The effect of environmental conditions of some lakes of the city of Kiev on ichthyofauna condition

Purpose. To study the ecological conditions of fish habitats and changes in species compositions of the ichthyofauna of lakes in the city of Kiev based on the effects of different degrees of the pollution of water bodies. Methodology. The paper presents the results of the determination of water hydrochemical composition in some lakes of the city of Kiev and the structure of their ichthyofauna. The collection and processing of ichthyological material was carried in accordance with generally accepted methods. Findings. The concentration of biogenic compounds, in particular phosphorus, phosphates, nitrites and ammonium, the concentration of oil products in water of some lakes of the city Kiev were investigated. The study results show that the highest concentration of oil products and nutrients was observed in the Lake Luhove, In particular, the concentration of oil products in water of the Lake Luhove was 0.020-0.206 mg/dm3, the Lake Kirilivske - 0.023-0.117 mg/dm3, the Lake Babyne 0.0007-0.0520 mg/dm3. This is confirmed by the fact that the Lake Luhove experiences a significant impact of pollutants from surrounding areas. It was found that the magnitude of the studied parameters varied significantly in different seasons of the year and in different parts of the studied lakes. This indicates the dependence of these parameters on natural, anthropogenic and hydrological factors, which differ in different parts of the water body and different seasons. The ecological state of the studied lakes significantly affects fish species composition and its structure. The Lake Kirilivske, despite being under moderate anthropogenic pressure, has relatively satisfactory environmental conditions. This is indicated by the greatest species richness of ichthyofauna compared to other studied lakes. The largest number of fish species was recorded in the Lake Kirilivske (27), in the Lake Babyne - 23 species, in the lake Luhove - 10 species. The consequence of intense pollution of the Lake Luhove is a significant decrease in the species composition of its ichthyofauna, in particular in the bottom complex. This indicates the greatest environmental pressure on this lake from toxic substances from adjacent territories. The performed studies showed that the Lake Babyne, due to its isolation from the urbanized part of the city, had the highest water quality at different times of the year. In addition, sound succession processes occur in this water body. Originality. The characteristics of the ichthyofauna of some lakes of the city of Kyiv were presented for the first time depending on the hydro-ecological conditions and season. The negative effects of anthropogenic pollution on the structure of the ichthyofauna of these lakes were shown. Practical value. The results obtained are necessary for determining the patterns of changes in the species composition and its structure under conditions of moderate and excessive anthropogenic pollution of water bodies. This allows further predicting the increased effect of anthropogenic pollution on the ichthyofauna of relatively clean water bodies.