Состав фауны моллюсков Азовского моря как функция его соленостного режима

Abstract

The impoverishment of the Mediterranean-origin complex inhabiting the Black-Azov seas Basin is caused by the salinity gradient. Based on supplemented faunal data, the index of reduction of the Mediterranean molluscs species number under the transition from the Black Sea to the Sea of Azov is calculated. The index is 2.5 for Gastropoda and 3.5 for Bivalvia: on the average for mollusks, it equals 2.8. The index for specific taxons was utilized as a degree of their relative osmoregulation ability. On the basis of these data, the long-term taxonomic prognosis of the ''pontization'' process of the Sea of Azov, i.e. the replenishment of its fauna by species which occur in the Black Sea, is formulated.