The Ural River Sturgeons: Population Dynamics, Catch, Reasons for Decline and Restoration Strategies

Abstract

The Ural river, the third longest river in Europe, has the only remaining spawning habitats in the entire Caspian basin for all sturgeon species. Unlike other large European rivers the river’s ecosystem has not been altered and the natural hydrological regime is still intact. The Ural sturgeon yield-to-fishery relative to river discharge was the highest in the Caspian Sea till recently. The environmental conditions to secure natural reproduction are still satisfactory for successful sturgeon reproduction. However, nowadays the catch in all regional sturgeon species is negligible. The Ural sturgeon population dynamics are analyzed along with some anthropogenic and natural factors affecting them. It is argued that legal overfishing (including all legal means of fish removal), based upon (a) faulty estimations of sturgeon stock and catch limits and (b) inappropriate fishery policies are the principal reasons for the stock decline in the Ural. The maintenance of the natural reproduction in the Ural is considered to be the primary strategy for the stock replenishment. If used at all, artificial propagation should be used only as an additional secondary option exclusively at the historical sturgeon habitats upstream the Ural river and not in the river delta, where the hatcheries are located now. Transboundary cooperation of basin countries with active international involvement is essential to prevent further deterioration of the situation.