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

Issue:

Author(s): 
Farley, Edward V. Jr, James M. Murphy, Milo D. Adkison, Lisa B. Eisner, John H. Helle, Jamal H. Moss, and Jennifer Nielsen
Cover date: 
2007
PDF: 
Pages: 
121–130
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.