data and modeling to estimate noise generated by more recently developed, larger (10 MW) direct-drive WTGs. Their findings, similar to Tougaard et al. (2020), demonstrate that there is a trend that operational noise increases with turbine size. Their study found noise levels could exceed 170 (to 177 dB re 1 μPa SPL_rms for a 10 MW WTG). However, those noise levels were generated by geared turbines, but newer turbines operate with direct drive technology. The shift from using gear boxes to direct drive technology is expected to reduce the sound level by 10 dB. The findings in the Stöber and Thomsen (2021) study have not been validated. As Atlantic Shores did not request, and NMFS is not proposing to authorize, take incidental to operational noise from WTGs, the topic is not discussed or analyzed further herein.

Estimated Take

This section provides an estimate of the number of incidental takes proposed for authorization under the regulations, which will inform both NMFS' consideration of “small numbers” and the negligible impact determination.

Harassment is the only type of take expected to result from these activities. Except with respect to certain activities not pertinent here, section 3(18) of the MMPA defines “harassment” as any act of pursuit, torment, or annoyance, which has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment) or has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

Authorized takes would primarily be by Level B harassment, as noise from pile driving and HRG surveys could result in behavioral disturbance of marine mammals that qualifies as take. Impacts such as masking and TTS can contribute to the disruption of behavioral patterns and are accounted for within those requested takes. There is also some potential for auditory injury (Level A harassment) of 9 species of marine mammals (including 9 stocks), not including the North Atlantic right whale. However, the amount of Level A harassment that Atlantic Shores requested, and NMFS proposes to authorize, is low. While NMFS is proposing to authorize Level A harassment and Level B harassment, the proposed mitigation and monitoring measures are expected to minimize the amount and severity of such taking to the extent practicable (see Proposed Mitigation and Proposed Monitoring and Reporting).

As described previously, no serious injury or mortality is anticipated or proposed to be authorized incidental to the specified activities. Even without mitigation, both pile driving activities and HRG surveys would not have the potential to directly cause marine mammal mortality or serious injury. While, in general, mortality and serious injury of marine mammals could occur from vessel strikes, the mitigation and monitoring measures contained within this proposed rule are expected to lower the risk of vessel strike such that the risk is discountable (see Proposed Mitigation section). Atlantic Shores has not requested, and NMFS is not authorizing, take by vessel strike. No other activities have the potential to result in mortality or serious injury.

For acoustic impacts, we estimate take by considering: (1) acoustic thresholds above which the best available science indicates marine mammals will be behaviorally harassed or incur some degree of permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and, (4) the number of days of activities. We note that while these factors can contribute to a basic calculation to provide an initial prediction of potential takes, additional information that can qualitatively inform take estimates is also sometimes available ( e.g., previous monitoring results or average group size). Below, we describe the factors considered here in more detail and present the proposed take estimates.

As described below, there are three primary methods ( i.e., density-based, PSO-based, or mean group size) available to predict the amount of harassment that may occur incidental to the proposed project. Alternatively, for each species and activity, the largest value resulting from the three take estimation methods described below was carried forward as the amount of requested take, by Level B harassment. The amount of requested take, by Level A harassment, reflects the density-based exposure estimates and, for some species and activities, consideration of other data such as mean group size.

Below, we describe NMFS' acoustic thresholds, acoustic and exposure modeling methodologies, marine mammal density calculation methodology, occurrence information, and the modeling and methodologies applied to estimate take for each specified activity. NMFS has carefully considered all information and analysis presented by Atlantic Shores, as well as all other applicable information and, based on the best available science, concurs that Atlantic Shores' proposed take estimates of the types and amounts of take for each species and stock are reasonable, with some minor adjustments, and is proposing to authorize the adjusted amount requested. NMFS notes the take estimates described herein for foundation installation are substantially conservative as the estimates do not reflect the implementation of clearance and shutdown zones for any marine mammal species or stock. In addition, our estimates for Project 2 assume pin pile buildouts where requested; however, Atlantic Shores may use monopiles instead in certain instances, which will result in generally lesser take.

Acoustic Thresholds

NMFS recommends the use of acoustic thresholds that identify the received level of underwater sound above which exposed marine mammals would be reasonably expected to be behaviorally harassed (Level B harassment) or to incur PTS of some degree (Level A harassment). A summary of all NMFS' thresholds can be found at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

Level B Harassment

Though significantly driven by received level, the onset of behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source or exposure context ( e.g., frequency, predictability, duty cycle, duration of the exposure, signal-to-noise ratio, distance to the source, ambient noise, and the receiving animal's hearing, motivation, experience, demography, behavior at time of exposure, life stage, depth) and can be difficult to predict ( e.g., Southall et al., 2007, 2021; Ellison et al., 2012). Based on what the available science indicates and the practical need to use a threshold based on a metric that is both predictable and measurable for most activities, NMFS typically uses a generalized acoustic threshold based on received level to estimate the onset of behavioral harassment.

NMFS generally predicts that marine mammals are likely to be behaviorally harassed in a manner considered to be Level B harassment when exposed to underwater anthropogenic noise above the received sound pressure levels (SPL_RMS) of 120 dB for continuous sources ( e.g., vibratory pile-driving, drilling) and above the received SPL_RMS 160 dB for non-explosive impulsive or intermittent sources ( e.g., impact pile driving, scientific sonar). Generally speaking, Level B harassment take estimates based on these behavioral harassment thresholds are expected to include any likely takes by TTS as, in most cases, the likelihood of TTS occurs at distances from the source less than those at which behavioral harassment is likely. TTS of a sufficient degree can manifest as behavioral harassment, as reduced hearing sensitivity and the potential reduced opportunities to detect important signals (conspecific communication, predators, prey) may result in changes in behavioral patterns that would not otherwise occur.

The proposed project's construction activities include the use of continuous ( e.g., vibratory pile driving) and impulsive or intermittent sources ( e.g., impact pile driving, some HRG acoustic sources); therefore, the 120 and 160 dB re 1 μPa (rms) thresholds are applicable to our analysis.

Level A Harassment

NMFS' Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; Technical Guidance) (NMFS, 2018) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). As dual metrics, NMFS considers onset of PTS (Level A harassment) to have occurred when either one of the two metrics is exceeded ( i.e., metric resulting in the largest isopleth). As described above, the proposed activities include the use of both impulsive and non-impulsive sources. NMFS' thresholds identifying the onset of PTS are provided in Table 6. The references, analysis, and methodology used in the development of the thresholds are described in NMFS' 2018 Technical Guidance, which may be accessed at www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

Below we describe the assumptions and methodologies used to estimate take, in consideration of acoustic thresholds and appropriate marine mammals density and occurrence information, for WTG, OSS, and Met Tower foundation installation, temporary cofferdam installation, and HRG surveys. Resulting distances to thresholds, densities used, activity-specific exposure estimates (as relevant to the analysis), and activity-specific take estimates can be found in each activity subsection below. At the end of this section, we present the amount of annual and 5-year take that Atlantic Shores requested, and NMFS proposes to authorize, from all activities combined.

Acoustic and Exposure Modeling

The predominant underwater noise associated with the construction of the project results from impact and vibratory pile driving. Atlantic Shores employed JASCO Applied Sciences (USA) Inc. (JASCO) to conduct acoustic modeling to better understand sound fields produced during these activities (Weirathmueller et al., 2022). The basic modeling approach is to characterize the sounds produced by the source, and determine how the sounds propagate within the surrounding water column. For impact pile driving, JASCO conducted sophisticated source and propagation modeling (as described below). For vibratory pile driving activities, JASCO applied in situ data to estimate source levels and applied more simple propagation modeling. To assess the potential for take from impact pile driving, JASCO also conducted animal movement modeling to estimate exposures; JASCO estimated species-specific exposure probability by considering the range- and depth-dependent sound fields in relation to animal movement in simulated representative construction scenarios. To assess the potential for take from vibratory pile driving, exposure modeling was not conducted; instead, a density-based estimation approach was used. More details on these acoustic source modeling, propagation modeling, and exposure modeling methods are described below.

JASCO's Pile Driving Source Model (PDSM), a physical model of pile vibration and near-field sound radiation (MacGillivray, 2014), was used in conjunction with the GRL, Inc Wave Equation Analysis of Pile Driving (GRLWEAP) 2010 wave equation model (Pile Dynamics, 2010) to predict representative source levels associated with impact pile driving activities (WTG, OSS, and Met Tower foundation installation). The PDSM physical model computes the underwater vibration and sound radiation of a pile by solving the theoretical equations of motion for axial and radial vibrations of a cylindrical shell. This model is used to estimate the energy distribution per frequency (source spectrum) at a close distance from the source (10 m). Piles are modeled as a vertical installation using a finite-difference structural model of pile vibration based on thin-shell theory. To model the sound emissions from the piles, the force of the pile driving hammers also had to be modeled. The force at the top of each monopile and jacket foundation pile was computed using the GRLWEAP 2010 wave equation model, which includes a large database of simulated hammers. The forcing functions from GRLWEAP were used as inputs to the finite difference model to compute the resulting pile vibrations (see Figures 8–10 in Appendix B of Atlantic Shores' ITA application for the computed forcing functions). The sound radiating from the pile itself was simulated using a vertical array of discrete point sources. These models account for several parameters that describe the operation—pile type, material, size, and length—the pile driving equipment, and approximate pile penetration depth. The model assumed direct contact between the representative hammers, helmets, and piles ( i.e., no cushioning material). For both jacket and monopile foundation models, the piles are assumed to be vertical and driven to a penetration depth of 70 m (230 ft) and 60 m (197 ft), respectively.

Atlantic Shores is required to employ noise abatement systems (NAS), also known as noise attenuation systems, during all foundation installation ( i.e., impact pile driving) activities to reduce the sound pressure levels that are transmitted through the water in an effort to reduce ranges to acoustic thresholds and minimize any acoustic impacts resulting from the activities. Atlantic Shores is required to use whatever technology is necessary to ensure that measured sound levels do not exceed the levels modeled for a 10-dB sound level reduction for foundation installation, which is likely to include a double big bubble curtain combined with another NAS ( e.g., hydro-sound damper, or an AdBm Helmholtz resonator), as well as the adjustment of operational protocols to minimize noise levels. Other systems that could be implemented include an evacuated sleeve system ( e.g., IHC-Noise Mitigation System (NMS)), or encapsulated bubble systems ( e.g., HydroSound Dampers (HSD)) to reduce sound levels. Hence, hypothetical broadband attenuation levels of 0 dB, 6 dB, 10 dB, and 15 dB were incorporated into the foundation source models to gauge effects on the ranges to thresholds given these levels of attenuation (Appendix B of the ITA application). Although four attenuation levels were evaluated, Atlantic Shores and NMFS anticipate that the noise attenuation system ultimately chosen will be capable of reliably reducing source levels by 10 dB; therefore, this assumption was carried forward in this analysis for monopile and jacket foundation pile driving installation. See the Proposed Mitigation section for more information regarding the justification for the 10-dB assumption.

In addition to considering noise abatement, the amount of sound generated during pile driving varies with the energy required to drive piles to a desired depth and depends on the sediment resistance encountered. Sediment types with greater resistance require hammers that deliver higher energy strikes and/or an increased number of strikes relative to installations in softer sediment. Maximum sound levels usually occur during the last stage of impact pile driving where the greatest resistance is encountered (Betke, 2008). Key modeling assumptions for the monopiles and pin piles are listed in Table 7 (additional modeling details and input parameters can be found in Table B–1 in Appendix B of Atlantic Shores' ITA application). Hammer energy schedules for monopiles (12-m and 15-m) and pin piles (5-m) are provided in Table 8, respectively. Decidecade spectral source levels for each pile type, hammer energy, and modeled location for summer sound speed profiles can be found in Appendix B of Atlantic Shores' ITA application (see Figures 11 to 13 in the application).

Within these assumptions, jacket foundations were assumed to be pre- and post-piled. Pre-piled means that the jacket structure is set on pre-installed piles while post-piling means that that jacket structure is placed on the seafloor and the piles are subsequently driven through guides located at the base of each jacket leg. Due to these installation approaches, the jacket structure itself radiates sound, which needs to be accounted for in the modeling. Because of this, JASCO estimated a larger broadband sound level for the piles (+2 dB) for the post-piling scenario.

After calculating source levels, Atlantic Shores used propagation models to estimate distances to NMFS' harassment thresholds. The propagation of sound through the environment can be modeled by predicting the acoustic propagation loss—a measure, in decibels, of the decrease in sound level between a source and a receiver some distance away. Geometric spreading of acoustic waves is the predominant way by which propagation loss occurs. Propagation loss also happens when the sound is absorbed and scattered by the seawater, and absorbed, scattered, and reflected at the water surface and within the seabed. Propagation loss depends on the acoustic properties of the ocean and seabed and its value changes with frequency. Acoustic propagation modeling for impact pile driving applied JASCO's Marine Operations Noise Model (MONM) and Full Wave Range Dependent Acoustic Model (FWRAM) that combine the outputs of the source model with the spatial and temporal environmental context ( e.g., location, oceanographic conditions, and seabed type) to estimate sound fields. The lower frequency bands were modeled using MONM–RAM, which is based on the parabolic equation method of acoustic propagation modeling. For higher frequencies, additional losses resulting from absorption were added to the transmission loss model. See Appendix B and D in Atlantic Shores' application (and supplemental memos) for more detailed descriptions of JASCO's propagation models.

Sounds produced by installation of the proposed monopiles and pin piles were modeled at two sites (L01 and L02) for the 12-m and 15-m diameter monopile foundations and for the 5-m pin piles for jacket foundations—L01 in the southern section of the Lease Area in 36.1 m (118.4 ft) of water depth and L02 in the northeastern section of the Lease Area in 28.1 m (92.2 ft) of water depth. Modeling locations are shown in Figure 2 of Appendix B in the ITA application. For temporary cofferdams, simpler propagation modeling using in-situ data was performed using information from Illingworth & Rodkin (2017), which measured the sound exposure level at 10 m (32.8 ft) distance from the pile for sheet piles using a vibratory hammer. JASCO used the source spectrum produced from this study (see Figure 2 in Appendix D, the revised cofferdam memo) to define the expected source characteristics during Atlantic Shores' cofferdam installation and removal activities. JASCO's model, MONM, was again used to predict the SEL and SPL fields at representative locations near the proposed cofferdam locations, considering the influences of bathymetry, seabed properties, water sound speed, and water attenuation. Sheet piles were represented as a point source at a depth of 2 m (6.56 ft).

Due to seasonal changes in the water column, sound propagation is likely to differ at different times of the year. The speed of sound in seawater depends on the temperature T (degree Celsius), salinity S (parts per thousand (ppt)), and depth D (m) and can be described using sound speed profiles. Oftentimes, a homogeneous or mixed layer of constant velocity is present in the first few meters. It corresponds to the mixing of surface water through surface agitation. There can also be other features, such as a surface channel, which corresponds to sound velocity increasing from the surface down. This channel is often due to a shallow isothermal layer appearing in winter conditions, but can also be caused by water that is very cold at the surface. In a negative sound gradient, the sound speed decreases with depth, which results in sound refracting downwards which may result in increased bottom losses with distance from the source. In a positive sound gradient, as is predominantly present in the winter season, sound speed increases with depth and the sound is, therefore, refracted upwards, which can aid in long distance sound propagation. Within the Project Area from July through September, the average temperature of the upper 10 m to 15 m of the water column is higher, resulting in an increased surface layer sound speed.

Acoustic propagation modeling for impact pile driving foundations was conducted using an average sound speed profile for a summer period given this would be when Atlantic Shores would conduct the majority, if not all of its foundation installation work. Vibratory pile driving for cofferdams used a mean summer (June–August) and mean winter (December–February), given the specifics described in the construction schedule. FWRAM computes pressure waveforms via Fourier synthesis of the modeled acoustic transfer function in closely spaced frequency bands. Examples of decidecade spectral levels for each foundation pile type, hammer energy, and modeled location, using average summer sound speed profile are provided in Weirathmueller et al. (2022). Resulting distances to NMFS' harassment thresholds for impact driving and vibratory driving cofferdams can be found in the WTG, OSS, and Met Tower Foundation Installation and Cable Landfall Activities subsections, respectively, below.

To estimate the probability of exposure of animals to sound above NMFS' harassment thresholds during impact pile driving for foundation installation, JASCO's Animal Simulation Model Including Noise Exposure (JASMINE) was used to integrate the sound fields generated from the source and propagation models described above with species-typical behavioral parameters ( e.g., dive patterns). Sound exposure models such as JASMINE use simulated animals (animats) to sample the predicted 3–D sound fields with movement rules derived from animal observations. Animats that exceed NMFS' acoustic thresholds are identified and the range for the exceedances determined. The output of the simulation is the exposure history for each animat within the simulation. An individual animat's sound exposure levels are summed over a specific duration (24 hours), to determine its total received acoustic energy (sound exposure level (SEL)) and maximum received PK and SPL. These received levels are then compared to the threshold criteria within each analysis period.

JASCO ran JASMINE simulations for 7 days, assuming piling every day. Separate simulations were run for each scenario ( e.g., pile diameter/number of piles per day/season combination). The combined history of all animats gives a probability density function of exposure during the project. The number of animals expected to exceed the regulatory thresholds per day is determined by scaling the number of predicted animat exposures by the species-specific density of animals in the area. The average number of exposures per day for the scenario in question was then multiplied by the number of days of pile driving planned for that scenario. In general, the number of days of pile driving is more influential in determining total exposures for Level B harassment than Level A harassment. However, the use of other conservative parameters ( e.g., assuming most pile driving occurs in highest density months) in the calculation ensure that, regardless, the estimated take numbers appropriately represent the maximum number of instances marine mammals are reasonably likely to be harassed by the activities.

By programming animats to behave like marine species that may be present near the Project Area, the sound fields are sampled in a manner similar to that expected for real animals. The parameters used for forecasting realistic behaviors ( e.g., diving, foraging, and surface times) were determined and interpreted from marine species studies ( e.g., tagging studies) where available, or reasonably extrapolated from related species (Weirathmueller et al., 2022).

For modeled animals that have received enough acoustic energy to exceed a given harassment threshold, the exposure range for each animal is defined as the closest point of approach (CPA) to the source made by that animal while it moved throughout the modeled sound field, accumulating received acoustic energy. The CPA for each of the species-specific animats during a simulation is recorded and then the CPA distance that accounts for 95 percent of the animats that exceed an acoustic impact threshold is determined. The ER₉₅% (95 percent exposure radial distance) is the horizontal distance that includes 95 percent of the CPAs of animats exceeding a given impact threshold. The ER₉₅% ranges are species-specific rather than categorized only by any functional hearing group, which allows for the incorporation of more species-specific biological parameters ( e.g., dive durations, swim speeds, etc.) for assessing the potential for PTS from impact pile driving.

Atlantic Shores also calculated acoustic ranges which represent the distance to harassment thresholds based on sound propagation through the environment independent of any receiver. As described above, applying animal movement and behavior within the modeled noise fields allows for a more realistic indication of the distances at which PTS acoustic thresholds are reached that considers the accumulation of sound over different durations. The use of acoustic ranges (R₉₅% ) to the Level A harassment SEL_cum metric thresholds to assess the potential for PTS is considered overly conservative as it does not account for animal movement and behavior and, therefore, assumes that animals are essentially stationary at that distance for the entire duration of the pile installation, a scenario that does not reflect realistic animal behavior. The acoustic ranges to the SEL_cum Level A harassment thresholds for impact pile driving can be found in Atlantic Shores' ITA application but will not be discussed further in this analysis. However, because NMFS' Level A harassment (PTS dB_peak) and Level B harassment (SPL) thresholds refer to instantaneous exposures, acoustic ranges are more relevant to the analysis. Also, because animat modeling was not conducted for vibratory pile driving, acoustic range is used to assess Level A harassment (dB SEL). Acoustic ranges to the Level A harassment (dB_peak), Level A harassment (dB SEL; vibratory pile driving only), and Level B harassment threshold for each activity are provided in the WTG, OSS, and Met Tower Foundation Installation subsection below. The differences between exposure ranges and acoustic ranges for Level B harassment are minimal given it is an instantaneous method.

