Bivalves of the Genus Dreissena of the Kuibyshev Reservoir

Based on long-term studies, modern data on populations of Dreissena bugensis and D. polymorpha in the water area of the Kuibyshev Reservoir are presented. It is shown that the basic quantitative parameters in all considered reaches of the reservoir, identified types of sediments and depths were formed by D. bugensis. In the consortia of dreissenids, 146 taxa of benthic invertebrates were identified, of which 26 taxa were alien species. The abundance in such communities was mainly formed by crustaceans, and the biomass, by mollusks. The analysis of seasonal dynamics showed a decrease in the quantitative parameters of D. bugensis from May to October, while for D. polymorpha, on the contrary, there was an increase by autumn. An analysis of the interannual dynamics has revealed an increase in the abundance of D. polymorpha and a decrease in D. bugensis in recent years.