Current state of ichthiocenosis, species composition and fish populations in small river basins from Pripyatske Polissiya of Ukraine — ways of rehabilitation and restoration

Purpose. To study ichthyocenosis, species composition and current state of fish populations in small river basins from Pripyatske Polissiya of Ukraine, to propose the ways of their rehabilitation and restoration. Methodology. The study analysed data for last 60 years on the results of monitoring catches of fish wintering grounds of the first-order tributaries of the Pripyat River — right-bank rivers (rivers Slovechna, Sluch, Tina), as well as more than 300 flood plain lakes of the Desna River. Fish were caught by expeditionary methods using boats, seines and gill nets before ice formation in November-December. Methods generally accepted in ichthyology and ecology as well as surveys of anglers were used. Findings. The study showed the crisis state of the Upper Dnipro region, which was confirmed by the data on a significant decrease in fish productivity. The reasons for this are: non-observance of the basin approach in nature management, ineffective nature conservation measures, lack of measures for the rehabilitation of "natural localities" for the reproduction of native ichthyofauna. It should be noted that the creation of National Reserves and NaturalParks (Shatskyi, Pripyat-Stokhid, Rovenskyi, Polesskyi, Menskyi, etc.) did not significantly affect the general state of the problem, and rather has a declarative meaning. Since, although they still have some places with good reproduction conditions for native flora, fauna and valuable natural landscapes, however, this does not affect the general ecological situation in the river network. This is due to the fact that the surface runoff from territories without destructive human impact, which form the hydrochemical regime, is a fraction of a percent of the total amount. Accordingly, the following is observed: shallowing of river channels, smoothing of the bottom, siltation of wintering grounds, decrease in breeding stock number, degradation of spawning grounds and a lack of artificial stocking measures. This leads to a 10-fold decrease in fish catches in small rivers from Pripyatske Polissiya of Ukraine over the past 20 years. Originality. The study examines the problem of the relationship between the accessary river network and the fish productivity of rivers, including the Kуiv (receiving the flow of the DniprоRiver) and the upper reaches of the Kaniv (receiving the flow of the DesnaRiver) reservoirs. It outlines their role in the functioning of the trilateral natural complex located on the territory of Ukraine, Belarus and Poland. The possibility of creating the ichthyo-ecological reserve "Verhniy Dnipro on the territory of Ukraine on the base of existing protected areas within the Pripyat and Desnyansky hydroecological corridors is analysed. Practical Value. It has been proved that the creation of the "Verhniy Dnipro" will allow not only creating a stable base for the natural reproduction of native ichthyofauna in the upper reaches of the Dnipro reservoir cascade but providing high-quality water to the population of Kyiv and the Kyiv region. The concept of rehabilitation of reproduction and conservation of biodiversity of native ichthyofauna in the river network is proposed to maintain the stability of the biosphere, the implementation of which requires little funds.