Density and Occurrence

In this section we provide the information about marine mammal density, presence, and group dynamics that informed the take calculations for all activities. For foundation installation and temporary cofferdam installation and removal, JASCO performed the analysis, while Environmental Design & Research, Landscape Architecture, Engineering & Environmental Services, D.P.C. (EDR) assessed HRG surveys, on behalf of Atlantic Shores. In either case, the 2022 Duke University Marine Geospatial Ecology Laboratory Habitat-based Marine Mammal Density Models for the U.S. Atlantic ( i.e., the Duke University density models; Roberts et al., 2016; Roberts et al., 2023) were applied to estimate take from foundation installation, temporary cofferdam installation and removal, and HRG surveys (please see each activity subsection below for the resulting densities). The models estimate absolute density (individuals/100 km² ) by statistically correlating sightings reported on shipboard and aerial surveys with oceanographic conditions. For most marine mammal species, densities are provided on a monthly basis. Where monthly densities are not available ( e.g., pilot whales), annual densities are provided. Moreover, some species are represented as guilds ( e.g., seals (representing Phocidae spp. comprising harbor and gray seals) and pilot whales (representing short-finned and long-finned pilot whales)).

The Duke University density models delineate species' density into 5 x 5 km (3.1 x 3.1 mi) grid cells. Atlantic Shores calculated mean monthly densities for each species using grid cells within the Lease Area and a predetermined buffer around the Lease Area that represented the expected ensonified area to NMFS' harassment thresholds for each sound-producing activity. All 5 x 5 km grid cells in the models that fell partially or fully within the analysis polygon were considered in the calculations. Cells that fell entirely on land were not included, but cells that overlapped only partially with land were included.

For impact pile driving, the buffer from the edge of the Lease Area was chosen as it was based on the largest 10 dB-attenuated (from the bubble curtain/NAS) exposure range calculated based on installation of a 15-m monopile using a 4,400 kJ hammer (3.9 km (2.4); Table 9). For vibratory pile driving associated with temporary cofferdam installation and removal, Atlantic Shores applied the applicable buffer sizes at each of the landfall locations (7.546 km (4.7 mi) at the Atlantic site and 11.286 km (7 mi) at the Monmouth site) based on the R₉₅% value for the largest acoustic range to threshold (Table 10). For HRG surveys, Atlantic Shores mapped the density data within the boundary of each survey area using geographic information systems (GIS). No buffer was applied given the small distance to Level B harassment (<200 m) during surveys compared to the grid cell size in the Duke University density models (5 x 5 km; Table 11).

Densities were computed based on when the proposed activities were expected. For foundation installation, densities were accrued monthly, annually, and specifically for the May-December period that coincided with the proposed pile driving activities. For temporary cofferdams, maximum monthly densities were calculated based on the planned September to May construction period. For HRG surveys, the maximum average seasonal density value for each marine mammal species was calculated.

Here we note some exceptions, based on the availability of data. For the pilot whale guild ( i.e., long-finned and short-finned), monthly densities are unavailable so annual mean densities were used instead. Additionally, the models provide density for pilot whales as a guild that includes both species. To obtain density estimates for long-finned and short-finned pilot whales, the guild density was scaled by the relative stock sizes based on the best available abundance estimate from NOAA Fisheries SARs (NOAA Fisheries, 2021b). Similarly, gray and harbor seal densities were scaled by each of their relative abundances, as found in the NOAA Fisheries SARs (NOAA Fisheries, 2021b). These scaled and surrogate densities were carried forward to the exposure and take estimates. Please see the activity-specific subsections below for resulting densities.

The equation below, using pilot whales as an example, shows how abundance scaling is applied to compute densities for the pilot whale and seal guilds.

Dshort-finned = Dboth × (Nshort-finned/(Nshort-finned + Nlong-finned))

Where D represents density and N represents abundance.

For some species and activities, Atlantic Marine Assessment Program for Protected Species (AMAPPS) data from 2010–2019 shipboard distance sampling surveys (Palka et al., 2021) and observational data collected during previous site assessment surveys in the Project Area indicate that the density-based exposure estimates may be insufficient to account for the number of individuals of a species that may be encountered during the planned activities. This is particularly true for uncommon or rare species with very low densities in the models. Hence, consideration of other data is required to ensure the potential for take is adequately assessed.

Here we note the existence of two different stocks of bottlenose dolphins, the coastal and offshore stocks, near the Project Area. However, the best available science consists of only a combined, single bottlenose dolphin density model found in Roberts et al. (2023). To appropriately account for which stock may be taken during foundation installation, the 3.9 km buffer was split at the 20-m isobath. Any bottlenose dolphins found within the 20-m isobath to shore were allocated to the coastal stock. Any that were outside of the 20-m isobath more seaward were allocated to the offshore stock. Animat simulations were run for each stock separately with the same behavioral characteristics. Because of this, the exposure ranges are very similar between the two stocks as the only difference would be due to the different random seeding that was incorporated into the analysis. During cofferdam installation and removal, it was assumed that all dolphins near the Atlantic landfall site would consist of the coastal stock, which allowed for a density value of zero for the offshore stock. However, given the Atlantic landfall site did not exceed the 20-m isobath but the Monmouth site did, the area used to calculate the densities for bottlenose dolphins was split at the 20-m isobath. Because of this, any area <20 m deep and >20 m deep were used to calculate the exposures and takes for the coastal and offshore stocks, respectively. For HRG surveys, given that the northern migratory stock has more often been found in waters shallower than 20 m, the survey area was divided along the 20-m isobath break. Atlantic Shores estimated that 33 percent of the survey area fell from the 20-m isobath landward; therefore, 33 percent of the estimated take calculated for bottlenose dolphins was allocated to the coastal stock and the remaining was applied to the offshore stock.

Mean group sizes were used in the take estimation and were derived from NMFS' data upload to the Ocean Biodiversity Information System (OBIS) repository (OBIS, 2022), which is informed by information from the AMAPPS 2010–2019 aerial and shipboard surveys, North Atlantic right whale aerial surveys, and other surveys. The dataset was downloaded from OBIS and then filtered to include only observations from the Northwestern Atlantic region (extending from the Gulf of Maine to Cape Hatteras and the relevant shelf edge) with the institution owner code of “NMFS”. From there, the average group sizes were calculated as the mean value of the “individualCount” column for all sighting records for a species. Additional information was also incorporated based on Atlantic Shores' experience with site characterization surveys in this region through issued IHAs (87 FR 24103, April 22, 2022; 88 FR 38821, June 14, 2023). This yielded unique group sizes for long-finned pilot whales, Atlantic spotted dolphins, and Risso's dolphins that were used rather than the OBIS dataset.

Additional detail regarding the density and occurrence as well as the assumptions and methodology used to estimate take for specific activities is included in the activity-specific subsections below and in the February 2023 update memo. Average group sizes used in take estimates, where applicable, for all activities are provided in Table 12.

WTG, OSS, and Met Tower Foundation Installation

Here we describe the results from the acoustic, exposure, and take estimate methodologies outlined above for WTG, OSS, and Met Tower foundation installation activity that have the potential to result in harassment of marine mammals ( i.e., impact pile driving). We present exposure ranges to Level A harassment (SEL) thresholds from impact driving, acoustic ranges to Level A harassment (peak) and Level B harassment thresholds, densities, exposure estimates, and the amount of take requested and proposed to be authorized incidental to foundation installation following the aforementioned assumptions ( e.g., construction and hammer schedules). As described above, this proposed rule analyzes a modified Schedule 2 which accommodates a full monopile WTG build-out of Project 1 and Met Tower and a full jacket buildout for the WTGs in Project 2. Schedule 2 assumes foundation installation activities would occur over a 2 year period (May through December, annually).

As previously described, JASCO integrated the results from acoustic source and propagation modeling into an animal movement model to calculate exposure ranges for 16 marine mammal species (17 stocks) considered common in the Project Area. The resulting ranges represent the distances at which marine mammals may incur Level A harassment ( i.e., PTS).

As described in the Detailed Description of Specified Activities section, Atlantic Shores' preference is to install 15-m monopiles but Atlantic Shores may alternatively install 12-m monopiles. Hence, we have provided the modeled exposure and ranges for 12-m and 15-m monopiles below. We note that because the 15-m monopiles produce larger sound fields in general, in order to ensure a conservative analysis, this proposed rule assumes all take is consistent with that expected for the 15-m monopiles.

Similarly, as described in the Detailed Description of Specified Activities section, Atlantic Shores may install pre- or post-piled pin piles to construct the jacket foundations. We note that because post-piled pin piles produce larger sound fields than pre-piled piles, this proposed rule carries forward take specific to the post-piled pin piles. To more appropriately account for the larger radiated area produced around the jacket foundations as pin piles are driven, the broadband sound level estimated for the jacket piles was increased by 2 dB in all post-piling scenarios.

Table 13 provides the exposure ranges for impact pile driving of a 12-m monopile, 15-m monopile, and 5-m pin pile and (pre- and post-piled) jacket foundations, assuming 10 dB of sound attenuation to the PTS (SEL) thresholds.

We note here that between the two differently sized monopiles, all of the distances to the Level A harassment threshold are smaller for the 12-m, with exception for the harbor porpoise distances, which show minute differences between the 15-m (0.26 and 0.28) and the 12-m (0.39 and 0.32) for each of one or two piles installed per day, respectively (Table 13). This is because as the pile diameter increases from 12 to 15 meters, the frequency spectrum shifts. More of the energy increase occurs at the lower frequencies, which are largely filtered out by the high-frequency weighting function.

As described above, JASCO also calculated acoustic ranges which represent distances to NMFS' harassment isopleths independent of movement of a receiver. Presented below are the distances to the PTS (dB peak) threshold for impact pile driving and the Level B harassment (SPL) thresholds for all impact pile driving during WTG, OSS, and Met Tower foundation installation (Tables 14 and 15).

Next, the specific densities for each marine mammal species were incorporated. Initially, Atlantic Shores provided the densities used in the analysis in their ITA application. However, due to the June 2022 release of the updated Duke University density models, Atlantic Shores submitted a memo with the revised densities and the derived exposure and take estimates. These were the values NMFS carried forward into this proposed rule (refer back to Tables 9, 10, and 11).

To estimate take from foundation installation activities, Atlantic Shores assumed the buildout described for the modified Schedule 2 (see the PDE Refinement Memo), which entails that all WTGs and the Met Tower found within Project 1 would be built using 15-m monopiles and all WTGs in Project 2 would be built on jacket foundations using 5-m piles. All OSSs would be built on jacket foundations using 5-m pin piles. The full buildout of Atlantic Shores South (200 WTGs) assuming Schedule 2 is provided on Table 16. This represents the maximum amount of take that would occur incidentally to Atlantic Shores South as no more than 200 WTGs, 1 Met Tower, and 10 OSSs will be installed within the Lease Area. However, Atlantic Shores has requested NMFS issue two distinct LOAs for each of Project 1 and Project 2. Hence, there is a need to also estimate the maximum amount of annual take from each Project which, collectively, is greater given it is currently unknown exactly how many WTG and OSSs will be constructed in each Project. For this analysis, it was assumed that Project 1 may have a maximum of 105 WTGs (plus 6 WTG foundations installed as part of the Overlap Area for Project 1; n=111), 1 Met Tower, and 2 OSSs and Project 2 may have a maximum of 89 WTGs (plus 6 WTG foundations installed as part of the Overlap Area for Project 2; n=95) and 2 OSS. As described above, the number of days of pile driving per month is part of the exposure estimate calculation. Atlantic Shores assumes that 1 monopile could be installed per day and four pin piles could be installed per day.

Atlantic Shores assumes that construction would start in 2026 for foundation installation (Table 16). Modeling assumed that up to 106 monopile foundations (105 WTGs plus the Met Tower) would be installed during May through October in the area for Project 1 (2026) and up to 89 monopiles (WTGs) for Project 2 for May through December (in part of 2026 and in 2027). Additionally, up to 6 monopile foundations (WTGs) could be installed during November through December for either Project 1 or Project 2 (total of 112 WTG and Met Tower foundations for Project 1 or a total of 94 WTG foundations for Project 2). This also assumes the buildout of two large-sized OSSs each being installed on jacket foundations during June and August for each of Project 1 and for Project 2. Atlantic Shores expects that all foundation installation activities for Project 1 would occur during the first year of construction activities (2026) with parts of Project 2 starting in 2026 and completing in 2027.

Between these schedules, we note that Atlantic Shores has analyzed the construction of 205 permanent foundation structures, including up to 200 WTGs, one Met Tower, and 4 large-sized OSSs. The 6 WTGs in the overlap area are included in the maximum take calculation for each of Project 1 and Project 2. The Project 1 take calculations include the 6 WTGs in the overlap area during Year 1 to ensure sufficient take for Project 1 (if those positions are allocated to Project 1 during construction). If, however, those positions are allocated to Project 2, they are also included during Year 1 of foundation installation for Project 2 (to ensure sufficient take allocation to Project 2 during that year). However, the full buildout scenario, which describes the take for the Projects combined, only includes the 6 WTGs in the entire project once (to avoid double counting of the 6 WTGs).

As described previously, to estimate the amount of take that may occur incidental to the foundation installation, Atlantic Shores conducted exposure modeling to estimate the number of exposures that may occur from impact pile driving in a 24-hour period. Exposure estimates were then scaled to reflect the appropriate density estimates as described above. These scaled 24-hour exposure estimates were then multiplied by the number of days to produce the estimated take numbers for each year. Exposure estimates can be found within the LOA Updates Memo on NMFS' website.

As described above, exposure estimates were subsequently adjusted based on appropriate group sizes and PSO data (refer back to Table 12) to yield the requested take in Atlantic Shores' LOA Updates Memo. The amount of take Atlantic Shores requested similarly equates to the amount of take NMFS proposes to authorize (Tables 17 and 18).

Based on Tables 17 and 18 above, NMFS proposes to authorize the following numbers for the harassment of marine mammals incidental to foundation installation activities of WTGs, OSSs, and the Met Tower by Level A harassment and Level B harassment in Table 19. We note that Atlantic Shores did not request, nor is NMFS proposing to authorize, serious injury and/or mortality of marine mammals. Furthermore, no Level A harassment of North Atlantic right whales has been proposed for authorization due to enhanced mitigation measures that Atlantic Shores would be required to implement for this species.

Cable Landfall Activities

We previously described the acoustic modeling and static methodologies to estimate the take of marine mammals and have already identified that Atlantic Shores estimated take using propagation modeling which then used a static density-based approach. This information will not be reiterated here. Here, we present the results of acoustic modeling and take estimation processes, as previously described. More information can also be found in the ITA application and subsequent supplementary memos provided by the applicant.

Atlantic Shores proposes to install and remove up to four temporary cofferdams per Atlantic and Monmouth cable landfall location (eight cofferdams total) using a vibratory hammer. To calculate the acoustic ranges to PTS thresholds, it was assumed that up to 8 hours of vibratory pile driving would occur within any 24-hour period. The furthest ranges were noted where the sound propagated offshore from the New Jersey coastline into the continental shelf (see Figure 3 in the supplemental memo for Appendix D). Variation in acoustic ranges between the two sites is due to differing propagation loss properties. See Table 20 below for the ranges to the thresholds for both Level A harassment and Level B harassment.

Given the very small distances to the Level A harassment thresholds (0–540 m), which accounts for 8 hours of pile driving, installation and removal of temporary cofferdams is not expected to result in any Level A harassment of marine mammals. Atlantic Shores did not request, nor is NMFS proposing to authorize, any Level A harassment incidental to vibratory pile driving activities.

Using the acoustic ranges to the Level B harassment threshold, the ensonified area around each cable landfall construction site was determined for each of the two seasons ( i.e., summer and winter) using the following formula:

Ensonified Area = pi x r, ²

where r is the linear acoustic range distance from the source to the isopleth to the Level B harassment thresholds. Given the acoustic source is stationary, this formula assumes the distance to threshold would be the radius with the source in the center.

For vibratory pile driving associated with the sheet pile installation and removal necessary for cofferdams, it was assumed that the daily ensonified area was 104.33 km² (25,780.12 acres) at the Atlantic landfall site and 221.77 km² (54,799.57 acres) at the Monmouth landfall site. To estimate marine mammal densities around the nearshore landfall sites, the largest 95th percentile acoustic range to threshold (R₉₅% ; 7.546 km at the Atlantic site and 11.268 km at the Monmouth site) were used as density buffers. The maximum annual densities were calculated for each landfall location based on the average of the Duke University density model grid cells for each species and the period of time for when cofferdam activities may occur (September to May). Any grids that overlapped partially or completed were included. Grid cells that fell entirely on land were not included in the analysis, but due to the nearshore proximity of the cofferdams, grid cells that overlapped partially with land and water were included in the analysis. For two species guilds ( i.e., pinnipeds and pilot whale spp.), minor adjustments were necessary as the Roberts et al. (2023) data did not separate these by species. In these two cases, the densities were scaled by the relative abundance of each species, as described in the final 2022 SARs (Hayes et al., 2023).

Annual maximum marine mammal exposures were calculated assuming that cofferdam activities would only occur during the activity window of September through May. The density value for each species represented the highest density month for each specific species within this window, so as to not underestimate any potential take when the activity would occur. The exposures were calculated using the following static formula:

Exposures = area ensonified × (days) × density,

Where the area ensonified is equal to p × r ² , wherein r is equal to the Level B harassment isopleth distance, days constituted the total number of days needed for cofferdam activities (n=28), and density were incorporated as species-specific during the activity window.

The exposure estimates were calculated assuming 6 days of installation and 6 days of removal at the Atlantic City landfall location (n=12), and 8 days of installation and 8 days of removal at the Monmouth landfall location (n=28), equating to 28 days in total. In their adequate and complete ITA application, Atlantic Shores initially proposed 16 days total for the Atlantic City landfall location (8 days of installation and 8 days of removal). However, given the shallower waters at this location, they believe that it would be possible to install and remove the temporary cofferdams more quickly than initially modeled, thus reducing the total number of days at this location (n=12). Where applicable, calculated exposure estimates were then adjusted up for average group sizes, per Table 12, to yield the proposed take numbers. The estimated take and maximum amount of take proposed for authorization during temporary cofferdam installation and removal during the proposed Project is in Table 21. No take by Level A harassment is expected, nor has it been requested by Atlantic Shores or proposed for authorization by NMFS.

HRG Surveys

Atlantic Shores' proposed HRG survey activities include the use of impulsive ( i.e., sparkers) and non-impulsive sources ( i.e., CHIRPs) that have the potential to harass marine mammals. The list of all equipment proposed is in Table 2 (see Detailed Description of Specified Activities).

Authorized takes would be by Level B harassment only in the form of disruption of behavioral patterns for individual marine mammals resulting from exposure to noise from certain HRG acoustic sources. Specific to HRG surveys, in order to better consider the narrower and directional beams of the sources, NMFS has developed a calculation tool, available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance, for determining the distances at which sound pressure level (SPL_rms) generated from HRG surveys reach the 160 dB threshold. The equations in the tool consider water depth, frequency-dependent absorption and some directionality to refine estimated ensonified zones. Atlantic Shores used NMFS' methodology with additional modifications to incorporate a seawater absorption formula and account for energy emitted outside of the primary beam of the source. For sources operating with different beamwidths, the beamwidth associated with operational characteristics reported in Crocker and Fratantonio (2016) were used.

The isopleth distances corresponding to the Level B harassment threshold for each type of HRG equipment with the potential to result in harassment of marine mammals were calculated per NOAA Fisheries' Interim Recommendation for Sound Source Level and Propagation Analysis for High Resolution Geophysical Sources. The distances to the Level B harassment isopleth are presented in Table 22. Please refer to Appendix C for a full description of the methodology and formulas used to calculate distances to the Level B harassment threshold.

The survey activities that have the potential to result in Level B harassment (160 dB SPL) include the noise produced by sparkers and CHIRPS. Of these, the Applied Acoustics Dura-Spark 240 results in the greatest calculated distance to the Level B harassment criteria at 141 m (463 ft).

The total area ensonified was estimated by considering the distance of the daily vessel track line (determined using the estimated average speed of the vessel and the 24-hour operational period within each of the corresponding survey segments) and the longest horizontal distance to the relevant acoustic threshold from an HRG sound source (full formula in Section 6 of the ITA application and in the Revised HRG Memo on NMFS' website). Using the larger distance of 141 m to the 160 dB_RMS90% re 1 μPa Level B harassment isopleth (Table 22), the estimated daily vessel track of approximately 55 km (34.2 mi) per vessel for 24-hour operations, inclusive of an additional circular area to account for radial distance at the start and end of a 24-hour cycle, estimates of the total area ensonified to the Level B harassment threshold per day of HRG surveys were calculated (Table 22).

