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Sea Otter Research


SEA OTTER Research

Sea otters (Enhydra lutris) have had a long history of federal protection dating back to 1911 when they were hunted to near extinction—the International Fur Seal Treaty was one of the earliest forms of legislation protecting marine mammals. Despite subsequent federal protection under the Marine Mammal Protection Act and the Endangered Species Act, southern and northern sea otters continue to be a threatened species. Most recently, the northern population (Enhydra lutris kenyoni) located in southwest Alaska was listed as threatened in 2005. Since the 1990's northern sea otters have undergone one of the worst population declines of carnivorous mammals in recorded history—and the Alaska SeaLife Center (ASLC) is trying to find out why.

In 2003, the ASLC was awarded congressional appropriations to initiate a dedicated Sea Otter Research Program. Under the direction of Dr. James Estes, one of the world’s experts on sea otters, the ASLC has been examining why northern sea otter populations have declined precipitously, and moreover, how to aid in the recovery efforts of this species. As funding became available, research expanded to include another subspecies of sea otter, E. l. lutris, which is commonly found along the Russian Commander and Kuril Island chains. Both the northern sea otter and E. l. lutris share similar biogeography and habitats, but E. l. lutris has not experienced population declines—in fact, the opposite. This population is experiencing population growth at or near carrying capacity.

With our unique laboratory facilities and abilities to conduct field work in both Russia and the Aleutian Archipelago, our research has focused on ecological, epidemiological, and habitat-specific priorities potentially linked to the otter’s lack of recovery. Our recent discoveries in killer whales and their role as ocean predators have been the result of cutting-edge technologies and applications designed at the ASLC and by our collaborators. To learn more about our sea otter research projects, click on the subjects below:


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Photo Gallery
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Causes of Decline
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Predation Studies
Predation Studies
Predation by killer whales (Orcinus orca) is thought to be one of the leading causes for sea otter decline in southwest Alaska. Unclear, however, is the direct impact they have as observed mortality by predation events still remains low. Our scientists are investigating the foraging ecology of killer whales, i.e. determining their movements, migration routes, and dive patterns using remotely applied satellite transmitters. We are also examining how much energy a transient killer whale needs in order to survive. Lastly, our collaborators are determining if transient killer whales switched their prey base as some literature suggests.
Population STUDIES
Population STUDIES
In a comparative study, ASLC scientists are examining the population changes between the Russian Commander Islands versus the Aleutian Archipelago. Recently the Commander Island populations have shown population growth at or near carrying capacity whereas some areas in the Aleutian Islands have experienced declines by more than 95%. Interestingly, these locations share many similar biogeographical features which have scientists wondering why such a large disparity.
Epidemiological Studies
Epidemiological Studies
Disease, whether it is viral, bacterial, or parasitic, can play a signifcant role in mortality for any population. ASLC scientists are investigating the direct and indirect effects of disease in northern sea otter populations. Live, moribound otters and stranded carcasses have been collected and necropsied to determine causes of mortality in areas affected by population declines. Tissue samples have also been collected for future genetic and contaminant studies.
Environmental Monitoring
Environmental Monitoring
Sea otters and the kelp forest ecosystem have a strong relationship with one another. The strength or robustness of one, often influences the productivity of the other. Often then, are sea otters considered a keystone species, an important species vital to the overall health of ecosystems. ASLC collaborators are currently investigating the benthic invertebrate communities to better understand the overall ecosystem health and how it relates to otter populations in the Aleutian and Commander Island chains.

 

 

 

 

 

 

 

 

 

 

 

 

 

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