Caspian Sea Basin in Volga River Basin (Volga, Kama, Vyatka, Sura, Penza, and Oka rivers); Ural River Basin (Ural River); and Terek River Basin (Terek River) (Ref 89241). Endemic to Caspian Sea; earlier migrated to the Volga, Ural, Terek and other rivers (Ref. 26334). This has been translocated to different areas within the country however, it failed to establish self-sustaining populations (Ref. 45022). Construction projects along the rivers had a negative impact on this species. After construction of the Volvograd Dam, this species has not penetrated upstream and rare individuals occur in the Volvograd and Saratov reservoirs. Although formerly a commercial species, it has now become rare. Also Ref. 12275. EurRus