Exposure calculations assumed that there would be 60 days of HRG surveying per year over each of the 5 years. As described in the ITA application, density data were mapped within the boundary of the Project Area using geographic information systems. These data were updated based on the revised data from the Duke University density models. Because the exact dates of HRG surveys are unknown, the maximum average seasonal density values for each marine mammal species was used and carried forward in the take calculations (Table 23).

The calculated exposure estimates based on the exposure modeling methodology described above were compared with the best available information on marine mammal group sizes. Group sizes used for HRG take estimates were the same as those used for impact pile driving take estimation (refer back to Table 11). Atlantic Shores also used data collected by PSOs on survey vessels operating during HRG surveys in their 2020 season in the relevant Project Area. It was determined that the calculated number of potential takes by Level B harassment based on the exposure modeling methodology above may be underestimates for some species and therefore warranted adjustment using group size estimates and PSO data to ensure conservatism in the take numbers proposed for authorization. Despite the relatively small modeled Level B harassment zone (141 m) for HRG survey activities, it was determined that adjustments to the requested numbers of take by Level B harassment for some dolphin species was warranted (see below).

For certain species for which the density-based methodology described above may result in potential underestimates of take and Atlantic Shores' PSO sightings data were relatively low, adjustments to the exposure estimates were made based on the best available information on marine mammal group sizes to ensure conservatism. For species with densities too low in the region to provide meaningful modeled exposure estimates, the take request is based on the average group size (Table 12). Other adjustments were made based on information previously presented in previous IHAs issued to Atlantic Shores. These include an estimate of 1.55 individuals of common dolphins per day multiplied by the number of survey days annually ( i.e., 60 days), which is in alignment with what was done in 87 FR 24103 (April 22, 2022) based on previous daily observations of common dolphins. Additionally, requested take estimates for long-finned pilot whales, Atlantic spotted dolphins, and Risso's dolphins were also adjusted based on typical group sizes ( i.e., 20, 100, and 30 annual takes, respectively), based on take numbers from 2020, 2021, and 2022 IHAs issued to Atlantic Shores (see https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable#expired-authorizations ). Lastly, adjustments were made for short-finned pilot whales based on group size data reported by the OBIS data repository (OBIS, 2022). The average group size used was 6 individuals for short-finned pilot whales.

The maximum seasonal density used for the HRG survey analysis are shown in Table 11 in the Density and Occurrence section. The calculated take and the take proposed for authorization (via Level B harassment only) is found in Table 23 below.

Total Take Across All Activities

The amount of Level A harassment and Level B harassment NMFS proposes to authorize incidental to all project activities combined ( i.e., impact pile driving to install WTG, OSS, and Met tower foundations; vibratory pile driving to install and subsequently remove temporary cofferdams, and HRG surveys) are shown below. The annual amount of take that is expected to occur in each year based on Atlantic Shores' current schedules is provided in Table 24. The Year 1 take estimates include temporary cofferdam installation and HRG surveys. Year 2 includes foundation installation, temporary cofferdam installation, and HRG surveys. Year 3 includes take for foundation installation and HRG surveys. Year 4 and Year 5 each include HRG surveys. However, NMFS recognizes that schedules may shift due to a number of planning and logistical constraints such that take may be redistributed throughout the 5 years. However, the 5-year total amount of take for each species, shown in Table 25, and the maximum amount of take in any 1 year (Table 26) may not be exceeded.

The amount of take that Atlantic Shores requested, and NMFS proposes to authorize, is substantially conservative. For the species for which modeling was conducted, the take estimates are conservative for a number of reasons. The amount of take proposed to be authorized assumes the worst case scenario with respect to project design and schedules. As described in the Detailed Description of Specified Activities section and the applicant's PDE Refinement memo, Atlantic Shores may use suction-buckets or gravity-based structures to install the foundations for the Met Tower, and may use suction-buckets for each of the OSSs rather than monopiles or jacket foundations (depending on the size OSS used). Should Atlantic Shores decide to use these different foundations, take of marine mammals would not occur as noise levels would not be elevated to the degree there is a potential for take ( i.e., no pile driving is involved with installing suction buckets). All calculated take incorporated the maximum average densities for any given species in any given season. The amount of proposed Level A harassment does not fully account for the likelihood that marine mammals would avoid a stimulus when possible before the individual accumulates enough acoustic energy to potentially cause auditory injury, or the effectiveness of the proposed monitoring and mitigation measures (with the exception of North Atlantic right whales given the enhanced mitigation measures proposed for this species).

To inform both the negligible impact analysis and the small numbers determination, NMFS assesses the maximum number of takes of marine mammals that could occur within any given year. In this calculation, the maximum estimated number of Level A harassment takes in any 1 year is summed with the maximum estimated number of Level B harassment takes in any 1 year for each species to yield the highest number of estimated take that could occur in any year (Table 26). Table 26 also depicts the number of takes proposed relative to the abundance of each stock. The takes enumerated here represent daily instances of take, not necessarily individual marine mammals taken. One take represents a day (24-hour period) in which an animal was exposed to noise above the associated harassment threshold at least once. Some takes represent a brief exposure above a threshold, while in some cases takes could represent a longer, or repeated, exposure of one individual animal above a threshold within a 24-hour period. Whether or not every take assigned to a species represents a different individual depends on the daily and seasonal movement patterns of the species in the area. For example, activity areas with continuous activities (all or nearly every day) overlapping known feeding areas (where animals are known to remain for days or weeks on end) or areas where species with small home ranges live ( e.g., some pinnipeds) are more likely to result in repeated takes to some individuals. Alternatively, activities far out in the deep ocean or takes to nomadic species where individuals move over the population's range without spatial or temporal consistency represent circumstances where repeat takes of the same individuals are less likely. In other words, for example, 100 takes could represent 100 individuals each taken on 1 day within the year, or it could represent 5 individuals each taken on 20 days within the year, or some other combination depending on the activity, whether there are biologically important areas in the Project Area, and the daily and seasonal movement patterns of the species of marine mammals exposed. Wherever there is information to better contextualize the enumerated takes for a given species is available, it is discussed in the Negligible Impact Analysis and Determination and/or Small Numbers sections, as appropriate.

Proposed Mitigation

In order to promulgate a rulemaking under section 101(a)(5)(A) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to the activity, and other means of effecting the least practicable adverse impact on the species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stock for taking for certain subsistence uses (latter not applicable for this action). NMFS' regulations require applicants for incidental take authorizations to include information about the availability and feasibility (economic and technological) of equipment, methods, and manner of conducting the activity or other means of effecting the least practicable adverse impact upon the affected species or stocks and their habitat (50 CFR 216.104(a)(11)).

In evaluating how mitigation may or may not be appropriate to ensure the least practicable adverse impact on species or stocks and their habitat, as well as subsistence uses where applicable, we carefully consider two primary factors:

(1) The manner in which, and the degree to which, the successful implementation of the measure(s) is expected to reduce impacts to marine mammals, marine mammal species or stocks, and their habitat. This considers the nature of the potential adverse impact being mitigated (likelihood, scope, range). It further considers the likelihood that the measure will be effective if implemented (probability of accomplishing the mitigating result if implemented as planned), the likelihood of effective implementation (probability implemented as planned); and,

(2) The practicability of the measures for applicant implementation, which may consider such things as cost, impact on operations, and, in the case of a military readiness activity, personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity.

The mitigation strategies described below are consistent with those required and successfully implemented under previous incidental take authorizations issued in association with in-water construction activities ( e.g., soft-start, establishing shutdown zones). Additional measures have also been incorporated to account for the fact that the proposed construction activities would occur offshore. Modeling was performed to estimate harassment zones, which were used to inform mitigation measures for the Project's activities to minimize Level A harassment and Level B harassment to the extent practicable, while providing estimates of the areas within which Level B harassment might occur.

Generally speaking, the mitigation measures considered and proposed to be required here fall into three categories: temporal (seasonal and daily) work restrictions, real-time measures (shutdown, clearance, and vessel strike avoidance), and noise attenuation/reduction measures. Seasonal work restrictions are designed to avoid or minimize operations when marine mammals are concentrated or engaged in behaviors that make them more susceptible or make impacts more likely, in order to reduce both the number and severity of potential takes, and are effective in reducing both chronic (longer-term) and acute effects. Real-time measures, such as implementation of shutdown and clearance zones, as well as vessel strike avoidance measures, are intended to reduce the probability or severity of harassment by taking steps in real time once a higher-risk scenario is identified ( e.g., once animals are detected within an impact zone). Noise attenuation measures, such as bubble curtains, are intended to reduce the noise at the source, which reduces both acute impacts, as well as the contribution to aggregate and cumulative noise that may result in longer-term chronic impacts.

Below, we briefly describe the required training, coordination, and vessel strike avoidance measures that apply to all activity types, and then in the following subsections we describe the measures that apply specifically to foundation installation, nearshore installation and removal activities for cable laying, and HRG surveys. Details on specific requirements can be found in Part 217—Regulations Governing The Taking And Importing Of Marine Mammals at the end of this proposed rulemaking.

Training and Coordination

NMFS requires all Atlantic Shores' employees and contractors conducting activities on the water, including, but not limited to, all vessel captains and crew, to be trained in marine mammal detection and identification, communication protocols, and all required measures to minimize impacts on marine mammals and support Atlantic Shores' compliance with the LOA, if issued. Additionally, all relevant personnel and the marine mammal species monitoring team(s) are required to participate in joint, onboard briefings prior to the beginning of project activities. The briefing must be repeated whenever new relevant personnel ( e.g., new PSOs, construction contractors, relevant crew) join the project before work commences. During this training, Atlantic Shores is required to instruct all project personnel regarding the authority of the marine mammal monitoring team(s). For example, the HRG acoustic equipment operator, pile driving personnel, etc., are required to immediately comply with any call for a delay or shut down by the Lead PSO. Any disagreement between the Lead PSO and the project personnel must only be discussed after delay or shutdown has occurred. In particular, all captains and vessel crew must be trained in marine mammal detection and vessel strike avoidance measures to ensure marine mammals are not struck by any project or project-related vessel.

Prior to the start of in-water construction activities, vessel operators and crews would receive training about marine mammals and other protected species known or with the potential to occur in the Project Area, making observations in all weather conditions, and vessel strike avoidance measures. In addition, training would include information and resources available regarding applicable Federal laws and regulations for protected species. Atlantic Shores will provide documentation of training to NMFS.

North Atlantic Right Whale Awareness Monitoring

Atlantic Shores would be required to use available sources of information on North Atlantic right whale presence, including daily monitoring of the Right Whale Sightings Advisory System, monitoring of U.S. Coast Guard very high frequency (VHF) Channel 16 throughout each day to receive notifications of any sightings, and information associated with any regulatory management actions ( e.g., establishment of a zone identifying the need to reduce vessel speeds). Maintaining daily awareness and coordination affords increased protection of North Atlantic right whales by understanding North Atlantic right whale presence in the area through ongoing visual and passive acoustic monitoring efforts and opportunities (outside of Atlantic Shores' efforts), and allows for planning of construction activities, when practicable, to minimize potential impacts on North Atlantic right whales.

Vessel Strike Avoidance Measures

This proposed rule contains numerous vessel strike avoidance measures that reduce the risk that a vessel and marine mammal could collide. While the likelihood of a vessel strike is generally low, they are one of the most common ways that marine mammals are seriously injured or killed by human activities. Therefore, enhanced mitigation and monitoring measures are required to avoid vessel strikes, to the extent practicable. While many of these measures are proactive, intending to avoid the heavy use of vessels during times when marine mammals of particular concern may be in the area, several are reactive and occur when a project personnel sights a marine mammal. The mitigation requirements we propose are described generally here and in detail in the regulation text at the end of this proposed rule (see 50 CFR 217.264(b)). Atlantic Shores would be required to comply with these measures except under circumstances when doing so would create an imminent and serious threat to a person or vessel or to the extent that a vessel is unable to maneuver and, because of the inability to maneuver, the vessel cannot comply.

While underway, Atlantic Shores' personnel would be required to monitor for and maintain a minimum separation distance from marine mammals and operate vessels in a manner that reduces the potential for vessel strike. Regardless of the vessel's size, all vessel operators, crews, and dedicated visual observers ( i.e., PSO or trained crew member) must maintain a vigilant watch for all marine mammals and slow down, stop their vessel, or alter course (as appropriate) to avoid striking any marine mammal. The dedicated visual observer, equipped with suitable monitoring technology ( e.g., binoculars, night vision devices), must be located at an appropriate vantage point for ensuring vessels are maintaining required vessel separation distances from marine mammals ( e.g., 500 m from North Atlantic right whales).

All project vessels, regardless of size, must maintain the following minimum separation zones: 500 m from North Atlantic right whales; a 100 m zone from sperm whales and non-North Atlantic right whale baleen whales; and 50 m from all delphinid cetaceans and pinnipeds (an exception is made for those species that approach the vessel ( i.e., bow-riding dolphins)). If any of these species are sighted within their respective minimum separation zone, the underway vessel must shift its engine to neutral and the engines must not be engaged until the animal(s) have been observed to be outside of the vessel's path and beyond the respective minimum separation zone. If a North Atlantic right whale is observed at any distance by any project personnel or acoustically detected, project vessels must reduce speeds to 10 kn. Additionally, in the event that any project-related vessel, regardless of size, observes any large whale (other than a North Atlantic right whale) within 500 m of an underway vessel, the vessel is required to immediately reduce speeds to 10 kn or less. The 10 kn speed restriction will remain in effect as outlined in 50 CFR 217.264(b).

All of the project-related vessels would be required to comply with existing NMFS vessel speed restrictions for North Atlantic right whales and the measures within this rulemaking for operating vessels around North Atlantic right whales and other marine mammals. When NMFS vessel speed restrictions are not in effect and a vessel is traveling at greater than 10 kn, in addition to the required dedicated visual observer, Atlantic Shores would be required to monitor the crew transfer vessel transit corridor (the path crew transfer vessels take form port to any work area) in real-time with PAM prior to and during transits. To maintain awareness of North Atlantic right whale presence, vessel operators, crew members, and the marine mammal monitoring team will monitor U.S. Coast Guard VHF Channel 16, WhaleAlert, the Right Whale Sighting Advisory System (RWSAS), and the PAM system. Any marine mammal observed by project personnel must be immediately communicated to any on-duty PSOs, PAM operator(s), and all vessel captains. Any North Atlantic right whale or large whale observation or acoustic detection by PSOs or PAM operators must be conveyed to all vessel captains. All vessels would be equipped with an AIS and Atlantic Shores must report all Maritime Mobile Service Identify (MMSI) numbers to NMFS Office of Protected Resources prior to initiating in-water activities. Atlantic Shores will submit a NMFS-approved North Atlantic Right Whale Vessel Strike Avoidance Plan at least 90 days prior to commencement of vessel use.

Atlantic Shores' compliance with these proposed measures would reduce the likelihood of vessel strike to the extent practicable. These measures increase awareness of marine mammals in the vicinity of project vessels and require project vessels to reduce speed when marine mammals are detected (by PSOs, PAM, and/or through another source, e.g., RWSAS) and maintain separation distances when marine mammals are encountered. While visual monitoring is useful, reducing vessel speed is one of the most effective, feasible options available to reduce the likelihood of and effects from a vessel strike. Numerous studies have indicated that slowing the speed of vessels reduces the risk of lethal vessel collisions, particularly in areas where right whales are abundant and vessel traffic is common and otherwise traveling at high speeds (Vanderlaan and Taggart, 2007; Conn and Silber, 2013; Van der Hoop et al., 2014; Martin et al., 2015; Crum et al., 2019).

Seasonal and Daily Restrictions

Temporal restrictions in places where marine mammals are concentrated, engaged in biologically important behaviors, and/or present in sensitive life stages are effective measures for reducing the magnitude and severity of human impacts. The temporal restrictions required here are built around North Atlantic right whale protection. Based upon the best scientific information available (Roberts et al., 2023), the highest densities of North Atlantic right whales in the specified geographic region are expected during the months of January through April, with an increase in density starting in December. However, North Atlantic right whales may be present in the specified geographic region throughout the year.

NMFS is proposing to require seasonal work restrictions to minimize risk of noise exposure to the North Atlantic right whales incidental to certain specified activities to the extent practicable. These seasonal work restrictions are expected to greatly reduce the number of takes of North Atlantic right whales. These seasonal restrictions also afford protection to other marine mammals that are known to use the Project Area with greater frequency during winter months, including other baleen whales.

As described previously, no impact pile driving activities may occur January 1 through April 30. In addition, NMFS is proposing to require that Atlantic Shores install the foundations as quickly as possible and avoid pile driving in December to the maximum extent practicable; however, pile driving may occur in December if it is unavoidable upon approval from NMFS. Atlantic Shores has proposed to construct the cofferdams in 2025 and 2026 of the effective period of the regulations and LOA. However, NMFS is not requiring any seasonal restrictions due to the relatively short duration of work and low impacts to marine mammals. Although North Atlantic right whales do migrate in coastal waters, they do not typically migrate very close to shore off of New Jersey and/or within New Jersey bays where work would be occurring. Given the distance to the Level B harassment isopleth is conservatively modeled at approximately 11 km (36,089.2 ft), we expect that exposure to vibratory pile driving during cofferdam installation would be unlikely, and that if exposures occur, they will occur at levels consistent with only the Level B harassment threshold, and for only short durations given that large whales, if present, would likely be moving through the area in migration. NMFS is not proposing any seasonal restrictions to HRG surveys; however, Atlantic Shores would only perform a specific amount of 24-hour survey days within the proposed effective period of these regulations.

NMFS is also requiring temporal restrictions for some activities. Within any 24-hour period, Atlantic Shores would be limited to installing up to 2 monopile foundations or 4 pin piles. Atlantic Shores has requested to initiate pile driving during nighttime when detection of marine mammals is visually challenging. To date, Atlantic Shores has not submitted a plan containing the information necessary, including evidence, that their proposed systems are capable of detecting marine mammals, particularly large whales, at distances necessary to ensure mitigation measures are effective and, in general, the scientific literature on these technologies demonstrate there is a high degree of uncertainty in reliably detecting marine mammals at distances necessary for this project. Therefore, NMFS is not proposing, at this time, to allow Atlantic Shores to initiate pile driving later than 1.5 hours after civil sunset or 1 hour before civil sunrise. We are, however, proposing to encourage and allow Atlantic Shores the opportunity to further investigate and test advanced technology detection systems to support their request. NMFS is proposing to condition the LOA such that nighttime pile driving would only be allowed if Atlantic Shores submits an Alternative Monitoring Plan to NMFS for approval that proves the efficacy of their night vision devices ( e.g., mounted thermal/infrared (IR) camera systems, hand-held or wearable night vision devices (NVDs), IR spotlights) in detecting protected marine mammals. If the plan does not include a full description of the proposed technology, monitoring methodology, and data supporting that marine mammals can reliably and effectively be detected within the clearance and shutdown zones for monopiles and pin piles before and during impact pile driving, nighttime pile driving (unless a pile was initiated 1.5 hours prior to civil sunset) will not be allowed. The Plan should identify the efficacy of the technology at detecting marine mammals in the clearance and shutdowns under all the various conditions anticipated during construction, including varying weather conditions, sea states, and in consideration of the use of artificial lighting. Any and all vibratory pile driving associated with cofferdams installation and removal would only be able to occur during daylight hours. Lastly, given the very small Level B harassment zone associated with HRG survey activities and no anticipated or authorized Level A harassment, NMFS is not proposing any daily restrictions for HRG surveys.

More information on activity-specific seasonal and daily restrictions can be found in the regulatory text at the end of this proposed rulemaking.

Noise Abatement Systems

Atlantic Shores would be required to employ noise abatement systems (NAS), also known as noise attenuation systems, during all foundation installation ( i.e., impact pile driving) activities to reduce the sound pressure levels that are transmitted through the water in an effort to reduce acoustic ranges to the Level A harassment and Level B harassment acoustic thresholds and minimize, to the extent practicable, any acoustic impacts resulting from these activities. Atlantic Shores would be required to use at least two NAS to ensure that measured sound levels do not exceed the levels modeled for a 10-dB sound level reduction for foundation installation, which is likely to include a double big bubble curtain combined with another NAS (other available NAS technologies are the hydro-sound damper, or an AdBm Helmholz resonator), as well as the adjustment of operational protocols to minimize noise levels. A single bubble curtain, alone or in combination with another NAS device, may not be used for pile driving as received SFV data reveals this approach is unlikely to attenuate sound sufficiently to be consistent with the modeling underlying our take analysis here, which incorporates expected ranges to the Level A and Level B harassment isopleths assuming 10-dB of attenuation and appropriate NAS use. Should the research and development phase of newer systems demonstrate effectiveness, as part of adaptive management, Atlantic Shores may submit data on the effectiveness of these systems and request approval from NMFS to use them during foundation installation activities.

