Holding that in determining whether to vacate regulations that violate the APA, a court should consider “the seriousness of the [rule's] deficiencies (and thus the extent of doubt whether the agency chose correctly) and the disruptive consequences of an interim change that may itself be changed.”
Holding that a challenge to several agency management measures governing the 1986 salmon fishing season was not mooted by the close of the season because "the relief for the alleged overfishing in 1986 can take the form of higher escapement provisions and lower quotas in" subsequent seasons