Predator aggregations during eulachon Thaleichthys pacificus spawning runs

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 231:229-236 (2002) - doi:10.3354/meps231229 Predator aggregations during eulachon Thaleichthys pacificus spawning runs Brian H. Marston1,*, Mary F. Willson2, Scott M. Gende3 1Alaska Department of Fish and Game, Wildlife Conservation, 333 Raspberry Road, Anchorage, Alaska 99518, USA 25230 Terrace Place, Juneau, Alaska 99801, USA 3US Forest Service, Pacific Northwest Research Station, 2770 Sherwood Lane, Juneau, Alaska 99801, USA *E-mail: brian_marston@fishgame.state.ak.us ABSTRACT: Predators congregated in large numbers during the 1996 and 1997 spring spawning runs of eulachon Thaleichthys pacificus Richardson (Osmeridae) in the lower reaches of the rivers entering Berners Bay, southeastern Alaska. Predator abundance rose rapidly at the beginning of the runs and was significantly correlated with an index of eulachon abundance within years. Gulls (Laridae) were the most abundant predators, with a daily average peak of 40000 during the 1996 run, at a density of 3000 km-2. A daily average peak of over 250 Steller sea lions Eumetopias jubatus and harbor seals Phoca vitulina fed on eulachon early in the run in both years. Daily average counts of bald eagles Haliaeetus leucocephalus approached 600 on the lower reaches of the rivers, and many others foraged upstream. Eulachon are unusually high in lipid content, and many of the prodigious spawning runs in Alaska and British Columbia occur in spring, when predator energy demands are high. We suggest that spring spawning runs of eulachon and other forage fishes are an ecological cornerstone for regional coastal ecosystems, supporting large numbers of wildlife species. KEY WORDS: Eulachon · Thaleichthyes pacificus · Osmeridae · Southeast Alaska · Steller sea lion · Harbor seal · Laridae Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 231. Online publication date: April 23, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.