Two categories of NAS exist: primary and secondary. A primary NAS would be used to reduce the level of noise produced by foundation installation activities at the source, typically through adjustments on to the equipment ( e.g., hammer strike parameters). Primary NAS are still evolving and will be considered for use during mitigation efforts when the NAS has been demonstrated as effective in commercial projects. However, as primary NAS are not fully effective at eliminating noise, a secondary NAS would be employed. The secondary NAS is a device or group of devices that would reduce noise as it was transmitted through the water away from the pile, typically through a physical barrier that would reflect or absorb sound waves and, therefore, reduce the distance the higher energy sound propagates through the water column. Together, these systems must reduce noise levels to those not exceeding modeled ranges to Level A harassment and Level B harassment isopleths corresponding to those modeled assuming 10-dB sound attenuation, pending results of SFV (see Sound Field Verification section below and Part 217—Regulations Governing The Taking And Importing Of Marine Mammals).

Noise abatement systems, such as bubble curtains, are used to decrease the sound levels radiated from a source. Bubbles create a local impedance change that acts as a barrier to sound transmission. The size of the bubbles determines their effective frequency band, with larger bubbles needed for lower frequencies. There are a variety of bubble curtain systems, confined or unconfined bubbles, and some with encapsulated bubbles or panels. Attenuation levels also vary by type of system, frequency band, and location. Small bubble curtains have been measured to reduce sound levels but effective attenuation is highly dependent on depth of water, current, and configuration and operation of the curtain (Austin et al., 2016; Koschinski and Lüdemann, 2013). Bubble curtains vary in terms of the sizes of the bubbles and those with larger bubbles tend to perform a bit better and more reliably, particularly when deployed with two separate rings (Bellmann, 2014; Koschinski and Lüdemann, 2013; Nehls et al., 2016). Encapsulated bubble systems ( i.e., Hydro Sound Dampers (HSDs)), can be effective within their targeted frequency ranges ( e.g., 100–800 Hz), and when used in conjunction with a bubble curtain appear to create the greatest attenuation. The literature presents a wide array of observed attenuation results for bubble curtains. The variability in attenuation levels is the result of variation in design as well as differences in site conditions and difficulty in properly installing and operating in-water attenuation devices.

The literature presents a wide array of observed attenuation results for bubble curtains. The variability in attenuation levels is the result of variation in design as well as differences in site conditions, installation, and operation. For example, Dähne et al. (2017) found that single bubble curtains that reduce sound levels by 7 to 10 dB reduced the overall sound level by approximately 12 dB when combined as a double bubble curtain for 6-m steel monopiles in the North Sea. During installation of monopiles (consisting of approximately 8-m in diameter) for more than 150 WTGs in comparable water depths (>25 m) and conditions in Europe indicate that attenuation of 10 dB is readily achieved (Bellmann, 2019; Bellmann et al., 2020) using single big bubble curtains (BBCs) for noise attenuation. When a double big bubble curtain is used (noting a single bubble curtain is not allowed), Atlantic Shores would be required to maintain numerous operational performance standards. These standards are defined in the regulatory text at the end of this proposed rulemaking and include, but are not limited to: construction contractors must train personnel in the proposed balancing of airflow to the bubble ring and Atlantic Shores would be required to submit a performance test and maintenance report to NMFS within 72 hours following the performance test. Corrections to the attenuation device to meet regulatory requirements must occur prior to use during foundation installation activities. In addition, a full maintenance check ( e.g., manually clearing holes) must occur prior to each pile being installed. If Atlantic Shores uses a noise mitigation device in addition to a double big bubble curtain, similar quality control measures are required.

Atlantic Shores would be required to submit an SFV plan to NMFS for approval at least 180 days prior to installing foundations. They would also be required to submit interim and final SFV data results to NMFS and make corrections to the noise attenuation systems in the case that any SFV measurements demonstrate noise levels are above those modeled assuming 10 dB. These frequent and immediate reports would allow NMFS to better understand the sound fields to which marine mammals are being exposed and require immediate corrective action should they be misaligned with anticipated noise levels within our analysis.

Noise abatement devices are not required during HRG surveys and cofferdam (sheet pile) installation/removal. Regarding cofferdam sheet pile installation and removal, NAS is not practicable to implement due to the physical nature of linear sheet piles, and is of low risk for impacts to marine mammals due to the short work duration and lower noise levels produced during the activities. Regarding HRG surveys, NAS cannot practicably be employed around a moving survey ship, but Atlantic Shores would be required to make efforts to minimize source levels by using the lowest energy settings on equipment that has the potential to result in harassment of marine mammals ( e.g., sparkers, boomers) and turn off equipment when not actively surveying. Overall, minimizing the amount and duration of noise in the ocean from any of the project's activities through use of all means necessary ( e.g., noise abatement, turning off power) will effect the least practicable adverse impact on marine mammals.

Clearance and Shutdown Zones

NMFS is proposing to require the establishment of both clearance and shutdown zones during project activities that have the potential to result in harassment of marine mammals. The purpose of “clearance” of a particular zone is to minimize potential instances of auditory injury and more severe behavioral disturbances by delaying the commencement of an activity if marine mammals are near the activity. The purpose of a shutdown is to prevent a specific acute impact, such as auditory injury or severe behavioral disturbance of sensitive species, by halting the activity.

All relevant clearance and shutdown zones during project activities would be monitored by NMFS-approved PSOs and/or PAM operators (as described in the regulatory text at the end of this proposed rulemaking). At least one PAM operator must review data from at least 24 hours prior to foundation installation and actively monitor hydrophones for 60 minutes prior to commencement of these activities. Any sighting or acoustic detection of a North Atlantic right whale triggers a delay to commencing pile driving and shutdown.

Prior to the start of certain specified activities mammals (foundation installation, cofferdam install and removal, and HRG surveys), Atlantic Shores would be required to ensure designated areas ( i.e., clearance zones, Tables 27, 28, and 29) are clear of marine mammals prior to commencing activities to minimize the potential for and degree of harassment. For foundation installation, PSOs must visually monitor clearance zones for marine mammals for a minimum of 60 minutes, where the zone must be confirmed free of marine mammals at least 30 minutes directly prior to commencing these activities. Clearance zones represent the largest Level A harassment zone for each species group, plus 20 percent of a minimum of 100 m (whichever is greater). For foundation installation, the minimum visibility zone would extend 1,900 m (6,233.6 ft) from the pile (Table 27). This value corresponds to the modeled maximum ER₉₅% distances to the Level A harassment threshold for low-frequency cetaceans, assuming 10 dB of attenuation.

For cofferdam vibratory pile driving and HRG surveys, monitoring must be conducted for 30 minutes prior to initiating activities and the clearance zones (Tables 28 and 29) must be free of marine mammals during that time.

For any other in-water construction heavy machinery activities ( e.g., trenching, cable laying, etc.), if a marine mammal is on a path towards or comes within 10 m (32.8 ft) of equipment, Atlantic Shores would be required to cease operations until the marine mammal has moved more than 10 m on a path away from the activity to avoid direct interaction with equipment.

Once an activity begins, any marine mammal entering their respective shutdown zone would trigger the activity to cease. In the case of pile driving, the shutdown requirement may be waived if is not practicable due to imminent risk of injury or loss of life to an individual or risk of damage to a vessel that creates risk of injury or loss of life for individuals or the lead engineer determines there is pile refusal or pile instability.

In situations when shutdown is called for but Atlantic Shores determines shutdown is not practicable due to aforementioned emergency reasons, reduced hammer energy must be implemented when the lead engineer determines it is practicable. Specifically, pile refusal or pile instability could result in not being able to shut down pile driving immediately. Pile refusal occurs when the pile driving sensors indicate the pile is approaching refusal, and a shut-down would lead to a stuck pile which then poses an imminent risk of injury or loss of life to an individual, or risk of damage to a vessel that creates risk for individuals. Pile instability occurs when the pile is unstable and unable to stay standing if the piling vessel were to “let go.” During these periods of instability, the lead engineer may determine a shut-down is not feasible because the shut-down combined with impending weather conditions may require the piling vessel to “let go” which then poses an imminent risk of injury or loss of life to an individual, or risk of damage to a vessel that creates risk for individuals. Atlantic Shores must document and report to NMFS all cases where the emergency exemption is taken.

After shutdown, impact pile driving may be reinitiated once all clearance zones are clear of marine mammals for the minimum species-specific periods, or, if required to maintain pile stability, impact pile driving may be reinitiated but must be used to maintain stability. If pile driving has been shut down due to the presence of a North Atlantic right whale, pile driving must not restart until the North Atlantic right whale has neither been visually or acoustically detected for30 minutes. Upon re-starting pile driving, soft-start protocols must be followed if pile driving has ceased for 30 minutes or longer.

The clearance and shutdown zone sizes vary by species and are shown in Table 27, Table 28, and Table 29. Atlantic Shores would be allowed to request modification to these zone sizes pending results of sound field verification (see regulatory text at the end of this proposed rulemaking). Any changes to zone size would be part of adaptive management and would require NMFS' approval.

Soft-Start/Ramp-Up

The use of a soft-start or ramp-up procedure is believed to provide additional protection to marine mammals by warning them, or providing them with a chance to leave the area prior to the hammer or HRG equipment operating at full capacity. Soft-start typically involves initiating hammer operation at a reduced energy level (relative to full operating capacity) followed by a waiting period. Atlantic Shores would be required to utilize a soft-start protocol for impact pile driving of monopiles and pin piles by performing four to six strikes per minute at 10 to 20 percent of the maximum hammer energy, for a minimum of 20 minutes. NMFS notes that it is difficult to specify a reduction in energy for any given hammer because of variation across drivers and installation conditions. Atlantic Shores will reduce energy based on consideration of site-specific soil properties and other relevant operational considerations. A soft-start during vibratory pile driving of sheet piles would be accomplished by varying hammer frequency and/or amplitude. The final methodology will be developed by Atlantic Shores considering final design details including site specific soil properties and other considerations. HRG survey operators would be required to ramp-up sources when the acoustic sources are used unless the equipment operates on a binary on/off switch. The ramp up would involve starting from the smallest setting to the operating level over a period of approximately 30 minutes.

Soft-start and ramp-up would be required at the beginning of each day's activity and at any time following a cessation of activity of 30 minutes or longer. Prior to soft-start or ramp-up beginning, the operator must receive confirmation from the PSO that the clearance zone is clear of any marine mammals.

Fishery Monitoring Surveys

While the likelihood of Atlantic Shores' fishery monitoring surveys impacting marine mammals is minimal, NMFS proposed to require Atlantic Shores to adhere to gear and vessel mitigation measures to reduce potential impacts to the extent practicable. In addition, all crew undertaking the fishery monitoring survey activities would be required to receive protected species identification training prior to activities occurring and attend the aforementioned onboarding training. The specific requirements that NMFS would set for the fishery monitoring surveys can be found in the regulatory text at the end of this proposed rulemaking.

Based on our evaluation of the mitigation measures, as well as other measures considered by NMFS, NMFS has preliminarily determined that these proposed measures would provide the means of affecting the least practicable adverse impact on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

In order to promulgate a rulemaking for an activity, section 101(a)(5)(A) of the MMPA states that NMFS must set forth requirements pertaining to the monitoring and reporting of such taking. The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for authorizations must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present in the proposed action area. Effective reporting is critical both to compliance as well as ensuring that the most value is obtained from the required monitoring.

• Monitoring and reporting requirements prescribed by NMFS should contribute to improved understanding of one or more of the following:

• Occurrence of marine mammal species or stocks in the area in which take is anticipated ( e.g., presence, abundance, distribution, density);

• Nature, scope, or context of likely marine mammal exposure to potential stressors/impacts (individual or cumulative, acute or chronic), through better understanding of: (1) action or environment ( e.g., source characterization, propagation, ambient noise); (2) affected species ( e.g., life history, dive patterns); (3) co-occurrence of marine mammal species with the action; or (4) biological or behavioral context of exposure ( e.g., age, calving or feeding areas);

• Individual marine mammal responses (behavioral or physiological) to acoustic stressors (acute, chronic, or cumulative), other stressors, or cumulative impacts from multiple stressors;
• How anticipated responses to stressors impact either: (1) long-term fitness and survival of individual marine mammals; or (2) populations, species, or stocks;

• Effects on marine mammal habitat ( e.g., marine mammal prey species, acoustic habitat, or other important physical components of marine mammal habitat); and/or

• Mitigation and monitoring effectiveness.

Separately, monitoring is also regularly used to support mitigation implementation, which is referred to as mitigation monitoring, and monitoring plans typically include measures that both support mitigation implementation and increase our understanding of the impacts of the activity on marine mammals.

During the planned activities, visual monitoring by NMFS-approved PSOs would be conducted before, during, and after all impact pile driving, vibratory pile driving, and HRG surveys. PAM would be also conducted during impact pile driving. Visual observations and acoustic detections would be used to support the activity-specific mitigation measures ( e.g., clearance zones). To increase understanding of the impacts of the activity on marine mammals, PSOs must would record all incidents of marine mammal occurrence at any distance from the piling locations, near the HRG acoustic sources. PSOs would document all behaviors and behavioral changes, in concert with distance from an acoustic source. The required monitoring is described below, beginning with PSO measures that are applicable to all the aforementioned activities, followed by activity-specific monitoring requirements.

Protected Species Observer and PAM Operator Requirements

Atlantic Shores would be required to employ NMFS-approved PSOs and PAM operators. PSOs are trained professionals who are tasked with visually monitoring for marine mammals during pile driving and HRG surveys. The primary purpose of a PSO is to carry out the monitoring, collect data, and, when appropriate, call for the implementation of mitigation measures. In addition to visual observations, NMFS would require Atlantic Shores to conduct PAM using PAM operators during impact pile driving and vessel transit.

The inclusion of PAM, which would be conducted by NMFS-approved PAM operators, following a standardized measurement, processing methods, reporting metrics, and metadata standards for offshore wind alongside visual data collection is valuable to provide the most accurate record of species presence as possible, together, and these two monitoring methods are well understood to provide best results when combined together ( e.g., Barlow and Taylor, 2005; Clark et al., 2010; Gerrodette et al., 2011; Van Parijs et al., 2021). Acoustic monitoring (in addition to visual monitoring) increases the likelihood of detecting marine mammals within the shutdown and clearance zones of project activities, which when applied in combination with required shutdowns helps to further reduce the risk of marine mammals being exposed to sound levels that could otherwise result in acoustic injury or more intense behavioral harassment.

The exact configuration and number of PAM systems depends on the size of the zone(s) being monitored, the amount of noise expected in the area, and the characteristics of the signals being monitored. More closely spaced hydrophones would allow for more directionality, and perhaps, range to the vocalizing marine mammals; although, this approach would add additional costs and greater levels of complexity to the project. Larger baleen cetacean species ( i.e., mysticetes), which produce loud and lower-frequency vocalizations, may be able to be heard with fewer hydrophones spaced at greater distances. However, smaller cetaceans (such as mid-frequency delphinids; odontocetes) may necessitate more hydrophones and to be spaced closer together given the shorter range of the shorter, mid-frequency acoustic signals ( e.g., whistles and echolocation clicks). As there are no “perfect fit” single-optimal-array configurations, NMFS will consider and approve these set-ups, as appropriate, on a case-by-case basis. Specifically, Atlantic Shores will be required to provide a plan that describes an optimal configuration for collecting the required marine mammal data, based on the real world circumstances in the project area, recognizing that we will continue to learn more as monitoring results from other wind projects are submitted.

NMFS does not formally administer any PSO or PAM operator training program or endorse specific providers but will approve PSOs and PAM operators that have successfully completed courses that meet the curriculum and trainer requirements referenced below and further specified in the regulatory text at the end of this proposed rulemaking.

NMFS will provide PSO and PAM operator approvals in the context of the need to ensure that PSOs and PAM operators have the necessary training and/or experience to carry out their duties competently. In order for PSOs and PAM operators to be approved, NMFS must review and approve PSO and PAM operator resumes indicating successful completion of an acceptable training course. PSOs and PAM operators must have previous experience observing marine mammals and must have the ability to work with all required and relevant software and equipment. NMFS may approve PSOs and PAM operators as conditional or unconditional. A conditional approval may be given to one who is trained but has not yet attained the requisite experience. An unconditional approval is given to one who is trained and has attained the necessary experience. The specific requirements for conditional and unconditional approval can be found in the regulatory text at the end of this proposed rulemaking.

Conditionally-approved PSOs and PAM operators would be paired with an unconditionally-approved PSO (or PAM operator, as appropriate) to ensure that the quality of marine mammal observations and data recording is kept consistent. Additionally, activities requiring PSO and/or PAM operator monitoring must have a lead on duty. The visual PSO field team, in conjunction with the PAM team ( i.e., marine mammal monitoring team) would have a lead member (designated as the “Lead PSO” or “Lead PAM operator”) who would be required to meet the unconditional approval standard.

Although PSOs and PAM operators must be approved by NMFS, third-party observer providers and/or companies seeking PSO and PAM operator staffing should expect that those having satisfactorily completed acceptable training and with the requisite experience (if required) will be quickly approved. Atlantic Shores is required to request PSO and PAM operator approvals 60 days prior to those personnel commencing work. An initial list of previously approved PSO and PAM operators must be submitted by Atlantic Shores at least 30 days prior to the start of the project. Should Atlantic Shores require additional PSOs or PAM operators throughout the project, Atlantic Shores must submit a subsequent list of pre-approved PSOs and PAM operators to NMFS at least 15 days prior to planned use of that PSO or PAM operator. A PSO may be trained and/or experienced as both a PSO and PAM operator and may perform either duty, pursuant to scheduling requirements (and vice versa).

A minimum number of PSOs would be required to actively observe for the presence of marine mammals during certain project activities with more PSOs required as the mitigation zone sizes increase. A minimum number of PAM operators would be required to actively monitor for the presence of marine mammals during foundation installation. The types of equipment required ( e.g., Big Eye binoculars on the pile driving vessel) are also designed to increase marine mammal detection capabilities. Specifics on these types of requirements can be found in the regulations at the end of this proposed rulemaking. In summary, at least three PSOs and one PAM operator per acoustic data stream (equivalent to the number of acoustic buoys) must be on-duty and actively monitoring per platform during foundation installation; at least two PSOs must be on duty during cable landfall construction vibratory pile installation and removal; at least one PSO must be on-duty during HRG surveys conducted during daylight hours; and at least two PSOs must be on-duty during HRG surveys conducted during nighttime.

In addition to monitoring duties, PSOs and PAM operators are responsible for data collection. The data collected by PSO and PAM operators and subsequent analysis provide the necessary information to inform an estimate of the amount of take that occurred during the project, better understand the impacts of the project on marine mammals, address the effectiveness of monitoring and mitigation measures, and to adaptively manage activities and mitigation in the future. Data reported includes information on marine mammal sightings, activity occurring at time of sighting, monitoring conditions, and if mitigative actions were taken. Specific data collection requirements are contained within the regulations at the end of this proposed rulemaking.

Atlantic Shores would be required to submit a Pile Driving Marine Mammal Monitoring Plan and a PAM Plan to NMFS 180 days in advance of foundation installation activities. The Plan must include details regarding PSO and PAM monitoring protocols and equipment proposed for use. More specifically, the PAM Plan must include a description of all proposed PAM equipment, address how the proposed passive acoustic monitoring must follow standardized measurement, processing methods, reporting metrics, and metadata standards for offshore wind as described in NOAA and BOEM Minimum Recommendations for Use of Passive Acoustic Listening Systems in Offshore Wind Energy Development Monitoring and Mitigation Programs (Van Parijs et al., 2021). NMFS must approve the plan prior to foundation installation activities commencing. Specific details on NMFS' PSO or PAM operator qualifications and requirements can be found in Part 217—Regulations Governing The Taking And Importing Of Marine Mammals at the end of this proposed rulemaking. Additional information can be found in Atlantic Shores' Protected Species Management and Equipment Specifications Plan (PSMESP; Appendix E) found in their ITA application on NMFS' website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-atlantic-shores-offshore-wind-llc-construction-atlantic-shores.

