Results of the experiments on artificial production of ovulated eggs from brood sterlet Acipenser ruthenus (Linnaeus) at non-traditional terms

Purpose. To study the peculiarities of the artificial production of ovulated eggs from brood sterlet at non ‐ traditional terms and to determine major productive parameters in experimental fish groups. Methodology . The object of the study were sterlet females of different ages with body weights 1.4–3.3 kg reared in the conditions of a farm of industrial type in a water body with natural temperature regime for the forest ‐ steppe zone of Ukraine. The experiment was performed under regulated water temperature regime during the period from January to March with the use of natural gonadotropic preparations for the stimulation of fish gonad maturity. A recirculating aquaculture system was used during the preparation of brood fish for the study. Determination of productive parameters and study of physical ‐ chemical factors of the environment were performed according to generally accepted methods. Findings. High efficiency of gonad maturation was observed in all experimental fish under water temperature of 14.0 ‐ 16.5 o C. Mean weights of sexual products obtained from brood fish in different experimental variants were 130–384 g. Mean working fecundities and relative working fecundities of sterlet females varied within 13.42–36.83 thousand eggs and 8.80–13.40 thousand eggs/kg of fish weight. General duration of fish maturation from the beginning of hormonal stimulation until the moment of the beginning of egg ovulation changed on average from 407.6 to 587.4 degree ‐ hours. Originality . The peculiarities of the production of mature eggs from sterlet females with the use of industrial reproduction of sturgeons, which is new for Ukrainian aquaculture, have been studied. Practical value. The study results can be useful for the development of advanced methods of sturgeon aquaculture in the conditions of industrial fish farms.