How have Volga River dams disrupted sturgeon migration and breeding?

The construction of dams and reservoirs along the Volga River has significantly disrupted the life cycles of anadromous fish, most notably the beluga sturgeon.1

These structures have blocked or severely restricted the ability of sturgeon to migrate from the Caspian Sea into the river to reach their natural spawning grounds. By preventing access to these essential breeding areas and fundamentally altering the river's habitat, the dams have contributed to the deterioration of major fisheries.1

In addition to physical barriers, the impoundment and diversion of water for irrigation have reduced the river's discharge, further impacting the environment. To mitigate these adverse ecological consequences, significant efforts have been made to support sturgeon populations, with approximately three-fifths of Caspian sturgeon now being bred artificially rather than in their natural spawning grounds.1