Some results of winter keeping of paddlefish young-of-the-year (Polyodon spathula (Walbaum, 1792)) in ponds of the Forest-Steppe and Polesye of Ukraine

Purpose. Assessing the results of winter keeping of paddlefish young-of-the-year in ponds of the Forest-steppe and Polesye of Ukraine. Methodology. The study was carried out using 0.05-1.0 ha ponds intended for winter keeping of carps. The stocking density of paddlefish young-of-the-year with an average weight of 94.2-147.2 g in wintering ponds was 4.10-16.63 thousand fish/ha. The study of the physicochemical parameters of the aquatic environment was carried out according to the methods generally accepted in hydrochemistry and fish farming. The main piscicultural-biological parameters during the wintering period of fish were assessed using methods commonly used in ichthyology and fish farming according to the level of survival and body weight loss of paddlefish. Findings. The environmental conditions in the ponds during most of the wintering period of fish met the biological requirements of the studied object of cultivation. The water temperature varied within 0.9-6.50C. The dissolved oxygen content in water did not fall below 3.6-3.8 mgO2/dm3 and was mainly at the level of 3.9-7.9 3.9-7.2 mgO2/dm3. Other hydrochemical parameters were within acceptable values ​​for wintering fish in pond conditions. As a result, the survival rate of paddlefish young-of-the-year during the wintering period was 81.5-89.7%. The body weight loss of fish during the winter keeping was on average in the range of 6.41-8.17%. A conclusion was made on the need to conduct additional studies of physiological and biochemical parameters of paddlefish during the wintering period. Originality. New data were obtained on the peculiarities of wintering of paddlefish seeds in ponds of the Forest-steppe and Polesye of Ukraine. Practical value. The study results are part of the database for the development of improved technologies for sturgeon breeding in Ukraine.