On the methodology of the Siberian sturgeon replacement brood stock formation population of the Yenisei river in the Krasnoyarsk region

The purpose of the study is to analyze the conditions for the formation of the replacement brood stock of the Siberian sturgeon Acipenser baerii Brandt in OOO Maltat (limited liability company), the Balakhtinsky District, the Krasnoyarsk Region. Tasks are analysis of the conditions of keeping and feeding fish. The object of the study is the replacement brood stock of the Siberian sturgeon of the Yenisei population of 2015-2017 birth in the amount of 439 cohorts. The water flow rate was set in accordance with the optimal oxygen content (8-10 mg/l) with a complete change of water in the pools every 25-30 min. The content of oxygen dissolved in water was measured with a Horiba LAQUA thermooximeter. The size of the fish was determined using a measuring board. Sex determination and assessment of the degree of maturity of the gonads in fish were carried out using an AcuVista VT98c ultrasound scanner, as well as by biopsy, starting from the age of 4 years and older. The fish were fed with extruded feed from Alltech coppens, Aller Aqua, Le Gouessant with the size of feed particles corresponding to the age of the fish. Juveniles weighing up to 100 g were sorted every 30-40 days. Once every 10 days, a sample of 50 specimens selected by random sampling was determined. During sorting, the juveniles were evaluated for health and conformation. After evaluation, up to 25 % of individuals were culled from the replacement brood stock. When keeping the replacement brood stock in the conditions of closed water supply systems of the fish farm, the following conditions are observed: stocking density for each size (age) group of the Siberian sturgeon, sorting and culling, feeding regimen. When the Siberian sturgeon is kept under controlled conditions, the duration of spawning intervals can be controlled, and they can be reduced to 1-2 years due to intensive feeding with high-quality feed, the temperature regime of the aquatic environment is 20-24 °C.