The zoocenosis of the Aral Sea: six decades of fast-paced change.

During the last six decades, the water level of the Aral Sea, once one of the largest lakes in the world, has experienced a major human-driven regression followed by significant changes in salinity. These fast-paced alterations were initiated by the diversion of two rivers-the Amu Darya and Syr Darya-key players in the regulation of the water balance of the Aral Sea. Consequently, biological modifications took place leading to severe changes of the zoocenosis. This paper reviews the changes that have affected communities of fish and aquatic invertebrates in the Aral Sea since the 1950s. The reported alterations in biodiversity not only represent a natural response to a decrease in water level and a subsequent increase in salinity but also effects of non-native species introduction. The future prospects for invertebrates and fish in the Aral Sea, assuming that initiated restoration work is continued, are also discussed in this paper.