Morphological and Genetic Heterogeneity of Sockeye Salmon Oncorhynchus nerka (Salmonidae) of Large Lake–River Systems in Eastern and Western Kamchatka

Abstract

The morphological and genetic heterogeneity of sockeye salmon Oncorhynchus nerka (from both the mixed samples and the samples collected in different periods of its mass migration) catched in the mouths of the rivers of west (Ozernaya, Bolshaya, and Palana rivers) and east (Kamchatka River) costs of Kamchatka Peninsula has been analyzed. The stocks of the sockeye salmon inhabiting these river basins (including tributaries and lakes) are the largest in Asia. According to the assessment of the biological parameters and the allele frequencies at 45 loci of single-nucleotide polymorphism at the DNA level, no periodicity in the mass-spawning migration of the sockeye salmon in the rivers of the Kamchatka Peninsula’s western coast was revealed. The analysis of the sockeye salmon’s mixed samples collected from the western Kamchatka Peninsula rivers allowed identifying a group of fishes in the sample taken from the Bolshaya River that was ascertained to the lake form. With respect to the Ozernaya and Palana river samples, the phenotypic and genetic heterogeneity was not revealed. The heterogeneity revealed in the fish sample taken from the Kamchatka River’s mouth can point to a complex spatial-genetic structure of the sockeye salmon in the basin of this lake–river system. The differences between the samples collected during the mass migration through the river’s mainstream indicate the successive approach of fishes to the mouth by the local groups that spawn in the different parts of the river basin.