ВЛИЯНИЕ ТЕМПЕРАТУРЫ В ЭМБРИОГЕНЕЗЕ НА РЫБОВОДНО-БИОЛОГИЧЕСКИЕ ПОКАЗАТЕЛИ МОЛОДИ ГИБРИДА БЕСТЕРА

Abstract

The article focuses on the influence of different temperature parameters during incubation of bester hybrid Acipenser ruthenus (Linnaeus, 1758) × ( Huso huso (Linnaeus, 1758) × × Acipenser ruthenus (Linnaeus, 1758)) of the Aksay breed of the fourth generation (F4) on the abnormalities in embryogenesis and on the rate of growth and survival of the hybrid juveniles in recirculating aquaculture systems. As a result of experimental work, it has been proved that the optimum incubation temperature for bester roe is 16°C, and the fastest rate of weight growth is observed in bester juveniles bred from eggs incubated at a water temperature 18-20°C. A distinctive feature of the incubation of eggs at 18-20°C is elimination of a large number of fertilized eggs (25%) even at the early stages of development. Also, at lower water temperature (8 and 12°C), the highest percentage of embryo anomalies at the hatching stage has been observed. The lowest survival rate had juveniles from eggs, incubation of which took place at a temperature of 8°C (14-32%). The highest survival rate from one-day prelarva to fry with average weight of 1 g was observed in bester species grown from eggs which were incubated at a temperature of 12-13°C (38-90%). It is shown that the temperature difference of 1-2°C during cultivation affects juveniles' weight. Data are given on the effect of growing density on the survival rates and weight of juveniles. The stocking density of bester at the stage of larvae that switched to active feeding to the juvenile with a mass of 1 g should not exceed 2-3 kg/m3 in order to guarantee optimal growth rates, survival rate, and to maximize the use of tanks volumes. It has been stated that the lower the temperature of water during the incubation of eggs, the slower the fish grows in the future. However, this effect is leveled in species by the age of 250-300 days, if the optimal growing densities are non-compliance.