Steller sea lions and fisheries : competition at sea? ...

• Main Author: Hui, Tabitha Cheng Yee
• Format: Text
• Language: English
• Published: University of British Columbia 2011
• Subjects: Bering Sea; Gulf of Alaska; Pacific; Atka; Alaska; Aleutian Islands
• Online Access: https://dx.doi.org/10.14288/1.0071644; https://doi.library.ubc.ca/10.14288/1.0071644

A leading hypothesis to explain the decline of Steller sea lions (Eumetopias jubatus) in western Alaska is the reduction of prey abundance or change in prey distributions caused by commercial fisheries. We sought to improve on past studies that attempted to assess competition between sea lions and fisheries by estimating the local amounts of prey accessible to sea lions. We explored the relationships between sea lion population trends, fishery catches and the prey biomass accessible to sea lions around 33 rookeries from 2000-2008. We focused on three commercially important species that dominate the sea lion diet: walleye pollock, Pacific cod and Atka mackerel. We estimated available prey biomass by removing fishery catches from predicted prey biomass distributions in the Aleutian Islands, Bering Sea and Gulf of Alaska; and modelled the likelihood of sea lions foraging at different distances from rookeries (accessibility) using satellite telemetry locations of tracked animals. We combined this accessibility ...