The Splendour and Misery of European Pink Salmon, Oncorhynchus gorbuscha: Abundant Odd Lineage vs. Depressed Even Lineage—Insights from cytb Gene Analysis

Pink salmon, Oncorhynchus gorbuscha, introduced to the White Sea and expanded throughout the West Arctic and Northern Atlantics, represents a noteworthy example of a successful marine species introduction that has significantly impacted the local fish community. In our study, we analysed mitochondrial cytochrome b sequences from 635 individuals, representing both odd-year (n = 411) and even-year (n = 224) spawning lineages. These samples were collected from rivers in the White, Barents, Kara, and Northern seas, as well as from source populations in the Pacific. Fifteen cytb haplotypes were identified in the odd-year spawning lineage and twenty-six in the even-year lineage, with only ten haplotypes found in both lineages. The results demonstrated significant genetic differences between the native Pacific populations and the introduced Arctic populations in the odd-year lineage. In contrast, no genetic differentiation was found in the even-year lineage. This study describes the current haplotypic structure of European pink salmon in the Russian Arctic and provides insights into the genetic consequences of the species’ introductions.