Winter keeping Siberian sturgeon (Acipenser baeri Brandt) with nutritional deprivation in closed water supply installations

The purpose of the study is to assess the organization of winter maintenance of Siberian sturgeon spawners with food deprivation. Tasks - to establish the optimal feeding temperature at various stages of maturity, the duration of keeping various groups of fish at low temperatures under RAS conditions; to propose a scheme for transferring fish to forced starvation. Technological processes during the winter keeping (wintering) of the Siberian sturgeon brood stock in the fish farm LLC Maltat were studied. The brood stocks of the Siberian sturgeon of the Yenisei population of 2015-2017of birth were studied. The total number of males and females involved in reproduction was 439 specimens. The decrease in temperature during wintering of mature females was carried out gradually with a gradient of 0.7-1.5 °C per day, for males and immature individuals maturing for the first time - 2-3 °C. The transfer of males to keeping under cyclic temperature conditions under RAS conditions was carried out at the age of 2-3 years, females - at 3 years. The temperature interval for keeping fish during wintering is 4-5 °C, while a short-term increase or decrease in temperature in the range of 3-10 °C is allowed. The wintering stage was accompanied by food deprivation (starvation). Fish with a fatness coefficient of more than 0.5 were subjected to starvation. The duration of wintering for immature females was 40-80 days; for males and females that have stage IV of maturity to obtain raw caviar, this indicator was 45-180 days, with an optimal 70 days. In fish used for reproduction, the wintering period is 90-180 days. Under the specified conditions of winter keeping, the age of the first maturation and the time of transfer to the cyclic temperature regime of males in the repair and broodstock in the conditions of the fish farm of LLC Maltat is 4-5 years, females - 5-7 years.