Microsatellite Identification of Canadian Sockeye Salmon Rearing in the Bering Sea

Abstract

The stock composition of sockeye salmon Oncorhynchus nerka caught in the central Bering Sea in the summer of 2009 was estimated to evaluate migration patterns of salmon of Canadian origin, which have not been demonstrated previously to rear in the Bering Sea. The variation at 14 microsatellites was analyzed for 450 immature sockeye salmon, and a baseline of 387 populations from Japan, Russia, Alaska, Canada, and Washington State was used to determine the stock composition of the fish sampled. Sockeye salmon originating from Alaska were the most abundant in the catch, comprising 86.0% of all sockeye salmon caught, the catch being dominated by sockeye salmon of Bristol Bay origin. Russian-origin sockeye salmon accounted for 10.2% of the catch, while Canadian-origin sockeye salmon accounted for 3.8% of the catch. Salmon from Canada were estimated to originate from the Fraser River, Rivers Inlet (Owikeno Lake), the Skeena River (Babine Lake), the Stikine River, and the Alsek River, British Columbia. These results indicate that the central Bering Sea provides a summer rearing area for some Canadian sockeye salmon.

Received August 12, 2010; accepted December 13, 2010

ACKNOWLEDGMENTS

We thank the captain and crew of the RV Hokko-maru for sample collection in the Bering Sea. A very substantial effort has been involved in obtaining samples to develop the baseline used in the analysis. In addition to those acknowledged by Beacham et al. (2005), N. V. Varnavskaya provided additional samples to enhance the Russian baseline, the Alaska Department of Fish and Game Anchorage genetics laboratory provided the new Bristol Bay and Cook Inlet samples, Fisheries and Oceans Canada (DFO) staff provided the new samples from Canada outside of the Fraser River, Pacific Salmon Commission and DFO staff provided samples from the Fraser River, and the National Marine Fisheries Service and the Idaho Department of Fish and Game provided samples from the Columbia River. Brenda McIntosh conducted the laboratory analysis of microsatellite variation for the sockeye salmon sampled from the Bering Sea. Lana Fitzpatrick drafted the map outlining catch locations. Funding for the study was provided by Fisheries and Oceans Canada.