Single-Nucleotide Polymorphic Genotypes Reveal Patterns of Early Juvenile Migration of Sockeye Salmon in the Eastern Bering Sea

Abstract

We estimate patterns of nearshore migration in the eastern Bering Sea for out-migrating Bristol Bay sockeye salmon Oncorhynchus nerka in their first year at sea. Over 3,000 juveniles were collected during the late summer of 2005–2007 as part of the Bering–Aleutian Salmon International Survey and tested with a regional genetic baseline of 45 single-nucleotide polymorphisms. Population-specific and westward migrations from natal rivers were evident. Populations from Wood River and northwestward predominated in the northern latitudes of Bristol Bay and the eastern Bering Sea and populations from the Egegik River and southwestward in the southern latitudes, while the populations spawning at the head of Bristol Bay had the highest proportions in the middle latitudes. These patterns were stable across years, apparently unaffected by marine productivity and temperature. This continuum of marine migratory patterns most likely reflects stable and population-specific adaptations to buffer the distribution of dynamically shifting marine resources. As monitoring continues, these juvenile surveys will accumulate information to refine predictions of the magnitude of adult returns to their respective rivers of origin and thereby assist in the management of this valuable resource.

ACKNOWLEDGMENTS

We thank the staff of the Auke Bay Laboratory for collection of the samples as well as the captains and crews of the research vessels Sea Storm and Northwest Explorer. We also thank Tyler Dann, Alaska Department of Fish and Game, who facilitated the use of the Habicht et al. (2010) single-nucleotide polymorphism baseline and two anonymous reviewers for insightful comments. Carita Pascal, University of Washington, provided excellent laboratory assistance. Funding for this project was provided by the Gordon and Betty Moore Foundation through a grant to the School of Aquatic and Fishery Sciences, University of Washington.