Principal component analysis (PCA). (a) Results of the PCA of the Atlantic salmon populations from northwest Russia. Anadromous populations were represented by 2 groups: the Kola Peninsula and Karelian White Sea coast. Freshwater–by the groups of Lakes Ladoga and Onega (Baltic Sea Basin), and populations of the Western White Sea Basin: Kamennaya and Pisto. (b) Results of the PCA of the temporal replicates of the anadromous salmon populations of the Kola Peninsula (White Sea Basin).