Allozyme variability of Oncorhynchus nerka in Japan

We examined allozymic variation in 65 protein-coding loci in three samples of sockeye salmon (Oncorhynchus nerka) from Hokkaido, and Honshu, Japan. Ov erall, six variable loci were seen and each of the three samples was variab le at 3-5 loci. Two loci, mAH-1,2*, and ALAT*, were variable at the P-0.95 level. Average heterozygosity ranged from 0.012 to 0.013, representing some of the lowest recorded values for the species. Although frequencies of ALA T* alleles differed significantly among the three samples. the overall chi (2) for six polymorphic loci was not statistically significant. New data fo r four Russian samples at 45-64 loci were also obtained. In comparison to t he Japanese samples, three samples from the Kamchatka Peninsula had two to three times the level of variation; and a sample from Iturup Island (Kuril Island archipelago) was slightly more variable. Although the anadromous soc keye salmon were originally planted from Iturup Island to Lake Shikotsu, a close genetic affinity was not indicated. These seven samples of O. nerka w ere compared with representative samples previously studied in North Americ a using five polymorphic loci. Two large groups of samples were indicated i n multilocus analyses: 1) a cluster of the seven Asian samples, one Alaskan sample, and one northern British Columbia sample: and 2) a group that incl uded a southern British Columbia sample (Fraser River). and samples from th e Columbia River and Washington. We discuss these findings in light of main taining viable populations of both forms of O. nerka.