Microsatellite Identification of Canadian Sockeye Salmon Rearing in the Bering Sea

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.