A New Species of Pacific Salmon—Rosy Salmon Oncorhynchus gorbuschka sp. nova: Description and Genesis of the Taxon

The division of the Pacific salmon species Oncorhynchus gorbuscha sensu lato (Walbaum) into two closely related cryptic species inhabiting the same areas of the North Pacific is proposed based on long-term complex studies of intraspecific morphological and genetic differentiation for this species. The new species Oncorhynchus gorbuschka sp. nova Glubokovsky et Zhivotovsky (rosy salmon) is described in detail. The most striking ecological difference between this species and pink salmon Oncorhynchus gorbuscha sensu stricto (Walbaum) is that rosy salmon spawn only in odd years, whereas pink salmon spawn in even years. Thus, these two species form two reproductively isolated broodlines throughout their range. Differences between them can also be found in demographic patterns, morphological traits, protein and DNA markers, and full-genome profiles. Presumably, both of these species are relatively young, having evolutionarily diverged from each other during sympatric allochronic evolution resulting in a single age class in both populations. As a result, all sexually mature individuals of each broodline spawn at exactly 2 years of age and die soon after spawning (although rare exceptions are possible). The separation of these two species of Pacific salmon requires their separate consideration in fundamental and applied studies, fisheries and regulation of fisheries, protection, and artificial reproduction.