Coastal and freshwater pikeperch (Sander lucioperca) populations differ genetically in the Baltic Sea basin

Microsatellite DNA based analysis of the pattern of genetic diversity among three coastal and five freshwater populations of pikeperch Sander lucioperca in the northern part of the Baltic Sea drainage basin indicated marked genetic differentiation between the coastal and lake populations. The Fst between these population groups was as high as 0.25 and Rst=0.32. In general, the lake populations showed higher genetic diversity than the coastal ones. In terms of genetic distance, the three coastal populations (Vanhankaupunginlahti, Västanfjärd and Taivassalo) grouped tightly together. The freshwater samples formed a looser group, in which the northern Lake Kemijärvi showed greater distance from the southern lakes than these did from each other. The two lake populations originally established through stockings (Lakes Painio and Averia) grouped near to their source population of Lake Lohjanjärvi and their diversity level was nearly the same. Safeguarding the unique Baltic coastal populations of S. lucioperca against gene flow from increasing hatchery releases using freshwater S. lucioperca should be a high management priority.Peer reviewe