Sound Field Verification

Atlantic Shores would be required to conduct SFV measurements during all impact pile-driving activities associated with the installation of, at minimum, the first three monopile foundations. SFV measurements must continue until at least three consecutive monopiles and three entire jacket foundations demonstrate noise levels are at or below those modeled, assuming 10-decibels (dB) of attenuation. Subsequent SFV measurements would also be required should larger piles be installed or if additional piles are driven that are anticipated to produce louder sound fields than those previously measured ( e.g., higher hammer energy, greater number of strikes, etc.). The measurements and reporting associated with SFV can be found in the regulatory text at the end of this proposed rulemaking. The proposed requirements are extensive to ensure monitoring is conducted appropriately and the reporting frequency is such that Atlantic Shores would be required to make adjustments quickly ( e.g., add additional sound attenuation) to ensure marine mammals are not experiencing noise levels above those considered in this analysis. For recommended SFV protocols for impact pile driving, please consult ISO 18406 Underwater acoustics—Measurement of radiated underwater sound from percussive pile driving (2017).

Reporting

Prior to any construction activities occurring, Atlantic Shores would provide a report to NMFS Office of Protected Resources that demonstrates that all required training for Atlantic Shores personnel, which includes the vessel crews, vessel captains, PSOs, and PAM operators have completed all required trainings.

NMFS would require standardized and frequent reporting from Atlantic Shores during the life of the regulations and LOA. All data collected relating to the Project would be recorded using industry-standard software ( e.g., Mysticetus or a similar software) installed on field laptops and/or tablets. Atlantic Shores would be required to submit weekly, monthly, annual, and situational reports. The specifics of what we require to be reported can be found in the regulatory text at the end of this proposed rulemaking.

Weekly Report —During foundation installation activities, Atlantic Shores would be required to compile and submit weekly marine mammal monitoring reports for foundation installation pile driving to NMFS Office of Protected Resources that document the daily start and stop of all pile-driving activities, the start and stop of associated observation periods by PSOs, details on the deployment of PSOs, a record of all detections of marine mammals (acoustic and visual), any mitigation actions (or if mitigation actions could not be taken, provide reasons why), and details on the noise abatement system(s) ( e.g., system type, distance deployed from the pile, bubble rate, etc.). Weekly reports will be due on Wednesday for the previous week (Sunday to Saturday). The weekly reports are also required to identify which turbines become operational and when (a map must be provided). Once all foundation pile installation is complete, weekly reports would no longer be required.

Monthly Report —Atlantic Shores would be required to compile and submit monthly reports to NMFS Office of Protected Resources that include a summary of all information in the weekly reports, including project activities carried out in the previous month, vessel transits (number, type of vessel, and route), number of piles installed, all detections of marine mammals, and any mitigative actions taken. Monthly reports would be due on the 15th of the month for the previous month. The monthly report would also identify which turbines become operational and when (a map must be provided). Once all foundation pile installation is complete, monthly reports would no longer be required.

Annual Reporting —Atlantic Shores would be required to submit an annual marine mammal monitoring (both PSO and PAM) report to NMFS Office of Protected Resources no later than 90 days following the end of a given calendar year describing, in detail, all of the information required in the monitoring section above. A final annual report must be prepared and submitted within 30 calendar days following receipt of any NMFS comments on the draft report.

Final 5-Year Reporting —Atlantic Shores would be required to submit its draft 5-year report(s) to NMFS Office of Protected Resources on all visual and acoustic monitoring conducted under the LOA within 90 calendar days of the completion of activities occurring under the LOA. A final 5-year report must be prepared and submitted within 60 calendar days following receipt of any NMFS comments on the draft report. Information contained within this report is described at the beginning of this section.

Situational Reporting —Specific situations encountered during the development of the Project would require immediate reporting. For instance, if a North Atlantic right whale is observed at any time by PSOs or project personnel, the sighting must be immediately (if not feasible, as soon as possible and no longer than 24 hours after the sighting) reported to NMFS. If a North Atlantic right whale is acoustically detected at any time via a project-related PAM system, the detection must be reported as soon as possible and no longer than 24 hours after the detection to NMFS via the 24-hour North Atlantic right whale Detection Template ( https://www.fisheries.noaa.gov/resource/document/passive-acoustic-reporting-system-templates ). Calling the hotline is not necessary when reporting PAM detections via the template.

If a sighting of a stranded, entangled, injured, or dead marine mammal occurs, the sighting would be reported to NMFS Office of Protected Resources, the NMFS Greater Atlantic Stranding Coordinator for the New England/Mid-Atlantic area (866–755–6622), and the U.S. Coast Guard within 24 hours. If the injury or death was caused by a project activity, Atlantic Shores would be required to immediately cease all activities until NMFS Office of Protected Resources is able to review the circumstances of the incident and determine what, if any, additional measures are appropriate to ensure compliance with the terms of the LOA. NMFS Office of Protected Resources may impose additional measures to minimize the likelihood of further prohibited take and ensure MMPA compliance consistent with the adaptive management provisions described below and codified at § 217.307. Atlantic shores could not resume their activities until notified by NMFS Office of Protected Resources.

In the event of a vessel strike of a marine mammal by any vessel associated with the Project. Atlantic Shores must immediately report the strike incident. If the strike occurs in the Greater Atlantic Region (Maine to Virginia), Atlantic Shores must call the NMFS Office of Protected Resources and GARFO. Atlantic Shores would be required to immediately cease all on-water activities until NMFS Office of Protected Resources is able to review the circumstances of the incident and determine what, if any, additional measures are appropriate to ensure compliance with the terms of the LOA. NMFS Office of Protected Resources may impose additional measures to minimize the likelihood of further prohibited take and ensure MMPA compliance. Atlantic Shores may, consistent with the adaptive management provisions described below and codified at § 217.307, not resume their activities until notified by NMFS.

In the event of any lost gear associated with the fishery surveys, Atlantic Shores must report to the GARFO as soon as possible or within 24 hours of the documented time of missing or lost gear. This report must include information on any markings on the gear and any efforts undertaken or planned to recover the gear.

The specifics of what NMFS Office of Protected Resources requires to be reported is listed at the end of this proposed rulemaking in the regulatory text.

Sound Field Verification —Atlantic Shores would be required to submit interim SFV reports after each foundation installation is completed as soon as possible but within 48 hours. A final SFV report for all monopile and jacket foundation installation monitoring would be required within 90 days following completion of acoustic monitoring.

Adaptive Management

The regulations governing the take of marine mammals incidental to Atlantic Shores' construction activities contain an adaptive management component. Our understanding of the effects of offshore wind construction activities ( e.g., acoustic stressors) on marine mammals continues to evolve, which makes the inclusion of an adaptive management component both valuable and necessary within the context of 5-year regulations.

The monitoring and reporting requirements in this final rule provide NMFS with information that helps us to better understand the impacts of the project's activities on marine mammals and informs our consideration of whether any changes to mitigation and monitoring are appropriate. The use of adaptive management allows NMFS to consider new information and modify mitigation, monitoring, or reporting requirements, as appropriate, with input from Atlantic Shores regarding practicability, if such modifications will have a reasonable likelihood of more effectively accomplishing the goal of the measures.

The following are some of the possible sources of new information to be considered through the adaptive management process: (1) results from monitoring reports, including the weekly, monthly, situational, and annual reports required; (2) results from marine mammal and sound research; and (3) any information which reveals that marine mammals may have been taken in a manner, extent, or number not authorized by these regulations or subsequent LOA. During the course of the rule, Atlantic Shores (and other LOA Holders conducting offshore wind development activities) are required to participate in one or more adaptive management meetings convened by NMFS and/or BOEM, in which the above information will be summarized and discussed in the context of potential changes to the mitigation or monitoring measures.

Negligible Impact Analysis and Determination

NMFS has defined negligible impact as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival (50 CFR 216.103). A negligible impact finding is based on the lack of likely adverse effects on annual rates of recruitment or survival ( i.e., population-level effects). An estimate of the number of takes alone is not enough information on which to base an impact determination. In addition to considering estimates of the number of marine mammals that might be “taken” by mortality, serious injury, Level A harassment and Level B harassment, we consider other factors, such as the likely nature of any behavioral responses ( e.g., intensity, duration), the context of any such responses ( e.g., critical reproductive time or location, migration), as well as effects on habitat, and the likely effectiveness of mitigation. We also assess the number, intensity, and context of estimated takes by evaluating this information relative to population status. Consistent with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, September 29, 1989), the impacts from other past and ongoing anthropogenic activities are incorporated into this analysis via their impacts on the environmental baseline ( e.g., as reflected in the regulatory status of the species, population size and growth rate where known, ongoing sources of human-caused mortality, or ambient noise levels).

In the Estimated Take section, we estimated the maximum number of takes by Level A harassment and Level B harassment that could occur from Atlantic Shores' specified activities based on the methods described. The impact that any given take would have is dependent on many case-specific factors that need to be considered in the negligible impact analysis ( e.g., the context of behavioral exposures such as duration or intensity of a disturbance, the health of impacted animals, the status of a species that incurs fitness-level impacts to individuals, etc.). In this proposed rule, we evaluate the likely impacts of the enumerated harassment takes that are authorized in the context of the specific circumstances surrounding these predicted takes. We also collectively evaluate this information, as well as other more taxa-specific information and mitigation measure effectiveness, in group-specific discussions that support our negligible impact conclusions for each stock. As described above, no serious injury or mortality is expected or proposed to be authorized for any species or stock.

The Description of the Specified Activities section describes Atlantic Shores' specified activities proposed for the project that may result in take of marine mammals and an estimated schedule for conducting those activities. Atlantic Shores South has provided a realistic construction schedule although we recognize schedules may shift for a variety of reasons ( e.g., weather or supply delays). However, the total amount of take would not exceed the 5-year totals and maximum annual total in any given year indicated in Tables 25 and 26, respectively.

We base our analysis and preliminary negligible impact determination on the maximum number of takes that could occur and are proposed to be authorized annually and across the effective period of these regulations, and extensive qualitative consideration of other contextual factors that influence the degree of impact of the takes on the affected individuals and the number and context of the individuals affected. As stated before, the number of takes, both maximum annual and 5-year total, alone are only a part of the analysis.

To avoid repetition, we provide some general analysis in this Negligible Impact Analysis and Determination section that applies to all the species listed in Table 4 given that some of the anticipated effects of Atlantic Shores' construction activities on marine mammals are expected to be relatively similar in nature. Then, we subdivide into more detailed discussions for mysticetes, odontocetes, and pinnipeds which have broad life history traits that support an overarching discussion of some factors considered within the analysis for those groups ( e.g., habitat-use patterns, high-level differences in feeding strategies).

Last, we provide a negligible impact determination for each species or stock, providing species or stock-specific information or analysis, where appropriate, for example, for North Atlantic right whales given the population status. Organizing our analysis by grouping species or stocks that share common traits or that would respond similarly to effects of Atlantic Shores' activities, and then providing species- or stock-specific information allows us to avoid duplication while ensuring that we have analyzed the effects of the specified activities on each affected species or stock. It is important to note that in the group or species sections, we base our negligible impact analysis on the maximum annual take that is predicted under the 5-year rule; however, the majority of the impacts are associated with WTG, Met Tower, and OSS foundation installation, which would occur largely within the first 2 to 3 years (2025 through 2026 or 2027). The estimated take in the other years is expected to be notably less, which is reflected in the total take that would be allowable under the rule (see Tables 24, 25, and 26).

As described previously, no serious injury or mortality is anticipated or authorized in this rule. Any Level A harassment authorized would be in the form of auditory injury ( i.e., PTS) and not non-auditory injury ( e.g., lung injury or gastrointestinal injury from detonations). The amount of harassment Atlantic Shores has requested, and NMFS proposes to authorize, is based on exposure models that consider the outputs of acoustic source and propagation models and other data such as frequency of occurrence or group sizes. Several conservative parameters and assumptions are ingrained into these models, such as assuming forcing functions that consider direct contact with piles ( i.e., no cushion allowances) and application of the average summer sound speed profile to all months within a given season. The exposure model results do not reflect any mitigation measures (other than 10-dB sound attenuation) or avoidance response. The amount of take requested and proposed to be authorized also reflects careful consideration of other data ( e.g., group size data) and, for Level A harassment potential of some large whales, the consideration of mitigation measures. For all species, the amount of take proposed to be authorized represents the maximum amount of Level A harassment and Level B harassment that could occur.

Behavioral Disturbance

In general, NMFS anticipates that impacts on an individual that has been harassed are likely to be more intense when exposed to higher received levels and for a longer duration (though this is in no way a strictly linear relationship for behavioral effects across species, individuals, or circumstances) and less severe impacts result when exposed to lower received levels and for a brief duration. However, there is also growing evidence of the importance of contextual factors such as distance from a source in predicting marine mammal behavioral response to sound— i.e., sounds of a similar level emanating from a more distant source have been shown to be less likely to evoke a response of equal magnitude (DeRuiter and Doukara, 2012; Falcone et al., 2017). As described in the Potential Effects of Specified Activities on Marine Mammals and their Habitat section, the intensity and duration of any impact resulting from exposure to Atlantic Shores' activities is dependent upon a number of contextual factors including, but not limited to, sound source frequencies, whether the sound source is moving towards the animal, hearing ranges of marine mammals, behavioral state at time of exposure, status of individual exposed ( e.g., reproductive status, age class, health) and an individual's experience with similar sound sources. Southall et al. (2021), Ellison et al. (2012) and Moore and Barlow (2013), among others, emphasize the importance of context ( e.g., behavioral state of the animals, distance from the sound source) in evaluating behavioral responses of marine mammals to acoustic sources. Harassment of marine mammals may result in behavioral modifications ( e.g., avoidance, temporary cessation of foraging or communicating, changes in respiration or group dynamics, masking) or may result in auditory impacts such as hearing loss. In addition, some of the lower level physiological stress responses ( e.g., change in respiration, change in heart rate) discussed previously would likely co-occur with the behavioral modifications, although these physiological responses are more difficult to detect and fewer data exist relating these responses to specific received levels of sound. Takes by Level B harassment, then, may have a stress-related physiological component as well. However, we would not expect Atlantic Shores' activities to produce conditions of long-term and continuous exposure to noise leading to long-term physiological stress responses in marine mammals that could affect reproduction or survival.

In the range of behavioral effects that might be expected to be part of a response that qualifies as an instance of Level B harassment by behavioral disturbance (which by nature of the way it is modeled/counted, occurs within 1 day), the less severe end might include exposure to comparatively lower levels of a sound, at a greater distance from the animal, for a few or several minutes. A less severe exposure of this nature could result in a behavioral response such as avoiding an area that an animal would otherwise have chosen to move through or feed in for some amount of time, or breaking off one or a few feeding bouts. More severe effects could occur if an animal gets close enough to the source to receive a comparatively higher level, is exposed continuously to one source for a longer time, or is exposed intermittently to different sources throughout a day. Such effects might result in an animal having a more severe flight response and leaving a larger area for a day or more or potentially losing feeding opportunities for a day. However, such severe behavioral effects are expected to occur infrequently.

Many species perform vital functions, such as feeding, resting, traveling, and socializing on a diel cycle (24-hour cycle). Behavioral reactions to noise exposure, when taking place in a biologically important context, such as disruption of critical life functions, displacement, or avoidance of important habitat, are more likely to be significant if they last more than 1 day or recur on subsequent days (Southall et al., 2007) due to diel and lunar patterns in diving and foraging behaviors observed in many cetaceans (Baird et al., 2008; Barlow et al., 2020; Henderson et al., 2016; Schorr et al., 2014). It is important to note the water depth in the Project Area is shallow (ranging up to 30 m in the ECRs, and 19 to 37 m in the Lease Area) and deep diving species, such as sperm whales, are not expected to be engaging in deep foraging dives when exposed to noise above NMFS harassment thresholds during the specified activities. Therefore, we do not anticipate impacts to deep foraging behavior to be impacted by the specified activities.

It is also important to identify that the estimated number of takes does not necessarily equate to the number of individual animals Atlantic Shores expects to harass (which is lower), but rather to the instances of take ( i.e., exposures above the Level B harassment thresholds) that may occur. These instances may represent either seconds to minutes for HRG surveys, or, in some cases, longer durations of exposure within a day ( e.g., pile driving). Some individuals of a species may experience recurring instances of take over multiple days throughout the year while some members of a species or stock may experience one exposure as they move through an area, which means that the number of individuals taken is smaller than the total estimated takes. In short, for species that are more likely to be migrating through the area and/or for which only a comparatively smaller number of takes are predicted ( e.g., some of the mysticetes), it is more likely that each take represents a different individual. Whereas for non-migrating species with larger amounts of predicted take, we expect that the total anticipated takes represent exposures of a smaller number of individuals of which some would be taken across multiple days.

For Atlantic Shores, impact pile driving of foundation piles is most likely to result in a higher magnitude and severity of behavioral disturbance than other activities ( i.e., vibratory pile driving and HRG surveys). Impact pile driving has higher source levels and longer durations (on an annual basis) than vibratory pile driving and HRG surveys. HRG survey equipment also produces much higher frequencies than pile driving, resulting in minimal sound propagation. While impact pile driving for foundation installation is anticipated to be most impactful for these reasons, impacts are minimized through implementation of mitigation measures, including use of a sound attenuation system, soft-starts, the implementation of clearance zones that would facilitate a delay to pile-driving commencement, and implementation of shutdown zones. All these measures are designed to avoid or minimize harassment. For example, given sufficient notice through the use of soft-start, marine mammals are expected to move away from a sound source that is disturbing prior to becoming exposed to very loud noise levels. The requirement to couple visual monitoring and PAM before and during all foundation installation will increase the overall capability to detect marine mammals compared to one method alone.

Occasional, milder behavioral reactions are unlikely to cause long-term consequences for individual animals or populations, and even if some smaller subset of the takes are in the form of a longer (several hours or a day) and more severe response, if they are not expected to be repeated over numerous or sequential days, impacts to individual fitness are not anticipated. Also, the effect of disturbance is strongly influenced by whether it overlaps with biologically important habitats when individuals are present—avoiding biologically important habitats will provide opportunities to compensate for reduced or lost foraging (Keen et al., 2021). Nearly all studies and experts agree that infrequent exposures of a single day or less are unlikely to impact an individual's overall energy budget (Farmer et al., 2018; Harris et al., 2017; King et al., 2015; National Academy of Science, 2017; New et al., 2014; Southall et al., 2007; Villegas-Amtmann et al., 2015).

Temporary Threshold Shift (TTS)

TTS is one form of Level B harassment that marine mammals may incur through exposure to Atlantic Shores' activities and, as described earlier, the proposed takes by Level B harassment may represent takes in the form of behavioral disturbance, TTS, or both. As discussed in the Potential Effects of Specified Activities on Marine Mammals and their Habitat section, in general, TTS can last from a few minutes to days, be of varying degree, and occur across different frequency bandwidths, all of which determine the severity of the impacts on the affected individual, which can range from minor to more severe. Impact and vibratory pile driving are broadband noise sources but generate sounds in the lower frequency ranges (with most of the energy below 1–2 kHz, but with a small amount energy ranging up to 20 kHz). Therefore, in general and all else being equal, we would anticipate the potential for TTS is higher in low-frequency cetaceans ( i.e., mysticetes) than other marine mammal hearing groups and would be more likely to occur in frequency bands in which they communicate. However, we would not expect the TTS to span the entire communication or hearing range of any species given that the frequencies produced by these activities do not span entire hearing ranges for any particular species. Additionally, though the frequency range of TTS that marine mammals might sustain would overlap with some of the frequency ranges of their vocalizations, the frequency range of TTS from Atlantic Shores' pile driving activities would not typically span the entire frequency range of one vocalization type, much less span all types of vocalizations or other critical auditory cues for any given species. However, the proposed mitigation measures further reduce the potential for TTS in mysticetes.

Generally, both the degree of TTS and the duration of TTS would be greater if the marine mammal is exposed to a higher level of energy (which would occur when the peak dB level is higher or the duration is longer). The threshold for the onset of TTS was discussed previously (refer back to Estimated Take). However, source level alone is not a predictor of TTS. An animal would have to approach closer to the source or remain in the vicinity of the sound source appreciably longer to increase the received SEL, which would be difficult considering the proposed mitigation and the nominal speed of the receiving animal relative to the stationary sources such as impact pile driving. The recovery time of TTS is also of importance when considering the potential impacts from TTS. In TTS laboratory studies (as discussed in Potential Effects of Specified Activities on Marine Mammals and Their Habitat), some using exposures of almost an hour in duration or up to 217 SEL, almost all individuals recovered within 1 day (or less, often in minutes), and we note that while the pile-driving activities last for hours a day, it is unlikely that most marine mammals would stay in the close vicinity of the source long enough to incur more severe TTS. Overall, given the small number of time that any individual might incur TTS, the low degree of TTS and the short anticipated duration, and the unlikely scenario that any TTS overlapped the entirety of a critical hearing range, it is unlikely that TTS (of the nature expected to result from the project's activities) would result in behavioral changes or other impacts that would impact any individual's (of any hearing sensitivity) reproduction or survival.

