Europe: Black, Azov, Caspian and Aral Sea, ascending some rivers (Danube up to Bratislava, Volga up to Kazan, Ural up to Chkalov), unknown or very rare in others. On the verge of extinction in its natural range. Extirpated in Aral basin; nearly extirpated in Black Sea basin; only occasional records from Danube and lower Volga; only a very small population remaining in Rivers Ural (Russia, Kazakhstan) and Rioni (Georgia); no natural spawning population in Iran; established in Lake Balkhash where it forms a large population (Ref. 59043). Artificially propagated (Ref. 6866). International trade restricted (CITES II, since 1.4.98; CMS Appendix II).