50 C.F.R. § 32.4
Wildlife refuge areas may be opened to sport fishing only after a determination is made that this activity is compatible with the purposes for which the refuge was established. In addition, the sport fishing program must be consistent with principles of sound fishery management and otherwise be in the public interest. The opening or closing of wildlife refuge areas to fishing is subject to the rulemaking requirements of the Administrative Procedure Act ( 5 U.S.C. 551 et seq. ). Lands acquired as "waterfowl production areas" are open to sport fishing subject to the provisions of State laws and regulations and the pertinent provisions of parts 25 through 31 of this subchapter: Provided, that fishing or entry on all or any part of individual areas may be temporarily suspended by posting upon occasions of unusual or critical conditions of, or affecting, land, water, vegetation or fish and wildlife populations.
50 C.F.R. § 32.4