Permanent Threshold Shift (PTS)

NMFS proposes to authorize, a very small amount of take by PTS to some marine mammal individuals. The numbers of proposed annual takes by Level A harassment are relatively low for all marine mammal stocks and species (Table 25). The only activities incidental to which we anticipate PTS may occur is from exposure to impact pile driving, which produces sounds that are both impulsive and primarily concentrated in the lower frequency ranges (below 1 kHz) (David, 2006; Krumpel et al., 2021).

There are no PTS data on cetaceans and only one instance of PTS being induced in older harbor seals (Reichmuth et al., 2019). However, available TTS data (of mid-frequency hearing specialists exposed to mid- or high-frequency sounds (Southall et al., 2007; NMFS, 2018; Southall et al., 2019)) suggest that most threshold shifts occur in the frequency range of the source up to one octave higher than the source. We would anticipate a similar result for PTS. Further, no more than a small degree of PTS is expected to be associated with any of the incurred Level A harassment, given it is unlikely that animals would stay in the close vicinity of a source for a duration long enough to produce more than a small degree of PTS.

PTS would consist of minor degradation of hearing capabilities occurring predominantly at frequencies one-half to one octave above the frequency of the energy produced by pile driving ( i.e., the low-frequency region below 2 kHz) (Cody and Johnstone, 1981; McFadden, 1986; Finneran, 2015), not severe hearing impairment. If hearing impairment occurs from impact pile driving, it is most likely that the affected animal would lose a few decibels in its hearing sensitivity, which in most cases is not likely to meaningfully affect its ability to forage and communicate with conspecifics. In addition, during impact pile driving, given sufficient notice through use of soft-start prior to implementation of full hammer energy during impact pile driving, marine mammals are expected to move away from a sound source that is disturbing prior to it resulting in severe PTS.

Auditory Masking or Communication Impairment

The ultimate potential impacts of masking on an individual are similar to those discussed for TTS ( e.g., decreased ability to communicate, forage effectively, or detect predators), but an important difference is that masking only occurs during the time of the signal, versus TTS, which continues beyond the duration of the signal. Also, though masking can result from the sum of exposure to multiple signals, none of which might individually cause TTS. Fundamentally, masking is referred to as a chronic effect because one of the key potential harmful components of masking is its duration—the fact that an animal would have reduced ability to hear or interpret critical cues becomes much more likely to cause a problem the longer it is occurring. Inherent in the concept of masking is the fact that the potential for the effect is only present during the times that the animal and the source are in close enough proximity for the effect to occur (and further, this time period would need to coincide with a time that the animal was utilizing sounds at the masked frequency).

As our analysis has indicated, for this project we expect that impact pile driving foundations have the greatest potential to mask marine mammal signals, and this pile driving may occur for several, albeit intermittent, hours per day, for multiple days per year. Masking is fundamentally more of a concern at lower frequencies (which are pile-driving dominant frequencies), because low frequency signals propagate significantly further than higher frequencies and because they are more likely to overlap both the narrower low frequency calls of mysticetes, as well as many non-communication cues related to fish and invertebrate prey, and geologic sounds that inform navigation. However, the area in which masking would occur for all marine mammal species and stocks ( e.g., predominantly in the vicinity of the foundation pile being driven) is small relative to the extent of habitat used by each species and stock. In summary, the nature of Atlantic Shores' activities, paired with habitat use patterns by marine mammals, does not support the likelihood that the level of masking that could occur would have the potential to affect reproductive success or survival. Therefore, we are not predicting take due to masking effects, and are not proposing to authorize such take.

Impacts on Habitat and Prey

Construction activities may result in fish and invertebrate mortality or injury very close to the source, and all of Atlantic Shores' activities may cause some fish to leave the area of disturbance. It is anticipated that any mortality or injury would be limited to a very small subset of available prey and the implementation of mitigation measures such as the use of a noise attenuation system during impact pile driving would further limit the degree of impact. Behavioral changes in prey in response to construction activities could temporarily impact marine mammals' foraging opportunities in a limited portion of the foraging range but, because of the relatively small area of the habitat that may be affected at any given time ( e.g., around a pile being driven), the impacts to marine mammal habitat are not expected to cause significant or long-term negative consequences.

Cable presence is not anticipated to impact marine mammal habitat as these would be buried, and any electromagnetic fields emanating from the cables are not anticipated to result in consequences that would impact marine mammals' prey to the extent they would be unavailable for consumption.

The presence of wind turbines within the Lease Area could have longer-term impacts on marine mammal habitat, as the project would result in the persistence of the structures within marine mammal habitat for more than 30 years. The presence of structures such as wind turbines is, in general, likely to result in certain oceanographic effects in the marine environment, and may alter aggregations and distribution of marine mammal zooplankton prey through changing the strength of tidal currents and associated fronts, changes in stratification, primary production, the degree of mixing, and stratification in the water column (Schultze et al., 2020; Chen et al., 2021; Johnson et al., 2021; Christiansen et al., 2022; Dorrell et al., 2022).

As discussed in the Potential Effects of Specified Activities on Marine Mammals and their Habitat section, the project would consist of no more than 211 foundations (200 WTGs, 10 OSS, 1 Met Tower) in the Lease Area, which will gradually become operational following construction completion. While there are likely to be oceanographic impacts from the presence of operating turbines, meaningful oceanographic impacts relative to stratification and mixing that would significantly affect marine mammal habitat and prey over large areas in key foraging habitats are not anticipated from the Atlantic Shores activities covered under these proposed regulations. For these reasons, if oceanographic features are affected by the project during the effective period of the proposed regulations, the impact on marine mammal habitat and their prey is likely to be comparatively minor; therefore, we are not predicting take due to habitat and prey impacts, and are not proposing to authorize such take.

Mitigation To Reduce Impacts on All Species

This proposed rulemaking includes a variety of mitigation measures designed to minimize impacts on all marine mammals, with a focus on North Atlantic right whales (the latter is described in more detail below). For impact pile driving of foundation piles, nine overarching mitigation measures are proposed, which are intended to reduce both the number and intensity of marine mammal takes: (1) seasonal/time of day work restrictions; (2) use of multiple PSOs to visually observe for marine mammals (with any detection within specifically designated zones triggering a delay or shutdown); (3) use of PAM to acoustically detect marine mammals, with a focus on detecting baleen whales (with any detection within designated zones triggering delay or shutdown); (4) implementation of clearance zones; (5) implementation of shutdown zones; (6) use of soft-start; (7) use of noise attenuation technology; (8) maintaining situational awareness of marine mammal presence through the requirement that any marine mammal sighting(s) by Atlantic Shores' personnel must be reported to PSOs; (9) sound field verification monitoring; and (10) Vessel Strike Avoidance measures to reduce the risk of a collision with a marine mammal and vessel. For cofferdam installation and removal, we are requiring five overarching mitigation measures: (1) seasonal/time of day work restrictions; (2) use of multiple PSOs to visually observe for marine mammals (with any detection with specifically designated zones that would trigger a delay or shutdown); (3) implementation of clearance zones; (4) implementation of shutdown zones); and (5) maintaining situational awareness of marine mammal presence through the requirement that any marine mammal sighting(s) by Atlantic Shores' personnel must be reported to PSOs. Lastly, for HRG surveys, we are requiring six measures: (1) measures specifically for Vessel Strike Avoidance; (2) specific requirements during daytime and nighttime HRG surveys (3) implementation of clearance zones (4) implementation of shutdown zones; (5) use of ramp-up of acoustic sources; and (6) maintaining situational awareness of marine mammal presence through the requirement that any marine mammal sighting(s) by Atlantic Shores' personnel must be reported to PSOs.

NMFS prescribes mitigation measures based on the following rationale. For activities with large harassment isopleths, Atlantic Shores would be required to reducing the noise levels generated to the lowest levels practicable and would be required to ensure that they do not exceed a noise footprint above that which was modeled, assuming a 10-dB attenuation. Use of a soft-start during impact pile driving will allow animals to move away from ( i.e., avoid) the sound source prior to applying higher hammer energy levels needed to install the pile (Atlantic Shores would not use a hammer energy greater than necessary to install piles). Similarly, ramp-up during HRG surveys would allow animals to move away and avoid the acoustic sources before they reach their maximum energy level. For all activities, clearance zone and shutdown zone implementation, which are required when marine mammals are within given distances associated with certain impact thresholds for all activities, would reduce the magnitude and severity of marine mammal take. Additionally, the use of multiple PSOs (WTG, OSS, and Met Tower foundation installation; temporary cofferdam installation and removal; HRG surveys), PAM (for impact foundation installation), and maintaining awareness of marine mammal sightings reported in the region (WTG, OSS, and Met Tower foundation installation; temporary cofferdam installation and removal; HRG surveys) would aid in detecting marine mammals that would trigger the implementation of the mitigation measures. The reporting requirements, including SFV reporting (for foundation installation and foundation operation), will assist NMFS in identifying if impacts beyond those analyzed in this proposed rule are occurring, potentially leading to the need to enact adaptive management measures in addition to or in the place of the proposed mitigation measures.

Mysticetes

Five mysticete species (comprising five stocks) of cetaceans (North Atlantic right whale, humpback whale, fin whale, sei whale, and minke whale) may be taken by harassment. These species, to varying extents, utilize the specified geographic region, including the Project Area, for the purposes of migration, foraging, and socializing. Mysticetes are in the low-frequency hearing group.

Behavioral data on mysticete reactions to pile-driving noise are scant. Kraus et al. (2019) predicted that the three main impacts of offshore wind farms on marine mammals would consist of displacement, behavioral disruptions, and stress. Broadly, we can look to studies that have focused on other noise sources such as seismic surveys and military training exercises, which suggest that exposure to loud signals can result in avoidance of the sound source (or displacement if the activity continues for a longer duration in a place where individuals would otherwise have been staying, which is less likely for mysticetes in this area), disruption of foraging activities (if they are occurring in the area), local masking around the source, associated stress responses, and impacts to prey, as well as TTS or PTS in some cases.

Mysticetes encountered in the Project Area are expected to primarily be migrating and, to a lesser degree, may be engaged in foraging behavior. The extent to which an animal engages in these behaviors in the area is species-specific and varies seasonally. Many mysticetes are expected to predominantly be migrating through the Project Area towards or from feeding grounds located further north ( e.g., southern New England region, Gulf of Maine, Canada). While we acknowledged above that mortality, hearing impairment, or displacement of mysticete prey species may result locally from impact pile driving, given the very short duration of and broad availability of prey species in the area and the availability of alternative suitable foraging habitat for the mysticete species most likely to be affected, any impacts on mysticete foraging is expected to be minor. Whales temporarily displaced from the Project Area are expected to have sufficient remaining feeding habitat available to them, and would not be prevented from feeding in other areas within the biologically important feeding habitats found further north. In addition, any displacement of whales or interruption of foraging bouts would be expected to be relatively temporary in nature.

The potential for repeated exposures is dependent upon the residency time of whales, with migratory animals unlikely to be exposed on repeated occasions and animals remaining in the area to be more likely exposed repeatedly. For mysticetes, where relatively low amounts of species-specific take by Level B harassment are predicted (compared to the abundance of each mysticete species or stock, such as is indicated in Table 25) and movement patterns suggest that individuals would not necessarily linger in a particular area for multiple days, each predicted take likely represents an exposure of a different individual; the behavioral impacts would, therefore, be expected to occur within a single day within a year—an amount that would clearly not be expected to impact reproduction or survival. Species with longer residence time in the Project Area may be subject to repeated exposures across multiple days.

In general, for this project, the duration of exposures would not be continuous throughout any given day, and pile driving would not occur on all consecutive days within a given year due to weather delays or any number of logistical constraints Atlantic Shores has identified. Species-specific analysis regarding potential for repeated exposures and impacts is provided below.

Fin, humpback, minke, and sei whales are the only mysticete species for which PTS is anticipated and proposed to be authorized. As described previously, PTS for mysticetes from some project activities may overlap frequencies used for communication, navigation, or detecting prey. However, given the nature and duration of the activity, the mitigation measures, and likely avoidance behavior, any PTS is expected to be of a small degree, would be limited to frequencies where pile-driving noise is concentrated ( i.e., only a small subset of their expected hearing range) and would not be expected to impact reproductive success or survival.

North Atlantic Right Whale

North Atlantic right whales are listed as endangered under the ESA and as both depleted and strategic stocks under the MMPA. As described in the Potential Effects of the Specified Activities on Marine Mammals and Their Habitat section, North Atlantic right whales are threatened by a low population abundance, higher than average mortality rates, and lower than average reproductive rates. Recent studies have reported individuals showing high stress levels ( e.g., Corkeron et al., 2017) and poor health, which has further implications on reproductive success and calf survival (Christiansen et al., 2020; Stewart et al., 2021; Stewart et al., 2022). As described below, a UME has been designated for North Atlantic right whales. Given this, the status of the North Atlantic right whale population is of heightened concern and, therefore, merits additional analysis and consideration. No injury or mortality is anticipated or proposed for authorization for this species.

For North Atlantic right whales, this proposed rule would allow for the authorization of up to 21 takes, by Level B harassment only, over the 5-year period, with a maximum annual allowable take by Level B harassment, would be 9 (equating to approximately 2.66 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years where only HRG surveys would be occurring) The Project Area is known as a migratory corridor for North Atlantic right whales and given the nature of migratory behavior ( e.g., continuous path), as well as the low number of total takes, we anticipate that few, if any, of the instances of take would represent repeat takes of any individual, though it could occur if whales are engaged in opportunistic foraging behavior. Whitt et al. (2013) observed two juveniles potentially skim-feeding off the coast of Barnegat Bay, New Jersey in January. While opportunistic foraging may occur in the Project area, the habitat does not support prime foraging habitat.

The highest density of North Atlantic right whales in the Project Area occurs in the winter (Table 9). The Mid-Atlantic, including the Project Area, may be a stopover site for migrating North Atlantic right whales moving to or from southeastern calving grounds. Migrating North Atlantic right whales have been acoustically detected north of the Project Area in the New York Bight from February to May and August through December (Biedron et al., 2009). Similarly, the waters off the coast of New Jersey, including those surrounding the Project Area in the New Jersey Wind Energy Area (NJ WEA), have documented North Atlantic right whale presence as the area is an important migratory route for the species to the northern feeding areas near the Gulf of Maine and Georges Banks and to their southern breeding and calving grounds off the southeastern U.S. (CETAP, 1982; Knowlton and Kraus, 2001; Knowlton et al., 2022; Biedron et al., 2009; DoC, 2016b). However, comparatively, the Project Area is not known as an important area for feeding, breeding, or calving.

North Atlantic right whales range outside the Project Area for their main feeding, breeding, and calving activities (Geo-Marine, 2010). Additional qualitative observations include animals feeding and socializing in New England waters, north of the NJ WEA (Quintana-Rizzo et al., 2021). The North Atlantic right whales observed during the study period, north of the NJ WEA, were primarily concentrated in the northeastern and southeastern sections of the Massachusetts WEA (MA WEA) during the summer (June–August) and winter (December–February). North Atlantic right whale distribution did shift to the west into the Rhode Island/Massachusetts (RI/MA WEA) in the spring (March–May). Quintana-Rizzo et al. (2021) found that approximately 23 percent of the right whale population is present from December through May, and the mean residence time has tripled to an average of 13 days during these months. The NJ WEA is not in or near these areas important to feeding, breeding, and calving activities.

In general, North Atlantic right whales in the Project Area are expected to be engaging in migratory behavior. Given the species' migratory behavior in the Project Area, we anticipate individual whales would be typically migrating through the area during most months when foundation installation would occur (given the seasonal restrictions on foundation installation, rather than lingering for extended periods of time). Other work that involves either much smaller harassment zones ( e.g., HRG surveys) or is limited in amount ( e.g., cable landfall construction) may also occur during periods when North Atlantic right whales are using the habitat for migration. It is important to note the activities occurring from December through May that may impact North Atlantic right whale would be primarily HRG surveys and the nearshore cofferdam installation and removal, which would not result in very high received levels. Across all years, if an individual were to be exposed during a subsequent year, the impact of that exposure is likely independent of the previous exposure given the duration between exposures.

As described in the Description of Marine Mammals in the Geographic Area of Specified Activities, North Atlantic right whales are presently experiencing an ongoing UME (beginning in June 2017). Preliminary findings support human interactions, specifically vessel strikes and entanglements, as the cause of death for the majority of North Atlantic right whales. Given the current status of the North Atlantic right whale, the loss of even one individual could significantly impact the population. No mortality, serious injury, or injury of North Atlantic right whales as a result of the project is expected or proposed to be authorized. Any disturbance to North Atlantic right whales due to Atlantic Shores' activities is expected to result in temporary avoidance of the immediate area of construction. As no injury, serious injury, or mortality is expected or authorized, and Level B harassment of North Atlantic right whales will be reduced to the level of least practicable adverse impact through use of mitigation measures, the authorized number of takes of North Atlantic right whales would not exacerbate or compound the effects of the ongoing UME.

As described in the general Mysticetes section above, foundation installation is likely to result in the highest amount of annual take and is of greatest concern given loud source levels. This activity would likely be limited to up to 225 days (201 for WTG/Met Tower monopile/jacket foundations and 24 for OSS jacket foundations) over a maximum of 2 years, during times when, based on the best available scientific data, North Atlantic right whales are less frequently encountered due to their migratory behavior. The potential types, severity, and magnitude of impacts are also anticipated to mirror that described in the general Mysticetes section above, including avoidance (the most likely outcome), changes in foraging or vocalization behavior, masking, a small amount of TTS, and temporary physiological impacts ( e.g., change in respiration, change in heart rate). Importantly, the effects of the proposed activities are expected to be sufficiently low-level and localized to specific areas as to not meaningfully impact important behaviors, such as migratory behavior of North Atlantic right whales. These takes are expected to result in temporary behavioral reactions, such as slight displacement (but not abandonment) of migratory habitat or temporary cessation of feeding. Further, given these exposures are generally expected to occur to different individual right whales migrating through ( i.e., many individuals would not be impacted on more than 1 day in a year), with some subset potentially being exposed on no more than a few days within the year, they are unlikely to result in energetic consequences that could affect reproduction or survival of any individuals.

Overall, NMFS expects that any behavioral harassment of North Atlantic right whales incidental to the specified activities would not result in changes to their migration patterns or foraging success, as only temporary avoidance of an area during construction is expected to occur. As described previously, North Atlantic right whales migrating through the Project Area are not expected to remain in this habitat for extensive durations, and any temporarily displaced animals would be able to return to or continue to travel through and forage in these areas once activities have ceased.

Although acoustic masking may occur in the vicinity of the foundation installation activities, based on the acoustic characteristics of noise associated with pile driving ( e.g., frequency spectra, short duration of exposure) and construction surveys ( e.g., intermittent signals), NMFS expects masking effects to be minimal ( e.g., impact pile driving) to none ( e.g., HRG surveys). In addition, masking would likely only occur during the period of time that a North Atlantic right whale is in the relatively close vicinity of pile driving, which is expected to be intermittent within a day, and confined to the months in which North Atlantic right whales are at lower densities and primarily moving through the area, anticipated mitigation effectiveness, and likely avoidance behaviors. TTS is another potential form of Level B harassment that could result in brief periods of slightly reduced hearing sensitivity affecting behavioral patterns by making it more difficult to hear or interpret acoustic cues within the frequency range (and slightly above) of sound produced during impact pile driving. However, any TTS would likely be of low amount, limited duration, and limited to frequencies where most construction noise is centered (below 2 kHz). NMFS expects that right whale hearing sensitivity would return to pre-exposure levels shortly after migrating through the area or moving away from the sound source.

