Feeding habits of northern fur seals (Callorhinus ursinus) in the eastern Bering Sea

• Main Author: Sinclair, Elizabeth
• Other Authors: Pearcy, William G., Hixon, Mark, Mate, Bruce, Loughlin, Tom, Whanger, Phillip, College of Oceanography, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Northern fur seal; Bering Sea; Callorhinus ursinus
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/6969z283p

This study was conducted to determine the composition and size of prey consumed by northern fur seals (Callorhinus ursinus) in the eastern Bering Sea. Eighty three northern fur seals were collected in the summer and fall of 1981, 1982, and 1985 for examination of gastrointestinal contents. A total of 139 midwater and bottom trawls were collected to determine the availability of potential prey. Analysis of trawls confirmed that seals are size-selective midwater feeders during their breeding and haul-out season in the eastern Bering Sea. Juvenile walleye pollock and gonatid squid, 5-20cm in body length, were the primary prey, but seal prey varied among years and between nearshore and pelagic sample locations. Interannual variation in body sizes of walleye pollock consumed by seals was related to pollock year class strength. The identification of pollock and gonatid squid as primary fur seal prey in the eastern Bering Sea was consistent with previous reports. However, Pacific herring and capelin, previously considered important fur seal prey werE absent in this study.