Rioni River
Formerly abundant in the Black, Aral and Caspian seas, its range is now primarily limited to the Ural River (in Russia and Kazakhstan), with possible relict populations in the Rioni River in Georgia and the Safid Rud in Iran. One of the most established populations is one in Lake Balkhash in Kazakhstan, well outside its natural range, where they were introduced in the 1960s for commercial purposes. A decline in the abundance of "Acipenser nudiventris" has been reported due to overfishing and damming, which have led to limitations placed on fishing for bastard sturgeon in areas such as the Ural River. In order to alleviate concerns with rapidly decreasing "Acipenser nudiventris", an effort was made to raise these fish in captivity before releasing them back into rivers they once inhabited.