Data for the assement of beaver influence on fish assemblages of small steppe rivers

The data was collected on small steppe rivers of the Khoper River basin (tributary of the Don River) in and around of the State nature reserve “Privolzhskaya Lesostep” (Penza Region, Russia, N 52°48′58.4′′, E 44°27′40.4′′), in 2015-2016. It content abundance, density and biomass of fish, and abiotic parameters of river habitats - water area, amount of dissolved oxygen, pH, water temperature and water current velocity.