REHABILITATION OF RIVER ECOSYSTEMS IN UKRAINE IN LIGHT OF IMPLEMENTING GLOBAL NATURE CONSERVATION STRATEGIES

Abstract

Fish products make up a third of the global balance of protein supply to the population, including freshwater ecosystems that supply about 20% of fish products. At the end of the 1980s, 12 crews were working in the surface waters of the Western Polissia of Ukraine to catch aboriginal species of fish. Since that time, as a result of draining swamps, regulation and straightening of riverbeds, overfishing, fishing crews from industrial fishing have disappeared, species diversity and productivity of such fish species as moray eel, bream, whitefish have decreased, golden crucian carp, pike, zander are in danger of disappearing, misgurnus, common nase. Complete sterilization of the Horyn and Styr riverbeds was carried out in past years by the emergency discharges of wastewater from the Ostrog, Dubnо and Horokhiv sugar factories. As a result of the siltation of the river-lake network by solid runoff and the formation of hydrogen sulfide zones at the boundary of the water environment and bottom sediments, the reproductive function of surface waters has decreased. There is an overloading of anthropogenic impurities over the natural ecological capacity of the river-lake network, as a result of the accumulation of impurities there is a change in successions and a change in the composition of hydrobionts, including the higher link of the trophic chain – aboriginal ichthyofauna. Due to the violation of the stability of the aquatic environment, the vulnerability of the ecosystem increases, which leads to the formation of crisis situations and the formation of a new stage of successional changes in the composition of hydrobionts. In order to preserve the aboriginal ichthyofauna and increase the sustainability of ecosystems, it is necessary to implement the global strategy for nature protection, in particular, the preservation of natural localities of the reproduction of the species diversity of the aboriginal ichthyofauna and fish productivity, and the improvement of water quality.