NOAA Fisheries News Releases
NEWS RELEASE
December 3, 2009
Sheela McLean, Public Affairs
(907) 586-7032
NOAA RELEASES COUNT OF STELLER SEA LION PUPS
Researchers from NOAA’s Alaska Fisheries Science Center have published the results of their2009 count of Steller sea lion pups in Alaska. With the assistance of NOAA’s Aircraft Operations Center in Monterey, California, researchers conducted an aerial photographic survey of all rookeries and major haulouts throughout most of the species’ range in Alaska from 24 June through 15 July 2009.
“We expected to see the increased Steller sea lion numbers in Southeast Alaska again,” said Doug DeMaster, Director of the Alaska Fisheries Science Center. “The mixed results in the western population, however, indicate that some areas have improved in numbers while others continue to decline, especially the Western Aleutian Islands.”
While Steller sea lion pup production by Alaska’s western stock increased from 9,950 in 2005 to 11,120 in 2009 overall, there was considerable variability. During this period, pup counts increased 18% throughout the Gulf of Alaska and in the eastern Aleutian Islands, but were 6% lower in the western and central Aleutian Islands.
The number of Steller sea lion pups counted in 2009 in Southeast Alaska (7,462)—part of the threatened eastern stock– exceeded any previous counts going back to the 1960s. The new data indicate that pup production has increased at a rate of almost 4% per year at Southeast Alaska’s five major rookeries since the late 1970s.
Another index that Steller sea lion biologists watch is the ratio of pups to older animals, since it provides an indication of changes in birth rates. The 2009 numbers suggest that the western Alaska Steller sea lion population has a lower pup to non-pup ratio than the population that inhabits Southeast Alaskan waters.
The number of Steller sea lions in the western stock declined by 75% between 1976 and 1990. The extent of this decline led NOAA’s Fisheries Service to list the Steller sea lion as threatened range-wide under the Endangered Species Act in April 1990. In the 1990′s the decline continued for the western stock in Alaska, which was declared endangered in 1997. The eastern stock remains listed as threatened.
Details of the 2009 pup count can be found at http://www.afsc.noaa.gov/nmml/PDF/SSL-Survey-09-memo-11-30-09.pdf.
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, visitalaskafisheries.noaa.gov or: www.afsc.noaa.gov.
