Productivity of nursery ponds under the complex exposure to their ecosystem

Purpose. To investigate the peculiarities of the formation of hydrochemical, hydrobiological regimes and to determine the fish productivity of nursery ponds under a complex exposure to their ecosystem. Methodology. The work was conducted according to generally accepted hydrochemical, hydrobiological and aquaculture methods. Findings. The article presents the results of the study on the productivity of nursery ponds when using a complex of intensification measures (fertilization with traditional fertilizers, application of chlorella paste, polyculture, and fish feeding). It was found that the main hydrochemical parameters during the rearing of cyprinid fingerlings were within the standard normal values ​​and were favorable for the development of prey organisms and the cultivation of fish seeds. Positive trends were obtained after the use of chlorella paste when growing juveniles of cyprinids in polyculture with different ratios of common carp and Chinese carps. The use of the chlorella paste in combination with other intensification measures in the experimental ponds created favorable conditions for the development of natural food supplies, growth and survival of cyprinid fingerlings. At the same time, the total fish productivity in the experimental ponds was 22.0-28.0% higher, and the feed costs were 1.1-1.3 times lower than in the control ponds. Originality. The peculiarities of the formation of hydrochemical and hydrobiological regimes have been investigated and the fish productivity of nursery ponds has been determined using cattle humus and chlorella pasta when growing young-of-the-year carp in polyculture with silver and bighead carp hybrids. Practical value. The obtained data can be used for developing practical recommendations regarding the optimization of the conditions for growing cyprinid seeds in polyculture using the chlorella pasta, increasing the efficiency of managing the state of aquatic ecosystems and their biological productivity.