As described in the Potential Effects of Specified Activities on Marine Mammals and Their Habitat section, the distance of the receiver to the source influences the severity of response with greater distances typically eliciting less severe responses. NMFS recognizes North Atlantic right whales migrating could be pregnant females (in the fall) and cows with older calves (in spring) and that these animals may slightly alter their migration course in response to any foundation pile-driving; however, as described in the Potential Effects of Specified Activities on Marine Mammals and Their Habitat section, we anticipate that course diversion would be of small magnitude. Hence, while some avoidance of the pile driving activities may occur, we anticipate any avoidance behavior of migratory North Atlantic right whales would be similar to that of gray whales (Tyack et al., 1983), on the order of hundreds of meters up to 1 to 2 km. This diversion from a migratory path otherwise uninterrupted by the proposed activities is not expected to result in meaningful energetic costs that would impact annual rates of recruitment of survival. NMFS expects that North Atlantic right whales would be able to avoid areas during periods of active noise production while not being forced out of this portion of their habitat.

North Atlantic right whale presence in the Project Area is year-round. However, abundance during summer months is lower compared to the winter months with spring and fall serving as “shoulder seasons” wherein abundance waxes (fall) or wanes (spring). Given this year-round habitat usage, in recognition that where and when whales may actually occur during project activities is unknown as it depends on the annual migratory behaviors, Atlantic Shores has proposed and NMFS is proposing to require a suite of mitigation measures designed to reduce impacts to North Atlantic right whales to the maximum extent practicable. These mitigation measures ( e.g., seasonal/daily work restrictions, vessel separation distances, reduced vessel speed) would not only avoid the likelihood of vessel strikes but also would minimize the severity of behavioral disruptions by minimizing impacts ( e.g., through sound reduction using attenuation systems and reduced temporal overlap of project activities and North Atlantic right whales). This would further ensure that the number of takes by Level B harassment that are estimated to occur are not expected to affect reproductive success or survivorship by detrimental impacts to energy intake or cow/calf interactions during migratory transit. However, even in consideration of recent habitat-use and distribution shifts, Atlantic Shores would still be installing foundations when the presence of North Atlantic right whales is expected to be lower.

As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, Atlantic Shores would be constructed within the North Atlantic right whale migratory corridor BIA, which represent areas and months within which a substantial portion of a species or population is known to migrate. The Lease Area is extremely small compared with the migratory BIA area (approximately 413 km² for OCS–A 0499 versus the size of the full North Atlantic right whale migratory BIA, 269,448 km² ). Because of this, the overall North Atlantic right whale migration is not expected to be impacted by the proposed activities. There are no known North Atlantic right whale feeding, breeding, or calving areas within the Project Area. Prey species are mobile ( e.g., calanoid copepods can initiate rapid and directed escape responses) and are broadly distributed throughout the Project Area (noting again that North Atlantic right whale prey is not particularly concentrated in the Project Area relative to nearby habitats). Therefore, any impacts to prey that may occur are also unlikely to impact marine mammals.

The most significant measure to minimize impacts to individual North Atlantic right whales is the seasonal moratorium on all foundation installation activities from January 1 through April 30, and the limitation on these activities occurring in December ( e.g., only work with approval from NMFS), when North Atlantic right whale abundance in the Project Area is expected to be highest. NMFS also expects this measure to greatly reduce the potential for mother-calf pairs to be exposed to impact pile driving noise above the Level B harassment threshold during their annual spring migration through the Project Area from calving grounds to primary foraging grounds ( e.g., Cape Cod Bay). NMFS expects that exposures to North Atlantic right whales would be reduced due to the additional proposed mitigation measures that would ensure that any exposures above the Level B harassment threshold would result in only short-term effects to individuals exposed.

Pile driving may only begin in the absence of North Atlantic right whales (based on visual and passive acoustic monitoring). If pile driving has commenced, NMFS anticipates North Atlantic right whales would avoid the area, utilizing nearby waters to carry on pre-exposure behaviors. However, foundation installation activities must be shut down if a North Atlantic right whale is sighted at any distance unless a shutdown is not feasible due to risk of injury or loss of life. Shutdown may occur anywhere if North Atlantic right whales are seen within or beyond the Level B harassment zone, further minimizing the duration and intensity of exposure. NMFS anticipates that if North Atlantic right whales go undetected and they are exposed to foundation installation noise, it is unlikely a North Atlantic right whale would approach the sound source locations to the degree that they would purposely expose themselves to very high noise levels. This is because typical observed whale behavior demonstrates likely avoidance of harassing levels of sound where possible (Richardson et al., 1985). These measures are designed to avoid PTS and also reduce the severity of Level B harassment, including the potential for TTS. While some TTS could occur, given the proposed mitigation measures ( e.g., delay pile driving upon a sighting or acoustic detection and shutting down upon a sighting or acoustic detection), the potential for TTS to occur is low.

The proposed clearance and shutdown measures are most effective when detection efficiency is maximized, as the measures are triggered by a sighting or acoustic detection. To maximize detection efficiency, Atlantic Shores proposed, and NMFS is proposing to require, the combination of PAM and visual observers. NMFS is proposing to require communication protocols with other project vessels, and other heightened awareness efforts ( e.g., daily monitoring of North Atlantic right whale sighting databases) such that as a North Atlantic right whale approaches the source (and thereby could be exposed to higher noise energy levels), PSO detection efficacy would increase, the whale would be detected, and a delay to commencing foundation installation or shutdown (if feasible) would occur. In addition, the implementation of a soft-start for impact pile driving would provide an opportunity for whales to move away from the source if they are undetected, reducing received levels.

For HRG surveys, the maximum distance to the Level B harassment threshold is 141 m. The estimated take, by Level B harassment only, associated with HRG surveys is to account for any North Atlantic right whale sightings PSOs may miss when HRG acoustic sources are active. However, because of the short maximum distance to the Level B harassment threshold, the requirement that vessels maintain a distance of 500 m from any North Atlantic right whales, the fact that whales are unlikely to remain in close proximity to an HRG survey vessel for any length of time, and that the acoustic source would be shut down if a North Atlantic right whale is observed within 500 m of the source, any exposure to noise levels above the harassment threshold (if any) would be very brief. To further minimize exposures, ramp-up of sub-bottom profilers must be delayed during the clearance period if PSOs detect a North Atlantic right whale (or any other ESA-listed species) within 500 m of the acoustic source. With implementation of the proposed mitigation requirements, take by Level A harassment is unlikely and, therefore, not proposed for authorization. Potential impacts associated with Level B harassment would include low-level, temporary behavioral modifications, most likely in the form of avoidance behavior. Given the high level of precautions taken to minimize both the amount and intensity of Level B harassment on North Atlantic right whales, it is unlikely that the anticipated low-level exposures would lead to reduced reproductive success or survival.

As described above, no serious injury or mortality, or Level A harassment, of North Atlantic right whale is anticipated or proposed for authorization. Extensive North Atlantic right whale-specific mitigation measures (beyond the robust suite required for all species) are expected to further minimize the amount and severity of Level B harassment. Given the documented habitat use within the area, the majority of the individuals predicted to be taken (including no more than 21 instances of take, by Level B harassment only, over the course of the 5-year rule, with an annual maximum of no more than 9) would be impacted on only 1, or maybe 2, days in a year as North Atlantic right whales utilize this area for migration and would be transiting rather than residing in the area for extended periods of time; and, further, any impacts to North Atlantic right whales are expected to be in the form of lower-level behavioral disturbance.

Given the magnitude and severity of the impacts discussed above, and in consideration of the proposed mitigation and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take (by Level B harassment only) anticipated and proposed for authorization would have a negligible impact on the North Atlantic right whale.

Fin Whale

The fin whale is listed as Endangered under the ESA, and the western North Atlantic stock is considered both Depleted and Strategic under the MMPA. No UME has been designated for this species or stock. No serious injury or mortality is anticipated or proposed for authorization for this species.

The proposed rule would allow for the authorization of up to 43 takes, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take by Level A harassment and Level B harassment, would be 4 and 16, respectively (combined, this annual take (n=20) equates to approximately 0.29 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). The Project Area does not overlap any known areas of specific biological importance to fin whales. It is likely that some subset of the individual whales exposed could be taken several times annually.

Level B harassment is expected to be in the form of behavioral disturbance, primarily resulting in avoidance of the Project Area where foundation installation is occurring, and some low-level TTS and masking that may limit the detection of acoustic cues for relatively brief periods of time. Any potential PTS would be minor (limited to a few dB) and any TTS would be of short duration and concentrated at half or one octave above the frequency band of pile-driving noise (most sound is below 2 kHz) which does not include the full predicted hearing range of fin whales.

Fin whales are present in the waters off of New Jersey year round and are one of the most frequently observed large whales and cetaceans in continental shelf waters, principally from Cape Hatteras in the Mid-Atlantic northward to Nova Scotia, Canada (Sergeant, 1977; Sutcliffe and Brodie, 1977; CETAP, 1982; Hain et al., 1992; Geo-Marine, 2010; BOEM 2012; Edwards et al., 2015; Hayes et al., 2022). Fin whales have high relative abundance in the Mid-Atlantic and Project Area, most observations occur in the winter and summer months (Geo-Marine, 2010; Hayes et al., 2022) though detections do occur in spring and fall (Watkins et al., 1987; Clark and Gagnon 2002; Geo-Marine, 2010; Morano et al., 2012). However, fin whales typically feed in waters off of New England and within the Gulf of Maine, areas north of the Project Area, as New England and Gulf of St. Lawrence waters represent major feeding ground for fin whales (Hayes et al., 2022). Hain et al. (1992), based on an analysis of neonate stranding data, suggested that calving takes place during October to January in latitudes of the U.S. mid-Atlantic region; however, it is unknown where calving, mating, and wintering occur for most of the population (Hayes et al., 2022).

Given the documented habitat use within the area, some of the individuals taken would likely be exposed on multiple days. However, as described, the project area does not include areas where fin whales are known to concentrate for feeding or reproductive behaviors and the predicted takes are expected to be in the form of lower-level impacts. Given the magnitude and severity of the impacts discussed above (including no more than 43 takes, by Level A harassment and Level B harassment, over the course of the 5-year rule, and a maximum annual allowable take by Level A harassment and Level B harassment, of 4 and 16, respectively), and in consideration of the proposed mitigation and other information presented, Atlantic Shores' proposed activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take (by Level A harassment and Level B harassment) anticipated and proposed to be authorized would have a negligible impact on the western North Atlantic stock of fin whales.

Humpback Whale

The West Indies DPS of humpback whales is not listed as threatened or endangered under the ESA, but the Gulf of Maine stock, which includes individuals from the West Indies DPS, is considered Strategic under the MMPA. However, as described in the Description of Marine Mammals in the Geographic Area of Specified Activities, humpback whales along the Atlantic Coast have been experiencing an active UME as elevated humpback whale mortalities have occurred along the Atlantic coast from Maine through Florida since January 2016. Of the cases examined, approximately 40 percent had evidence of human interaction (vessel strike or entanglement). The UME does not yet provide cause for concern regarding population-level impacts and take from vessel strike and entanglement is not proposed to be authorized. Despite the UME, the relevant population of humpback whales (the West Indies breeding population, or DPS of which the Gulf of Maine stock is a part) remains stable at approximately 12,000 individuals.

The proposed rule would allow for the authorization of up to 38 takes, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take by Level A harassment and Level B harassment, would be 4 and 15, respectively (combined, this maximum annual take (n=19) equates to approximately 1.36 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). Given that humpback whales are known to forage off of New Jersey, it is likely that some subset of the individual whales exposed could be taken several times annually.

Among the activities analyzed, impact pile driving is likely to result in the highest amount of Level A harassment annual take of (n=4) humpback whales. The maximum amount of annual take proposed to be authorized (n=15), by Level B harassment, is highest for impact pile driving.

As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, Humpback whales are known to occur regularly throughout the Mid-Atlantic Bight, including New Jersey waters, with strong seasonality where peak occurrences occur April to June (Barco et al., 2002; Geo-Marine, 2010; Curtice et al., 2019; Hayes et al., 2022).

In the western North Atlantic, humpback whales feed during spring, summer, and fall over a geographic range encompassing the eastern coast of the U.S. Feeding is generally considered to be focused in areas north of the project area, including a feeding BIA in the Gulf of Maine/Stellwagen Bank/Great South Channel, but has been documented farther south and off the coast of New Jersey. When foraging, humpback whales tend to remain in the area for extended durations to capitalize on the food sources.

Assuming humpback whales who are feeding in waters within or surrounding the Project Area behave similarly, we expect that the predicted instances of disturbance could be comprised of some individuals that may be exposed on multiple days if they are utilizing the area as foraging habitat. Also similar to other baleen whales, if migrating, such that individuals would likely be exposed to noise levels from the project above the harassment thresholds only once during migration through the Project Area.

For all the reasons described in the Mysticetes section above, we anticipate any potential PTS and TTS would be concentrated at half or one octave above the frequency band of pile-driving noise (most sound is below 2 kHz) which does not include the full predicted hearing range of baleen whales. If TTS is incurred, hearing sensitivity would likely return to pre-exposure levels relatively shortly after exposure ends. Any masking or physiological responses would also be of low magnitude and severity for reasons described above.

Given the magnitude and severity of the impacts discussed above (including no more than 38 takes over the course of the 5-year rule, and a maximum annual allowable take by Level A harassment and Level B harassment, of 4 and 15, respectively), and in consideration of the proposed mitigation measures and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed to be authorized would have a negligible impact on the Gulf of Maine stock of humpback whales.

Minke Whale

Minke whales are not listed under the ESA, and the Canadian East Coast stock is neither considered Depleted nor strategic under the MMPA. There are no known areas of specific biological importance in or adjacent to the Project Area. As described in the Description of Marine Mammals in the Geographic Area of Specified Activities, a UME has been designated for this species but is pending closure. No serious injury or mortality is anticipated or proposed for authorization for this species.

The proposed rule would allow for the authorization of up to 347 takes, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take by Level A harassment and Level B harassment, would be 17 and 159, respectively (combined, this annual take (n=176) equates to approximately 0.80 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, minke whales are common offshore the U.S. Eastern Seaboard with a strong seasonal component in the continental shelf and in deeper, off-shelf waters (CETAP, 1982; Hayes et al., 2022). In the project area, minke whales are predominantly migratory and their known feeding areas are north, including a feeding BIA in the southwestern Gulf of Maine and George's Bank. Therefore, they would be more likely to be moving through (with each take representing a separate individual), though it is possible that some subset of the individual whales exposed could be taken up to a few times annually.

As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, there is a UME for minke whales along the Atlantic Coast from Maine through South Carolina, with the highest number of deaths in Massachusetts, Maine, and New York, and preliminary findings in several of the whales have shown evidence of human interactions or infectious diseases. However, we note that the population abundance is greater than 21,000 and the take proposed for authorization through this action is not expected to exacerbate the UME in any way.

We anticipate the impacts of this harassment to follow those described in the general Mysticetes section above. Any potential PTS would be minor (limited to a few dB) and any TTS would be of short duration and concentrated at half or one octave above the frequency band of pile-driving noise (most sound is below 2 kHz) which does not include the full predicted hearing range of minke whales. Level B harassment would be temporary, with primary impacts being temporary displacement of the Project Area but not abandonment of any migratory or foraging behavior.

Given the magnitude and severity of the impacts discussed above (including no more than 347 takes over the course of the 5-year rule, and a maximum annual allowable take by Level A harassment and Level B harassment, of 17 and 159, respectively), and in consideration of the proposed mitigation measures and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed to be authorized would have a negligible impact on the Canadian Eastern Coastal stock of minke whales.

Sei Whale

Sei whales are listed as Endangered under the ESA, and the Nova Scotia stock is considered both Depleted and Strategic under the MMPA. There are no known areas of specific biological importance in or adjacent to the Project Area and no UME has been designated for this species or stock. No serious injury or mortality is anticipated or proposed for authorization for this species.

The proposed rule would allow for the authorization of up to 24 takes, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take by Level A harassment and Level B harassment, would be 1 and 8, respectively (combined, this annual take (n=9) equates to approximately 0.14 percent of the stock abundance, if each take were considered to be of a different individual). As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, most of the sei whale distribution is concentrated in Canadian waters and seasonally in northerly U.S. waters, though they are uncommonly observed in the waters off of New Jersey Because sei whales are migratory and their known feeding areas are east and north of the Project Area ( e.g., there is a feeding BIA in the Gulf of Maine), they would be more likely to be moving through and, considering this and the very low number of total takes, it is unlikely that any individual would be exposed more than once within a given year.

With respect to the severity of those individual takes by behavioral Level B harassment, we would anticipate impacts to be limited to low-level, temporary behavioral responses with avoidance and potential masking impacts in the vicinity of the turbine installation to be the most likely type of response. Any potential PTS and TTS would likely be concentrated at half or one octave above the frequency band of pile-driving noise (most sound is below 2 kHz) which does not include the full predicted hearing range of sei whales. Moreover, any TTS would be of a small degree. Any avoidance of the Project Area due to the Project's activities would be expected to be temporary.

Given the magnitude and severity of the impacts discussed above (including no more than 24 takes over the course of the 5-year rule, and a maximum annual allowable take by Level A harassment and Level B harassment, of 1 and 8, respectively), and in consideration of the proposed mitigation measures and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed to be authorized would have a negligible impact on the Nova Scotia stock of sei whales.

Odontocetes

In this section, we include information here that applies to all of the odontocete species and stocks addressed below. Odontocetes include dolphins, porpoises, and all other whales possessing teeth, and we further divide them into the following subsections: sperm whales, small whales and dolphins, and harbor porpoise. These sub-sections include more specific information, as well as conclusions for each stock represented.

All of the takes of odontocetes proposed for authorization incidental to Atlantic Shores' specified activities are by pile driving and HRG surveys. No serious injury or mortality is anticipated or proposed. We anticipate that, given ranges of individuals ( i.e., that some individuals remain within a small area for some period of time), and non-migratory nature of some odontocetes in general (especially as compared to mysticetes), these takes are more likely to represent multiple exposures of a smaller number of individuals than is the case for mysticetes, though some takes may also represent one-time exposures to an individual. Foundation installation is likely to disturb odontocetes to the greatest extent, compared to HRG surveys. While we expect animals to avoid the area during foundation installation, their habitat range is extensive compared to the area ensonified during these activities.

As described earlier, Level B harassment may include direct disruptions in behavioral patterns ( e.g., avoidance, changes in vocalizations (from masking) or foraging), as well as those associated with stress responses or TTS. Odontocetes are highly mobile species and, similar to mysticetes, NMFS expects any avoidance behavior to be limited to the area near the sound source. While masking could occur during foundation installation, it would only occur in the vicinity of and during the duration of the activity, and would not generally occur in a frequency range that overlaps most odontocete communication or any echolocation signals. The mitigation measures ( e.g., use of sound attenuation systems, implementation of clearance and shutdown zones) would also minimize received levels such that the severity of any behavioral response would be expected to be less than exposure to unmitigated noise exposure.

Any masking or TTS effects are anticipated to be of low-severity. First, the frequency range of pile driving, the most impactful activity proposed to be conducted in terms of response severity, falls within a portion of the frequency range of most odontocete vocalizations. However, odontocete vocalizations span a much wider range than the low frequency construction activities proposed for the project. As described above, recent studies suggest odontocetes have a mechanism to self-mitigate ( i.e., reduce hearing sensitivity) the impacts of noise exposure, which could potentially reduce TTS impacts. Any masking or TTS is anticipated to be limited and would typically only interfere with communication within a portion of an odontocete's range and as discussed earlier, the effects would only be expected to be of a short duration and, for TTS, a relatively small degree.

Furthermore, odontocete echolocation occurs predominantly at frequencies significantly higher than low frequency construction activities. Therefore, there is little likelihood that threshold shift would interfere with feeding behaviors. For HRG surveys, the sources operate at higher frequencies than foundation installation activities. However, sounds from these sources attenuate very quickly in the water column, as described above. Therefore, any potential for PTS and TTS and masking is very limited. Further, odontocetes ( e.g., common dolphins, spotted dolphfins, bottlenose dolphins) have demonstrated an affinity to bow-ride actively surveying HRG surveys. Therefore, the severity of any harassment, if it does occur, is anticipated to be discountable based on the lack of avoidance previously demonstrated by these species.

The waters off the coast of New Jersey are used by several odontocete species. However, none except the sperm whale are listed under the ESA, and there are no known habitats of particular importance. In general, odontocete habitat ranges are far-reaching along the Atlantic coast of the U.S., and the waters off of New Jersey, including the Project Area, do not contain any particularly unique odontocete habitat features.

