THE STATE OF ICHTHYOFAUNA IN THE BAY OF THE KIEV RESERVOIR EXPLOITED UNDER THE REGIME OF THE COMMODITY FISH FARM

Purpose. Assessment of the number, stock, and major biological indices of the representatives of commercial ichthyofauna in the liman commodity fish farm created on the Kуiv reservoir. Methodology. The work is based on the ichthyologic material obtained from gill net catches with mesh size of 30-120 mm during the summer period of 2013. Data collection and processing were performed according to generally accepted methods. In total, catches of 169 net-days of control nets were analyzed, of which 3426 fish were collected. Quantitative parameters were assessed based on empirical relationships «number – catch-per-unit-effort of gill nets». Findings. Fifteen representatives of commercial ichthyofauna were observed in the bay, which is a cut-off part of the Kуiv reservoir. The majority in small mesh size nets were silver bream Blicca bjoerkna (45.5% in number) and Prussian carp Carassius gibelio (24.6%). In large mesh size nets, 65.8% of catches in number and 86.1% by weight composed the introduced species – silver (Hypophthalmichthys molitrix), bighead (Aristichthys nobilis), and common carps (Cyprinus carpio). The native fish fauna of the bay was characterized by sufficiently high portion of commercially valuable fish species that indicates on a possibility for organizing an intensive harvest of the formed stock of the introduced species with high degree of selectivity. Length-weight indices of major commercial species are on the level, which is sufficient for normal fish productivity. Total commercial stocks of native ichthyofauna in the liman is 146 kg/ha that is three times higher than this value for the Kiev reservoir. Originality. For the first time, we performed a complex assessment of the ichthyofauna in the bay of a large reservoir, which for a long time has been used for stocking and intensive fish harvest. Practical value. Sound fish ranching has been shown to provide the stability of structural functional indices of the native ichthyofauna that forms favorable prerequisites (in the nature conservation aspect) for increasing the role of inland water bodies in the commodity fish production