Genetic diversity of salmonid fishes in the eastern part of the Onega Peninsula, Northern European Russia

The Onega Peninsula in the White Sea, north-western Russia, is a habitat for ecologically and economically significant salmonid species, i.e. Atlantic salmon Salmo salar Linnaeus, 1758 and brown trout S. trutta Linnaeus, 1758 (Salmoninae). However, these populations are currently understudied in terms of molecular approach. In this work, we assessed the genetic diversity and differentiation of S. salar and S. trutta from the eastern part of the Onega Peninsula based on mitochondrial (COI and cytb) and nuclear (RAG1) markers. We also traced a phylogeographic pattern of these species. Populations of brown trout in the studied watercourses mainly share low haplotype and nucleotide diversity, with the exception of the moderate values in the Gosdarea River. In turn, Atlantic salmon in the Ust’-Yaren’ga River has higher genetic diversity than brown trout. Our study reveals great importance of conservation measures and monitoring, as well as parasite pressure control, especially for brown trout, in the eastern part of the Onega Peninsula.