Influence of the Reduction of the Flow of the Foothill Izdrevaya River (the Basin of the Upper Ob) on the Fish Species Composition and Distribution

The results of the survey of the small foothill river of the Salair mountain ridge (Upper Ob basin) reflect the correlation of the species richness, species diversity, and density of the fish community with the hydrological regime of the watercourse in areas from the source to the mouth. The features of fish distribution in the river channel have been assessed during a decrease in the flow volume. Water withdrawal for irrigating agricultural lands leads to a decrease in the abundance and species richness of representatives of the boreal plain faunal fish assemblage and, at the same time, to an increase in the proportion of representatives of the Arctic assemblage in the shoaled areas of the lower reaches of the river.