With only three U.S. rookeries—two of which found in the remote regions of Alaska—coupled with their unique life histories of hauling out only to breed and give birth, northern fur seals (Callorhinus ursinus) are one of the most elusive pinnipeds to grace the U.S. Pacific coastline. It is estimated that 80% of the world’s northern fur seals are found at these rookeries—the largest rookery being the Pribilof Islands where 74% of the world’s population resides. Despite the apparent robustness of this population, it has declined by approximately 30% since 1992, prompting the National Marine Fisheries Service (NMFS) to list the species as depleted under the Marine Mammal Protection Act (MMPA) in 1988. This listing has remained listed since.
Because northern fur seals and Steller sea lions overlap in range, habitat, prey, and characteristics of the decline, leading hypotheses associated with the decline of northern fur seals have been similar to those of Steller sea lions. In 2005, the Alaska SeaLife Center (ASLC) began researching northern fur seals at Russian and U.S. rookeries. Federal appropriations awarded in 2005 to the ASLC required that we initiate northern fur seal studies as this population remains in threatening jeopardy. Northern fur seal research at the ASLC, as a result, is the newest addition to our Pinniped Program, which also includes Steller sea lions and harbor seals. Our northern fur seal research has continued to employ, develop and incorporate cutting edge technology into its research while also conscientiously making an effort to reduce its impact on this species.
Each year since 2004, the ASLC has conducted northern fur seal and Steller sea lion research at a remote field station located at one of the Russian Kuril Islands called Paramushir Island. There, our research efforts have concentrated on the foraging ecology and bioenergetics of both Steller sea lions and northern fur seals. Modeled after our own Steller South Beach, the field station functions as a temporary holding facility where short-term studies can be performed on adult females and their pups. After two weeks, animals are returned to their origin of capture.
To learn more about the specific research projects involving northern fur seals, click on the research topics below:
Foraging Ecology There are many components necessary for northern fur seal survival, but perhaps the most important is the ability to find food or prey. Metabolically, they must be able to locate, capture, and assimilate prey while expending less energy than the food they are capturing. To study this dynamic relationship—predator and prey—Alaska SeaLife Center research has investigated prey availability, fur seal foraging and assimilation efficiencies; prey ingestion rates; energetics of inter- and intra-specific prey; and metabolic demands of fur seals.
How nutritionally fit are northern fur seals in Russia? Scientists are examining a suite of physiological parameters that explore the overall health of these animals. Of particular interest is the energy transfer between mother and pup during the critical weeks following birth. Because northern fur seals undergo drastic fasting bouts, it is important to determine how they metabolically adjust to this physiological change, and while doing so, provide enough energy for their pup to survive.
EndocrinologY & Contaminants Lipids are essential building blocks for blubber development. Blubber and lipids maintain most marine mammals' abilities to thermoregulate (warm body in a cold ocean), promote growth, provide long-term engergy stores, and in the case of reproductive females, nurturing developing fetuses and nursing pups. Our researchers are investigating how and the degree to which contaminants such as organopollutants bioaccumulate in the blubber. Organopollutants, in large concentrations, can have profound effects upon the growth and reproduction of certain species.