Distribution
Europe and Asia: large rivers draining to Black, Azov, Caspian and Aral Seas. Introduced or native to Northern Dvina drainage (White Sea basin) where it is presently spreading from warmer upper reaches (Vychegda system) northward. Introduced in River Volkhov (a tributary of Lake Ladoga), in Rhine in 1995 and invasive in Vistula drainage, coming from Black Sea basin through Prypet-Bug canal (connecting Dniepr and Vistula drainages).