Phylogeography of anadromous and non-anadromous Atlantic salmon (Salmo salar) from northern Europe

The phylogeography of north European anadromous and non-anadromous Atlantic salmon (Salmo salar) populations was investigated using 21 nuclear (microsatellites and allozymes) loci and mitochondrial DNA haplotypes. A neighbour-joining population tree revealed several statistically supported groupings that generally corresponded well with the sampling regions. A comparison of F-ST and R-ST estimates with a novel allele size permutation method suggested that at least two of the groups had diverged from each other already prior to the ice receding after the last ice age, thus suggesting that north European Atlantic salmon are derived from at least two separate refugia. We propose that the anadromous and non-anadromous salmon populations from the Baltic Sea basin most likely originate from a southeastern ice-lake refugium. The present day White and Barents Sea basins have probably been colonized from multiple refugia.