Fishery assessment of brood Siberian sturgeon (Acipenser baerii Brandt, 1869) cultivated in floating cages at natural water temperature of the Forest Steppe of Ukraine

Purpose. To determine and evaluate the main fishery parameters in the process of artificial production of mature eggs from brood Siberian sturgeon grown in floating cages at natural water temperature of the Forest-Steppe of Ukraine. Methodology. The material for the study was 121 specimens of Siberian sturgeon females of various ages with body weights from 3.80 to 16.84 kg, which were cultivated in industrial-type farming conditions in a water body with a natural temperature regime for the Forest-Steppe zone Ukraine with the use of floating cage systems. Experiments on obtaining mature eggs were carried out under controlled water temperature during the period from January to April under the conditions of a recirculation aquaculture system. Hormonal stimulation for the maturation of sturgeon gonads was performed using natural cyprinid pituitary preparations. Determination of fishery indicators and study of environmental abiotic factors were carried out according to methods generally accepted in fish farming and hydrochemistry. Findings. The efficiency of maturation in brood fish of different groups varied between 57–100% at a water temperature of 14.0–15.5°C after the injection of a gonadotropic drug with a total dose from 2.5 to 4.5 mg/kg per fish weight. A total dose of the gonadotropic drug of 3.5 mg/kg per fish weight was found to be sufficient for the high efficiency of gonad maturation. The weight of mature eggs obtained from brood fish aged 8+ to 17+ varied on average from 0.54 to 2.12 kg. The average working fecundity and relative fecundity in females of different ages varied, respectively, within the range of 33.60-108.21 thousand eggs and 6.62-7.95 thousand eggss/kg of fish weight, with average values of the gonadosomatic index of 10.71-15.81%. Originality. The peculiarities of obtaining ovulated eggs and the main fishery parameters of brood Siberian sturgeon cultivated using the technology of intensive sturgeon aquaculture, which is not common in Ukraine, were studied. Practical value. The study results can be used for the development of modern methods of sturgeon aquaculture in the industrial farms conditions.