Scientific publications

By using polymerase chain reaction and restriction fragment length polymorphism of mitochondrial DNA, we studied the maternal lineages of brown trout populations in Eastern Fennoscandia, in the Baltic Sea, White Sea and Barents Sea basins. The distribution of haplotypes reflects the glacial and postglacial history of fish fauna. The hypothetical postglacial contact zone in Kovda river system in Kuusamo-Paanajarvi area was studied in detail. There, one maternal lineage arrived during the high phase of White Sea Ice Lake (9500 BP). Lacustrine population in Paanajarvi, and several relict brook trout stocks >170 m above the present sea level represent the earliest period, which is marked by a unique mitochondrial haplotype, endemic for lacustrine populations in Russian Karelia. Western upwaters of the Kovda river system were colonized during the high Ancylus lake phase of the Baltic Sea. The lake Kitkajarvi was formed on the edge of retreating ice 9400-9500 BP, and it was colonized from the Baltic basin. About 8400 BP, due to the land uplift, the lake tilted eastwards and became isolated from the Baltic basin. Fish immigration from Paanajarvi was prevented by a seven meter waterfall. The lacustrine trout stock of the Lake Kitka descends to the river Kitka for spawning above the waterfall, but the Baltic mitochondrial haplotypes have not colonized Lake Paanajarvi. The anadromous trout populations in the Kola Peninsula differ clearly from the Karelian lacustrine populations, due to colonization from other refugium. The Lake Onega and Lake Ladoga trouts share haplotype frequencies related but not identical with Northern Baltic landlocked populations, supporting the hypothesis that they represent the first colonization wave in the Baltic Basin. The trout phylogeography further emphasize the importance of White Sea – Baltic Sea watershed as a major divide of aquatic fauna, confirmed earlier by the community of grayling, salmon, and the parasite Gyrodactylus salaris.