Europe: In the Baltic Sea: Swedish coast (including Bothnian Gulf, not in Gotland); in southern Baltic, extending from River Schlei to Gulf of Finland. Southeastern North Sea Basin: Ems, Weser and Elbe drainages and small rivers of Schleswig-Holstein and Denmark. Landlocked in Lake Miedwie and other lakes in Poland, Lake V?ttern, V?nern, M?laren, Siljan (Sweden), Ladoga (Russia) and others. Introduced and transplanted in many drainages within its native range and outside westward to Rhine drainage. (Ref. 59043). Usually known as C. lavaretus in the Baltic Sea basin. North Sea population might represent a distinct species (Ref. 59043).