## Facts

- The Marine Mammal Protection Act (MMPA) imposes a general moratorium on taking marine mammals, allowing limited exceptions, including permits for incidental take in commercial fishing if statutory findings are met.
- A Japanese salmon fishing cooperative sought an incidental-take permit to allow marine mammals to be taken unintentionally in high-seas gillnet salmon fishing within U.S. conservation waters.
- The Secretary of Commerce, after notice-and-comment proceedings, issued a final rule granting a three-year permit authorizing incidental take of specified numbers of Dall’s porpoise, while declining to authorize takes of other marine mammals due to insufficient population information.
- Alaskan commercial salmon fishermen and environmental organizations challenged the permit, arguing that scientific uncertainty and data gaps prevented the required findings that the authorized take would be negligible and consistent with maintaining the stock at optimum sustainable population.
- The district court issued a preliminary injunction barring implementation of the permit pending review, and the federal government and the Japanese cooperative appealed.

## Issues

1. Whether the Secretary lawfully issued an MMPA incidental-take permit absent an adequately supported finding that authorized takes would have a negligible impact on the affected stock and be consistent with maintaining optimum sustainable population.
2. Whether the agency could rely on incomplete or uncertain scientific information to satisfy the MMPA’s substantive permit prerequisites.
3. Whether the district court properly granted preliminary injunctive relief based on likelihood of success on the merits and irreparable harm.

## Decision

- The D.C. Circuit affirmed the preliminary injunction in substantial part, holding that the record did not adequately support the statutory findings required to authorize incidental take of Dall’s porpoise.
- The court concluded that, given significant scientific uncertainty and gaps regarding population size, structure, trends, and cumulative mortality, the Secretary’s “negligible impact” determination was not sufficiently supported.
- The court rejected arguments that prior permitting practice or treaty-related considerations could displace or dilute the MMPA’s protective requirements.
- The court held that petitioners demonstrated likely success on the merits and that deaths of marine mammals constitute irreparable harm supporting injunctive relief.
- A dissent argued the majority failed to defer to agency scientific judgment and demanded an unrealistic degree of certainty.

## Legal Principles

- The MMPA is a protective moratorium statute; exceptions authorizing incidental take are narrowly construed and must be justified by record-supported statutory findings.
- “Negligible impact” and optimum sustainable population requirements demand an evidence-based showing; agency confidence or absence of proven harm is not enough.
- When scientific uncertainty prevents reliable findings about population status and resilience, that uncertainty weighs against authorizing incidental take under the MMPA.
- Prior agency practice and international fishery arrangements do not excuse compliance with the MMPA’s explicit prerequisites for permits.
- Under arbitrary-and-capricious review, courts may closely evaluate whether the administrative record supports the specific findings the statute requires, and irreparable environmental injury supports injunctive relief.

## Conclusion

The D.C. Circuit held that the MMPA required the Secretary to support incidental-take authorization with reliable, record-based findings of negligible impact and consistency with optimum sustainable population, and it affirmed injunctive relief where significant scientific uncertainty and data gaps undermined those findings.


Kokechik Fishermen’s Ass’n v. Sec’y of Com., 839 F.2d 795 (D.C. Cir. 1988)