Sperm Whales

Sperm whales are listed as endangered under the ESA, and the North Atlantic stock is considered both Depleted and Strategic under the MMPA. The North Atlantic stock spans the East Coast out into oceanic waters well beyond the U.S. EEZ. Although listed as endangered, the primary threat faced by the sperm whale across its range ( i.e., commercial whaling) has been eliminated. Current potential threats to the species globally include vessel strikes, entanglement in fishing gear, anthropogenic noise, exposure to contaminants, climate change, and marine debris. There is no currently reported trend for the stock and, although the species is listed as endangered under the ESA, there are no specific issues with the status of the stock that cause particular concern ( e.g., no UMEs). There are no known areas of biological importance ( e.g., critical habitat or BIAs) in or near the Project Area. No mortality or serious injury is anticipated or proposed to be authorized for this species.

The proposed rule would allow for the authorization of up to 13 takes, by Level B harassment only, over the 5-year period. The maximum annual allowable take would be 5, which equates to approximately 0.11 percent of the stock abundance, if each take were considered to be of a different individual, and with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). Given sperm whale's preference for deeper waters, especially for feeding, it is unlikely that individuals would remain in the Project Area for multiple days, and therefore, the estimated takes likely represent exposures of different individuals on 1 day each, annually.

If sperm whales are present in the Project Area during any project activities, they would likely be only transient visitors and not engaging in any significant behaviors. Further, the potential for TTS is low for reasons described in the general Odontocete section, but, if it does occur, any hearing shift would be small and of a short duration. Because whales are not expected to be foraging in the Project Area, any TTS is not expected to interfere with foraging behavior.

Given the magnitude and severity of the impacts discussed above (including no more than 13 takes, by Level B harassment only, over the course of the 5-year rule, and a maximum annual allowable take of 5), and in consideration of the proposed mitigation and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed to be authorized would have a negligible impact on the North Atlantic stock of sperm whales.

Dolphins and Small Whales (Including Delphinids)

The six species and seven stocks included in this group (which are indicated in Table 4 in the Delphinidae family) are not listed under the ESA; however, short-finned pilot whales are listed as Strategic under the MMPA. There are no known areas of specific biological importance in or around the Project Area for any of these species and no UMEs have been designated for any of these species. No serious injury or mortality is anticipated or proposed for authorization for these species.

The six delphinid species with take proposed for the project consist of: Atlantic spotted dolphin, Atlantic white-sided dolphin, common bottlenose dolphin, common dolphin, long-finned pilot whale, short-finned pilot whale, and Risso's dolphin. The proposed rule would allow for the authorization of up to between 46 and 7,951 takes (depending on species), by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take for these species by Level A harassment and Level B harassment, would range from 0 to 1 and 14 to 3,634, respectively (this annual take equates to approximately 0.05 to 29.36 percent of the stock abundance, depending on each species, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring).

For both stocks of bottlenose dolphins, given the higher number of takes relative to the stock abundance, primarily due to nearshore landfall activities ( i.e., temporary cofferdam installation and removal), while some of the takes likely represent exposures of different individuals on 1 day a year, it is likely that some subset of the individuals exposed could be taken several times annually. For Atlantic spotted dolphins, Atlantic white-sided dolphins, common dolphins, long- and short-finned pilot whales, and Risso's dolphins, given the number of takes, while many of the takes likely represent exposures of different individuals on 1 day a year, some subset of the individuals exposed could be taken up to a few times annually.

The number of takes, likely movement patterns of the affected species, and the intensity of any Level A or B harassments, combined with the availability of alternate nearby foraging habitat suggests that the likely impacts would not impact the reproduction or survival of any individuals. While delphinids may be taken on several occasions, none of these species are known to have small home ranges within the Project Area or known to be particularly sensitive to anthropogenic noise. The potential for PTS in dolphins and small whales is very low and, if PTS does occur, would occur to a limited number of individuals, only affect a small portion of the individual's hearing range, and would be limited to the frequency ranges of the activity which does not span across most of their hearing range. Some TTS can also occur but, again, it would be limited to the frequency ranges of the activity and any loss of hearing sensitivity is anticipated to return to pre-exposure conditions shortly after the animals move away from the source or the source ceases.

Given the magnitude and severity of the impacts discussed above, and in consideration of the proposed mitigation and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed for authorization would have a negligible impact on all of the species and stocks addressed in this section.

Harbor Porpoises

Harbor porpoises are not listed as Threatened or Endangered under the ESA, and the Gulf of Maine/Bay of Fundy stock is neither considered depleted or strategic under the MMPA. The stock is found predominantly in northern U.S. coastal waters (less than 150 m depth) and up into Canada's Bay of Fundy (between New Brunswick and Nova Scotia). Although the population trend is not known, there are no UMEs or other factors that cause particular concern for this stock. No mortality or non-auditory injury are anticipated or proposed for authorization for this stock.

The proposed rule would allow for the authorization of up to 335 takes, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take by Level A harassment and Level B harassment, would be 13 and 173, respectively (combined, this annual take (n=186) equates to approximately 0.19 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). Given the number of takes, while many of the takes likely represent exposures of different individuals on 1 day a year, some subset of the individuals exposed could be taken up to a few times annually.

Regarding the severity of takes by Level B harassment, because harbor porpoises are particularly sensitive to noise, it is likely that a fair number of the responses could be of a moderate nature, particularly to pile driving. In response to pile driving, harbor porpoises are likely to avoid the area during construction, as previously demonstrated in Tougaard et al. (2009) in Denmark, in Dahne et al. (2013) in Germany, and in Vallejo et al. (2017) in the United Kingdom, although a study by Graham et al. (2019) may indicate that the avoidance distance could decrease over time. Given that foundation installation is scheduled to occur off the coast of New Jersey and, given alternative foraging areas nearby, any avoidance of the area by individuals is not likely to impact the reproduction or survival of any individuals.

With respect to PTS and TTS, the effects on an individual are likely relatively low given the frequency bands of pile driving (most energy below 2 kHz) compared to harbor porpoise hearing (150 Hz to 160 kHz peaking around 40 kHz). Specifically, TTS is unlikely to impact hearing ability in their more sensitive hearing ranges, or the frequencies in which they communicate and echolocate. We expect any PTS that may occur to be within the very low end of their hearing range where harbor porpoises are not particularly sensitive and any PTS would affect a relatively small portion of the individual's hearing range. As such, any PTS would not interfere with key foraging or reproductive strategies necessary for reproduction or survival.

As discussed in Hayes et al. (2022), harbor porpoises are seasonally distributed. During fall (October through December) and spring (April through June), harbor porpoises are widely dispersed from New Jersey to Maine, with lower densities farther north and south. During winter (January to March), intermediate densities of harbor porpoises can be found in waters off New Jersey to North Carolina, and lower densities are found in waters off New York to New Brunswick, Canada. In non-summer months they have been seen from the coastline to deep waters (>1,800 m; Westgate et al., 1998), although the majority are found over the continental shelf. While harbor porpoises are likely to avoid the area during any of the project's construction activities, as demonstrated during European wind farm construction, the time of year in which work would occur is when harbor porpoises are not in highest abundance, and any work that does occur would not result in the species' abandonment of the waters off of New Jersey.

Given the magnitude and severity of the impacts discussed above, and in consideration of the proposed mitigation and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed for authorization would have a negligible impact on the Gulf of Maine/Bay of Fundy stock of harbor porpoises.

Phocids (Harbor Seals and Gray Seals)

The harbor seal and gray seal are not listed under the ESA, and neither the western North Atlantic stock of gray seal nor the western North Atlantic stock of harbor seal are considered depleted or strategic under the MMPA. There are no known areas of specific biological importance in or around the Project Area. As described in the Description of Marine Mammals in the Geographic Area of Specified Activities section, a UME has been designated for harbor seals and gray seals and is described further below. No serious injury or mortality is anticipated or proposed for authorization for this species.

For the two seal species, the proposed rule would allow for the total authorization of up to 675 (gray seal) and 1,526 (harbor seal) takes for each species, by Level A harassment and Level B harassment, over the 5-year period. The maximum annual allowable take for these species, by Level A harassment and Level B harassment, would range from 2 to 8 and 299 to 684, respectively (combined, this annual take (n=301 to 692) equates to approximately 1.10 to 1.13 percent of the stock abundance, if each take were considered to be of a different individual), with far lower numbers than that expected in the years without foundation installation ( e.g., years when only HRG surveys would be occurring). Though gray seals and harbor seals are considered migratory and no specific feeding areas have been designated in the area, the higher number of takes relative to the stock abundance suggests that while some of the takes likely represent exposures of different individuals on 1 day a year, it is likely that some subset of the individuals exposed could be taken several times annually.

Harbor and gray seals occur in New Jersey waters most often from December through April, with harbor seal occurrences more common than gray seals (Reynolds, 2021). Seals are more likely to be close to shore ( e.g., closer to the edge of the area ensonified above NMFS' harassment threshold), such that exposure to foundation installation would be expected to be at comparatively lower levels. Known haul-outs for seals occur near the coastal cofferdam locations at the Atlantic landfall site and the Monmouth landfall site ( i.e., in Sandy Hook, Barnegat Bay, and Great Bay). However, based on the distances between the cofferdam locations and the known haul-out sites, neither Atlantic Shores, nor NMFS, expects that in-air sounds produced would cause the take of hauled out pinnipeds. As all documented pinniped haul-outs are located far from each of the cofferdam locations, NMFS does not expect any harassment to occur, nor have we proposed to authorize any take from in-air impacts on hauled out seals.

As described in the Potential Effects of Specified Activities on Marine Mammals and Their Habitat section, construction of wind farms in Europe resulted in pinnipeds temporarily avoiding construction areas but returning within short time frames after construction was complete (Carroll et al., 2010; Hamre et al., 2011; Hastie et al., 2015; Russell et al., 2016; Brasseur et al., 2010). Effects on pinnipeds that are taken by Level B harassment in the Project Area would likely be limited to reactions such as increased swimming speeds, increased surfacing time, or decreased foraging (if such activity were occurring). Most likely, individuals would simply move away from the sound source and be temporarily displaced from those areas (Lucke et al., 2006; Edren et al., 2010; Skeate et al., 2012; Russell et al., 2016). Given the low anticipated magnitude of impacts from any given exposure ( e.g., temporary avoidance), even repeated Level B harassment across a few days of some small subset of individuals, which could occur, is unlikely to result in impacts on the reproduction or survival of any individuals. Moreover, pinnipeds would benefit from the mitigation measures described in 50 CFR part 217—Regulations Governing the Taking and Importing of Marine Mammals Incidental to Specified Activities.

As described above, noise from pile driving is mainly low frequency and, while any PTS and TTS that does occur would fall within the lower end of pinniped hearing ranges (50 Hz to 86 kHz), PTS and TTS would not occur at frequencies around 5 kHz, where pinniped hearing is most susceptible to noise-induced hearing loss (Kastelein et al., 2018). In summary, any PTS and TTS would be of small degree and not occur across the entire, or even most sensitive, hearing range. Hence, any impacts from PTS and TTS are likely to be of low severity and not interfere with behaviors critical to reproduction or survival.

Elevated numbers of harbor seal and gray seal mortalities were first observed in July 2018 and occurred across Maine, New Hampshire, and Massachusetts until 2020. Based on tests conducted so far, the main pathogen found in the seals belonging to that UME was phocine distemper virus, although additional testing to identify other factors that may be involved in this UME are underway. Currently, the only active UME is occurring in Maine with some harbor and gray seals testing positive for highly pathogenic avian influenza (HPAI) H5N1. Although elevated strandings continue, neither UME (alone or in combination) provide cause for concern regarding population-level impacts to any of these stocks. For harbor seals, the population abundance is over 61,000 and annual mortality/serious injury (M/SI) (n=339) is well below PBR (1,729) (Hayes et al., 2020). The population abundance for gray seals in the United States is over 27,000, with an estimated overall abundance, including seals in Canada, of approximately 450,000. In addition, the abundance of gray seals is likely increasing in the U.S. Atlantic, as well as in Canada (Hayes et al., 2020).

Given the magnitude and severity of the impacts discussed above, and in consideration of the proposed mitigation and other information presented, Atlantic Shores' activities are not expected to result in impacts on the reproduction or survival of any individuals, much less affect annual rates of recruitment or survival. For these reasons, we have preliminarily determined that the take by harassment anticipated and proposed for authorization would have a negligible impact on harbor and gray seals.

Preliminary Negligible Impact Determination

No mortality or serious injury is anticipated to occur or proposed to be authorized. As described in the preliminary analysis above, the impacts resulting from the project's activities cannot be reasonably expected to, and are not reasonably likely to, adversely affect any of the species or stocks for which take is proposed for authorization through effects on annual rates of recruitment or survival. Based on the analysis contained herein of the likely effects of the specified activity on marine mammals and their habitat, and taking into consideration the implementation of the proposed mitigation and monitoring measures, NMFS preliminarily finds that the marine mammal take from all of Atlantic Shores' specified activities combined will have a negligible impact on all affected marine mammal species or stocks.

Small Numbers

As noted above, only small numbers of incidental take may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for specified activities other than military readiness activities. The MMPA does not define small numbers and so, in practice, where estimated numbers are available, NMFS compares the number of individuals estimated to be taken to the most appropriate estimation of abundance of the relevant species or stock in our determination of whether an authorization is limited to small numbers of marine mammals. When the predicted number of individuals to be taken is less than one-third of the species or stock abundance, the take is considered to be of small numbers. Additionally, other qualitative factors may be considered in the analysis, such as the temporal or spatial scale of the activities.

NMFS proposes to authorize incidental take (by Level A harassment and/or Level B harassment) of 16 species of marine mammal (with 17 managed stocks). The maximum number of instances of takes by combined Level A harassment and Level B harassment possible within any 1 year and proposed for authorization relative to the best available population abundance is less than one-third for all species and stocks potentially impacted.

For 15 of these species (15 stocks), less than 3 percent of the annual stock abundance is proposed to be authorized for take by Level A and/or Level B harassment and for 2 stock (both bottlenose dolphin), less than 6 percent is proposed for one stock (offshore) and less than 23 percent is proposed for the other (coastal). Specific to the North Atlantic right whale, the maximum amount of take, which is by Level B harassment only, is 21, or 6.2 percent of the stock abundance, assuming that each instance of take represents a different individual. Please see Table 26 for information relating to this small numbers analysis.

As noted in the final rule for the Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas Activities in the Gulf of Mexico (86 FR 5322, January 19, 2023), NMFS has determined that the small numbers finding should be applied to the annual take authorized per individual LOA, rather than to the total annual taking for all activities potentially occurring under the incidental take regulations. As described previously, Atlantic Shores has asked for two separate LOAs through which to authorize the requested take. The take authorized through each LOA would be less than that analyzed in the rule and would, together, not exceed the take analyzed. While NMFS still attaches the ultimate small numbers conclusion to the individual LOAs as described in the above-referenced Gulf of Mexico rule, where the entirety of the take allowable under regulations would be considered small numbers, as is the case here, then it follows that any smaller subset of that take authorized through subordinate LOAs will also qualify as small numbers. NMFS may, therefore, elect to present the supporting information for the entire amount of take for purposes of the small numbers analysis, rather than distinguishing the take that will be included in each LOA.

Based on the analysis contained herein of the proposed activities (including the proposed mitigation and monitoring measures) and the anticipated take of marine mammals, NMFS preliminarily finds that small numbers of marine mammals would be taken relative to the population size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

There are no relevant subsistence uses of the affected marine mammal stocks or species implicated by this action. Therefore, NMFS has determined that the total taking of affected species or stocks would not have an unmitigable adverse impact on the availability of such species or stocks for taking for subsistence purposes.

Classification

Endangered Species Act (ESA)

Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq.) requires that each Federal agency ensure that any action it authorizes, funds, or carries out is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of designated critical habitat. To ensure ESA compliance for the promulgation of rulemakings, NMFS consults internally whenever we propose to authorize take for endangered or threatened species, in this case with the NOAA GARFO.

The NMFS Office of Protected Resources is proposing to authorize the take of four marine mammal species which are listed under the ESA: North Atlantic right, fin, sei, and sperm whales. The Permit and Conservation Division requested initiation of section 7 consultation on July 19, 2023, with GARFO for the promulgation of the rulemaking. NMFS will conclude the Endangered Species Act consultation prior to reaching a determination regarding the proposed issuance of the authorization. The proposed regulations and any subsequent LOA(s) would be conditioned such that, in addition to measures included in those documents, Atlantic Shores would also be required to abide by the reasonable and prudent measures and terms and conditions of the Biological Opinion and Incidental Take Statement, as issued by NMFS, pursuant to section 7 of the Endangered Species Act.

Executive Order 12866

The Office of Management and Budget has determined that this proposed rule is not significant for purposes of Executive Order 12866, as amended by Executive Order 14094.

Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.), the Chief Counsel for Regulation of the Department of Commerce has certified to the Chief Counsel for Advocacy of the Small Business Administration that this proposed rule, if adopted, would not have a significant economic impact on a substantial number of small entities. Atlantic Shores is the sole entity that would be subject to the requirements in these proposed regulations, and Atlantic Shores is not a small governmental jurisdiction, small organization, or small business, as defined by the RFA. Under the RFA, governmental jurisdictions are considered to be small if they are governments of cities, counties, towns, townships, villages, school districts, or special districts, with a population of less than 50,000. Because of this certification, a regulatory flexibility analysis is not required and none has been prepared.

Paperwork Reduction Act

Notwithstanding any other provision of law, no person is required to respond to nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act (PRA) unless that collection of information displays a currently valid Office of Management and Budget (OMB) control number. These requirements have been approved by OMB under control number 0648–0151 and include applications for regulations, subsequent LOA, and reports. Submit any comments regarding any aspect of this data collection, including suggestions for reducing the burden, to NMFS (see ADDRESSES section) and through the Regulatory Dashboard at www.reginfo.gov.

Coastal Zone Management Act (CZMA)

The Coastal Zone Management Act (CZMA) requires Federal actions within and outside the coastal zone that have reasonably foreseeable effects on any coastal use or natural resource of the coastal zone be consistent with the enforceable policies of a state's federally-approved coastal management program (16 U.S.C. 1456(c)). NMFS has determined that Atlantic Shores' application for incidental take regulations is not an activity listed by the New Jersey Coastal Management Program pursuant to 15 CFR 930.53 and, thus, is not subject to Federal consistency requirements in the absence of the receipt and prior approval of an unlisted activity review request from the state by the Director of NOAA's Office for Coastal Management. Consistent with 15 CFR 930.54, NMFS published Notice of Receipt of Atlantic Shores' application for this incidental take regulation in the Federal Register on September 29, 2022 (87 FR 59061) and a 15-day extension on October 28, 2022 (87 FR 65193) and is now publishing the proposed rule. The state of New Jersey did not request approval from the Director of NOAA's Office for Coastal Management to review Atlantic Shores' application as an unlisted activity, and the time period for making such request has expired. Therefore, NMFS has determined the incidental take authorization is not subject to Federal consistency review.

Proposed Promulgation

As a result of these preliminary determinations, NMFS proposes to promulgate a LOA to Atlantic Shores authorizing take, by Level A harassment and Level B harassment, incidental to construction activities associated with Atlantic Shores South offshore of New Jersey for a 5-year period from January 1, 2025, through December 31, 2029, provided the previously mentioned mitigation, monitoring, and reporting requirements are incorporated.

Request for Additional Information and Public Comments

NMFS requests interested persons to submit comments, information, and suggestions concerning Atlantic Shores' request and the proposed regulations (see ADDRESSES ). All comments will be reviewed and evaluated as we prepare the final rule and make final determinations on whether to issue the requested authorization. This proposed rule and referenced documents provide all environmental information relating to our proposed action for public review.

Recognizing, as a general matter, that this action is one of many current and future wind energy actions, we invite comment on the relative merits of the IHA, single-action rule/LOA, and programmatic multi-action rule/LOA approaches, including potential marine mammal take impacts resulting from this and other related wind energy actions and possible benefits resulting from regulatory certainty and efficiency.

List of Subjects in 50 CFR Part 217

• Administrative practice and procedure
• Endangered and threatened species
• Fish
• Fisheries
• Marine mammals
• Penalties
• Reporting and recordkeeping requirements
• Wildlife

For reasons set forth in the preamble, NMFS proposes to amend 50 CFR part 217 to read as follows:

PART 217—REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS INCIDENTAL TO SPECIFIED ACTIVITIES

1. The authority citation for part 217 continues to read:

Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.

2. Add subpart EE, consisting of §§ 217.300 through 217.309, to read as follows:

Subpart EE—Taking Marine Mammals Incidental to the Atlantic Shores South Project Offshore of New Jersey