Stock Origins of Chum Salmon (Oncorhynchus keta) in the Gulf of Alaska during Winter as Estimated with Microsatellites

A microsatellite baseline incorporating over 53,000 chum salmon (Oncorhynchus keta) sampled from over 380 locations in Asia and North America was applied to estimate stock composition in mixed-stock fishery samples from the Gulf of Alaska. High resolution of these mixed-stock samples was possible, with 1 reporting group developed for Korean populations, 7 groups for Japanese populations, 8 groups for Russian populations, 15 groups for Alaskan populations, 5 groups for Canadian Yukon River populations, 16 groups for British Columbia populations, and 5 groups for Washington populations. In February 2006 samples from the Gulf of Alaska (145°W), chum salmon in more northern areas (54°N) were primarily of North American origin (55% British Columbia, 30% Alaska), but in more southern areas (48°N), nearly 40% of chum salmon sampled were of Japanese origin (Sea of Okhotsk and Pacific coasts of Hokkaido), and 30% were of Russian origin (Kamchatka and northeast Russia). Ocean age-1 chum salmon spending their first winter in the Gulf of Alaska were almost entirely from southeast Alaska (39%), Prince William Sound (31%), or southern British Columbia (26%). However, by the second winter, 30% of ocean age-2 chum salmon were identified as of Asian origin (18% Japanese, 12% Russian).