MOLLUSKS OF THE ARAL SEA

Based on literature data and studies carried out by the authors for more than 30 years, an analysis of the mollusk fauna of the Aral Sea is made. The paper considers and clarifies the species composition of mollusks that lived in the sea during the Holocene. The main reason for changes in the species composition of this group is shown to have been a decrease or increase in the salinity of the environment associated with changes in sea level. Long-term changes in the salinity of water, in our opinion, could have become the main reason for the poverty of the mollusk fauna of the Aral Sea. We assume that the transfer of juvenile mollusks by birds might have played important roles in the replenishment of the fauna with new species. This is probably true for mollusks of the family Cardiidae and Ecrobia grimmi. Another source of replenishment of the fauna of the Aral Sea must have been due to species inhabiting the rivers flowing into the Aral and the surrounding lakes. The article discusses in detail the process of faunal changes during the last regression of the sea. The availability of data on the salinity at which the mollusks became extinct makes possible a retrospective evaluation of the estimates of salinity boundaries for the existence of the same species obtained by different methods. The future of the fauna of the mollusks of the Aral Sea is considered in the implementation of different scenarios of sea rehabilitation.