The Eastern Population of Steller Sea Lions, Now Recovered, is Off the Threatened Species List
Once a species is listed as threatened or endangered, unless new information indicates that it never should have been listed in the first place, there are only two ways to get off the list: either go extinct, or recover. For the first time in 19 years, and only the second time ever, a de-listing by NOAA Fisheries is cause for celebration. The eastern population of Steller sea lions, listed as threatened almost a quarter century ago, has recovered its way off the list. The only other time NOAA took such an action was in 1994, with the now thriving eastern population of North Pacific gray whales.
As marine predators that forage on fish, squid, and other species, Steller sea lions are vital links in the marine food web. By reasserting its role in the ecosystem, the recovered population, which ranges from south-central Alaska down to central California, is contributing to the long-term health of the marine environment. This recovery also highlights the value of the Endangered Species Act in securing intact marine ecosystems for future generations.
The Endangered Species Act is imperfectly named in that its protections are often applied not to entire species, but rather to distinct populations within a species. In the case of Steller Sea Lions, the entire species was listed as threatened in 1990. But further research into their genetics and population structure led scientists to split the species into two distinct populations in 1997. At that time, the eastern population remained on the threatened species list while the western population was given the more severe classification of endangered.
NOAA Fisheries proposed delisting the eastern population following the completion of a five-year status review in April 2012. According to this review, the eastern population appears to have grown from about 18,000 in 1979 to over 70,000 in 2010. This works out to an estimated annual growth rate of 4.18%, exceeding the 3% target specified in the population’s 2008 recovery plan.
In addition to studying historic population trends, NOAA scientists also analyzed potential threats going forward and found none that present a danger of extinction in the foreseeable future.
NOAA Fisheries, along with partners in Alaska, Washington, Oregon, and California, has developed a ten-year monitoring plan for the recovered population. “We will keep an eye on population trends and also on emerging threats,” said Jon Kurland, the Assistant Regional Administrator for Protected Resources with NOAA Fisheries’ Alaska Region. “That way if we see a problem, we can take action early on so that listing doesn’t become necessary again.”
The eastern population of Steller Sea Lions will still be safeguarded by the Marine Mammal Protection Act, which applies to all marine mammals whether endangered or not.
Although the eastern population is now de-listed, their western cousins remain endangered. NOAA and other scientists will continue to study Steller sea lions to better understand why one population has recovered while the other has not. Hopefully, this research will yield insights that will speed the delisting of the western population as well.