NOAA Fisheries News Releases
NEWS RELEASE
November 19, 2008
Sheela McLean, Public Affairs
(907) 586-7032
Alaskan Steller Sea Lion Count Reported
NOAA scientists have completed their analysis of 2008 Steller sea lion survey results.
"This year’s numbers reinforce last year’s incomplete survey," said Doug DeMaster, Director of NOAA’s Alaska Fisheries Science Center. "With increased counts in some places and decreases in others, the overall trend since 2004 in Alaska’s western population of Steller sea lions is stable or declining slightly."
The last complete scientific survey of Steller sea lion sites in Alaska was in 2004, explained Lowell Fritz of the Alaska Fisheries Science Center’s National Marine Mammal Laboratory. Weather and mechanical problems forced incomplete aerial surveys in both 2006 and 2007.
This year, researchers were able to conduct aerial surveys for adult and juvenile Steller sea lions between June 7 and July 6, when the largest numbers of Steller sea lions are onshore to give birth and breed.
Between 2000 and 2004, the endangered population segment of Steller sea lions in western Alaska from Cape Saint Elias to Attu Island increased approximately 3% per year, the only increasing trend for Steller sea lions in western Alaska since the 1970s. Since 2004, however, the trend has been stable or slightly decreasing. The population in western Alaska is currently thought to number about 45,000.
The eastern population segment---from Cape Saint Elias down into California--has shown a substantial increase over the last 30 years.
Despite the stability or slight decline observed in the overall western Alaska population, scientists continued to find considerable regional variability in population trends between 2004 and 2008. The percentages listed below are percent changes between years:
- the eastern Aleutian Islands is the only consistently increasing region (+7%);
- the central and western Aleutian Islands declined at relatively high rates (-30% and -16%, respectively);
- the central and western Gulf of Alaska increased between 2004 and 2007, but declined slightly between 2007 and 2008; and
- the eastern Gulf of Alaska increased by 35%, but likely because of immigration of eastern distinct population segment animals from southeast Alaska.
The Steller sea lion was listed as a threatened species under the Endangered Species Act in1990 due to substantial population declines. In 1997, the Steller sea lion was split into western and eastern distinct population segments. At that time, the western distinct population segment was classified as endangered due to persistent declines, while the status of the eastern segment remained threatened.
NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources. Visit www.noaa.gov. To learn more about NOAA Fisheries in Alaska, visit alaskafisheries.noaa.gov or www.afsc.noaa.gov.