Evolutionary and Ecological Aspects of the Population Structure Formation of Sockeye Salmon Oncorhynchus nerka (Salmonidae) in Western Kamchatka

— The results of previous studies on the population structure of the sockeye salmon Oncorhynchus nerka of Western Kamchatka are revised based on the analysis of the variability of 45 single nucleotide polymorphism loci using both own data (seven samples from the water bodies of the western coast of the Kamchatka peninsula) and the data obtained by other researchers (seven samples from the basin of Lake Kurilskoye and one sample from the Bystraya River, basin of the Bolshaya River). All materials were re-analyzed to clarify the existing ideas about the origin and formation of the populations of sockeye salmon of the Western Kamchatka complex, as well as to reconstruct the historical and modern demographic and genetic processes that occur in these populations. According to the results of genetic differentiation tests, principal component analysis, and discriminant analysis of the principal components the sample set of lake sockeye salmon from the Ozernaya River (reproduction in the basin of Lake Kurilskoye) and Plotnikova River (predominantly the downstream migrants from Lake Nachikinskoye) differed the most from the other samples, represented mainly by river sockeye salmon. The results of the principal component analysis and the topology of the phylogenetic network for the sample sets from the basin of Lake Kurilskoye revealed their division in accordance with the periods of spawning grounds filling and with the geographical variability of the spawning periods of sockeye salmon in the lake basin.