NORTHERN FUR SEAL RESEARCH
Approximately 80% of the world’s population of northern fur seals (Callorhinus ursinus) once bred and gave birth on the Pribilof Islands of St Paul and St George in the Bering Sea. However, the Pribilof population has declined significantly since then and now numbers less than 20% of its former peak abundance. Scientists are working to understand why the population is declining.
There is speculation that large, ecosystem-wide changes may be affecting multiple species of marine mammals and sea birds in the Bering Sea. Three hypotheses have been suggested to explain the continued decline of northern fur seals on the Pribilof Islands: ocean climate change, competition with commercial fisheries, and increased predation. Consortium researchers are testing these hypotheses with field and captive studies to help formulate science-based recovery strategies.
In the lab
Consortium researchers care for 6 female fur seals housed at the Marine Mammal Energetics and Nutrition Laboratory at the Vancouver Aquarium. The fur seals afford an opportunity to collect information that cannot be obtained in the wild. This includes determining 1) how much fish northern fur seals require, 2) what limits their ability to find food, and 3) how do they adapt physiologically to disruptions and changes in the quantity and quality of prey available to them?
In the field
Consortium researchers have been studying the diets and foraging behavior of fur seals on St. Paul Island in the central Bering Sea, and comparing them with the diets and foraging behavior of a small but increasing population of northern fur seals breeding on Bogoslof Island along the Aleutian Islands chain. The studies are determining whether the differences in population trends are related to differences in diets, durations of foraging trips, oceanography, or some other factor. Consortium researchers have also been investigating what role predation by killer whales could be playing in the population decline.