National Marine Fisheries Service (NMFS) provides federal management for Steller sea lions in the United States. All Steller sea lions were listed as threatened under the ESA in 1990 due to severe declines in the Western portion of their range. At that time, only one stock or population was recognized. In 1997, two Distinct Population Segments (DPS) were recognized – an Eastern DPS and a Western DPS. The Western DPS was reclassified to endangered status, and the Eastern DPS remained classified as threatened.
In 2013, due to steady positive growth, the Eastern DPS was delisted from the ESA. It remains classified as “Depleted” under the MMPA while post-delisting monitoring occurs to ensure that removing the protections the ESA offers does not negatively impact the population. The population will be monitored for 10 years under the Post Delisting Monitoring Plan to ensure that the protection measures offered by the MMPA are sufficient.
The Western Stock or DPS includes all of Prince William Sound westward to the tip of the Aleutians. This includes PWS, Cook Inlet, Kodiak, Bristol Bay, Aleutian Islands and the Pribilof Islands. Recent surveys indicate that the population at this point has been generally stable since 2004, however still at greatly reduced numbers from its earlier population estimate in the 1970’s and earlier. Not all areas of the Western Population are stable however, the central and western Aleutians still continue to experience a downward population trend. Based on the 2017 survey results, the National Marine Mammal Laboratory estimates that there are 42,315 juvenille and adult Steller sea lions in the Western Population.
The Eastern Stock of Stellers extends southward from Cape Sucking to California. Sea lions in Southeast Alaska, British Columbia, Washington and Oregon have shown steady increases since 1997. Counts in California and Southern California have shown declines from historic numbers. However, the stock overall has been slowly increasing in numbers since the mid-1970’s.
The 2017 survey also included a pup survey over much of the range of sea lions in Alaska. Modeling the survey data, the Marine Mammal Laboratory estimates that there are 11,953 sea lion pups in the Western Population. Sharp declines were seen in the Central and Eastern Gulf of Alaska areas, as well as the Central Aleutians. As with the adults, pup counts continue to decline in the Western Aleutians. Declines were also noted in Southeast Alaska, with 6% fewer pups counted than in 2015.
Steller sea lions are traditionally an important cultural subsistence resource and this practice continues today.
Section 119 of the MMPA calls for co-management of the subsistence harvest of marine mammals and Secretarial order #3225 calls for meaningful participation by Alaska Natives in the subsistence management of species listed under the ESA. While we do not have a co-management agreement for Steller sea lions, TASSC is currently working with the National Marine Fisheries Service on sea lion issues.