Distribution
Eurasia: Caspian, Black, Marmara and Baltic Sea basins (Sweden and Finland north to 63?N), North Sea basin from Elbe to Ems drainages. In Annatolia: in Marmara basin, south to Great Menderes and Lake Egridir and east to Kizilirmak drainage. Absent between Kizilirmak and ?oruh drainages. Extirpated in Crimea. Introduced in Rhine.