Research > Steller
sea lion research
Sea Lion Research - The Problem
Steller sea lion research
Since 1980, more than 75 percent of the Steller sea lion population has
disappeared, leaving the current wild populations with less than
75,000 individuals. in 1990, Steller sea lions were listed as "threatened"
under the United States Endangered Species Act. In 1997, the U.S.
National Marine Fisheries Service reclassified the western population
of Steller sea lions in Alaska as "endangered". The eastern population
(from Southeast Alaska through California) is stable.
Scientists are currently researching why Steller
sea lion populations are declining. possible reasons for this include
an increase in parasites, disease, predation by killer whales , quality
and distribution of food, environmental factors and nutritional stress
caused by natural changes in the abundance of key prey species, or by competition with humans and other species for food.
Since 1993, University researchers with the
Consortium have been comparing the behaviors, diets, and movements
of Steller sea lions in Southeast Alaska (where the population is considered
abundant) to the Western Gulf (where the largest declines have occurred).
Some of the field sites are shown on the map.
with the Consortium have been comparing the behaviors, diets, and
movements of Steller sea lions in Southeast Alaska (where the population
is considered abundant) to the Western Gulf (where the largest declines
have occurred). Some of the field sites are shown on the map.
Many of the field studies are being undertaken
with support from the Alaska Department of Fish and Game. We are also
engaged in a captive research program at the Vancouver Aquarium to better understand the nutritional needs of
Steller sea lions, and to develop better techniques for studying Steller
sea lions in the wild. Other studies involve laboratory tests, data
analysis and computer simulations.
The Consortium studies are a balance of short and long term projects
designed to test the various hypotheses that have been put forward
to explain the decline of Steller sea lions.The studies are integrated
and draw on the expertise and talents of university based physiologists,
ecologists, marine mammalogists, fisheries specialists and oceanographers.
Only a concerted effort and a commitment to long term research will
determine the cause of changes in the North Pacific. Solutions are
unlikely to come quickly and need a concerted effort.
Decline of Steller Sea Lions - The Nutritional Stress Hypothesis