Influence of hydrochemical parameters on the species diversity of the fish fauna of small rivers in the Saratov region

The results of our monitoring of small rivers in the Saratov region (tributaries of the Volgograd reservoir) are presented. Hydrochemical and organoleptic analysis of water quality was carried out. The species composition of the ichthyofauna of water bodies has been investigated. Factors affecting the chemical composition and organoleptic parameters of small river water are shown, namely: the degree of economic development of the river valley and geomorphological characteristics. An increase in the degree of pollution (eutrophication) of the small tributaries of the Volgograd reservoir negatively affects the ichthyofauna of the reservoirs by reducing the numbers of the most water-demanding fish species (stenobionts) with their subsequent disappearance and, as a result, the reservoir passes from one fishery type to another one.