Distribution of snail from the genus Gyraulus (Gastropoda, Planorbidae) in the middle tributary of the Saratov reservoir

Background. The Volga basin has been studied unevenly from an ecological point of view. The region of the Upper Volga can be rightly considered the best studied area. While the Lower Volga remains less investigated despite its significant influence on the complex of interrelated social, economic and ecological problems. The most informative assessment for the state of aquatic ecosystems is the state of macrozoobenthos which has various advantages over other approaches, first of all, consisting in species diversity and structure of bottom communities. Freshwater mollusks are one of their numerous groups. In the Volga basin there are representatives of two classes: Gastropoda and Bivalvia. Therefore, the aim of the work is to reveal the peculiarities of Gyraulus albus distribution in the Samara River and to establish quantitative characteristics in different sections with different ecological conditions.