Peculiarities of the current structural and functional organization of the commercial ichthyocenosis of Kamianske Reservoir

Purpose. Based on the analysis of the results of field studies in the reservoir, to determine the primary data of the main commercial fish species (coefficients of fishing and natural mortality, recruitment, allowable level of elimination, catch biomass ratio) in order to assess stocks and allowable harvest volumes. To assess the commercial use of aquatic bioresources of Kamianske Reservoir. Methodology. The initial data for assessing the stocks and volumes of allowable harvest of aquatic biological resources are the results of field studies conducted on Kamianske Reservoir in the spring (March) and summer (June-July) periods of 2021 and 2023-2024. Ichthyological material was collected from catches of gill nets with mesh sizes a=38, 40, 45, 50, 60, 75, 90, 100, 120 mm, the total amount of fishing effort studied was 1167 net days, of which 16332 fish specimens were mass measured, 1165 specimens were collected for biological analysis of the main commercial species. Findings. The study showed that the current ichthyofauna of Kamianske Reservoir includes 41 fish species (including 19 commercial ones), which belong to 8 families. The main objects of fishing, which provide up to 80% of the total catch, are Prussian carp (Carassius gibelio Bloch, 1782), bream (Abramis brama Linnaeus, 1758), roach (Rutilus rutilus Linnaeus, 1758) and silver bream (Blicca bjoerkna Linnaeus, 1758). The trend towards an increase in commercial catches in Kamianske Reservoir, which was observed during 2010-19, has been observed to a lesser extent in recent years. In 2020, the catch decreased to 1.8 thousand tons, mainly due to Prussian carp (38.4%), secondary small-sized species (18.4%) and bream (16.2%). In 2023-2024, the catch again increased to the maximum level for the entire period of fishery exploitation of Kamianske Reservoir and amounted to 2.5 thousand tons. The main species that caused the increase in catches were bream (26.8%), roach (16.2%), silver bream (11.3%) and pikeperch (7.6%). Today, Kamianske Reservoir has a commercial stock of the main species at the level of 200 kg/ha, which ensures the possibility of its effective fishery exploitation. The main principles of regulating fishing in Kamianske Reservoir should be to reduce the fishing pressure on younger age groups and stimulate the catch of species whose stocks are not fully utilized, including through the organization of specialized fishing. Originality. A comprehensive analysis of the current structural and functional organization of the dominant complex of the commercial ichthyocenosis of Kamianske Reservoir was conducted and original data were obtained on parameters that characterize the processes of formation and exploitation of the fishery base within the framework of scientific support for the stable state of aquatic bioresources of national importance. Practical Value. The study materials were used to improve the existing scheme of fishery use of inland water bodies of Ukraine of national importance when implementing special use of aquatic biological resources. Keywords: aquatic bioresources, catch structure, mortality, commercial stock.