Early marine growth in relation to marine-stage survival rates for Alaska sockeye salmon ( Oncorhynchus nerka )

Edward V. Farley; J.M. Murphy; Milo D. Adkison; Lisa B. Eisner; J.H. Helle; J.H. Moss; Jennifer L. Nielsen

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USGS · 70032215

Early marine growth in relation to marine-stage survival rates for Alaska sockeye salmon ( Oncorhynchus nerka )

Edward V. Farley·J.M. Murphy·Milo D. Adkison·Lisa B. Eisner·J.H. Helle·J.H. Moss·Jennifer L. Nielsen

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Abstract

We tested the hypothesis that larger juvenile sockeye salmon ( Oncorhynchus nerka ) in Bristol Bay, Alaska, have higher marine-stage survival rates than smaller juvenile salmon. We used scales from returning adults (33 years of data) and trawl samples of juveniles (n= 3572) collected along the eastern Bering Sea shelf during August through September 2000−02. The size of juvenile sockeye salmon mirrored indices of their marine-stage survival rate (e.g., smaller fish had lower indices of marine-stage survival rate). However, there was no relationship between the size of sockeye salmon after their first year at sea, as estimated from archived scales, and brood-year survival size was relatively uniform over the time series, possibly indicating size-selective mortality on smaller individuals during their marine residence. Variation in size, relative abundance, and marine-stage survival rate of juvenile sockeye salmon is likely related to ocean conditions affecting their early marine migratory pathways along the eastern Bering Sea shelf.

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Edward V. Farley, J.M. Murphy, Milo D. Adkison, Lisa B. Eisner, J.H. Helle, J.H. Moss, Jennifer L. Nielsen. 2007. Early marine growth in relation to marine-stage survival rates for Alaska sockeye salmon ( Oncorhynchus nerka ). https://pubs.usgs.gov/publication/70032215

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