Analysis of contemporary genetic structure of even-broodyear populations of Asian and western Alaskan pink salmon, Oncorhynchus gorbuscha

Even-year pink salmon (Oncorhynchus gorbuscha) populations from the Russian Far East and Japan exhibit genetic structure that reflects their geographi c relationships. Extension of genetic analysis to include data from Bering Sea and northern Gulf of Alaska populations shows a combined genetic struct ure with three prominent groupings that correspond to the three North Pacif ic Ocean basins-the Sea of Okhotsk, the Bering Sea, and the Gulf of Alaska- and that are consistent with geographic, geologic history, and oceanographi c features. Analysis of 35 Asian collections at 39 variable allozyme loci ( 54 total) allowed examination of population structure of even-year pink sal mon. Although most (98.5%) of the genetic variation occurred within collect ions (populations), the 1.5% attributable to among-collection divergence wa s sufficient to detect population structure and provide a basis for some st ock separation. Differences between western Kamchatka populations and easte rn Sakhalin Island populations indicate that little gene flow occurs betwee n those regions and argues against an interregional fluctuating stock model .