Distribution
Europe: Baltic basin, lakes of upper Volga drainage (Seliger, Vseluga, Perejaslavskoe), some lakes of White sea basin and North Sea basin east of Elbe drainage. Anadromous in Gulf of Finland and marine in northernmost freshened part of Gulf of Bothnia; north to about 69? N in Lake Inari, northern Finland; lower Rhine (now extirpated). Frequently stocked in lakes and reservoirs in Germany and Poland. Appendix III of the Bern Convention (protected fauna).