On July 23, 2013, the U.S. Court of Appeals for the Ninth Circuit affirmed (pdf) a lower court decision upholding restrictions on commercial fishing in Alaska to protect the western Distinct Population Segment (DPS) of the Steller sea lion (Eumetopias jubatus), which is listed under the Endangered Species Act (ESA). The measures, imposed in 2010 by the National Marine Fisheries Service (NMFS), restrict the mackerel and cod fisheries in the western Aleutian Islands. NMFS determined such restrictions were necessary to ensure an adequate supply of prey for the western DPS of the species.

The commercial fishing industry and the State of Alaska challenged the restrictions, arguing that NMFS violated the ESA by basing the fishing restrictions on declines in sub-region populations, rather than on the entire population of Steller sea lions. Plaintiffs also argued that NMFS utilized the wrong standard when concluding there was a causal link between continued fishing and the population decline of the species.

Affirming a decision by the U.S. District Court for the District of Alaska, the Ninth Circuit held that NMFS did not violate the ESA when it based the restrictions on declines in sub-regions of the population. The Court further held that “the agency utilized appropriate standards to find that continuing previous fishing levels in those sub-regions would adversely modify the critical habitat and jeopardize the continued existence of the entire population.”

The western DPS of the species was listed as endangered under the ESA in 1997.