Reproductive indicators of sterlet and Siberian sturgeon when grown in aquaculture and in natural reservoirs

Abstract

The biological indicators and results of spawning of sterlet and Siberian sturgeon on the example of fish farms with different industrial technologies of fish cultivation and different amounts of heat during the year are analyzed. The comparison of reproductive indicators of these species of different populations from natural reservoirs is carried out. It is shown that in the conditions of warm-water farms, producers of sterlet and Siberian sturgeon matured at a higher mass, mature oocytes reached larger sizes, but such indicators as the yield of eggs from the mass of the female and relative fertility decreased. The working fertility of sterlet depended on body weight, and, accordingly, was higher in fish grown in the conditions of the plant (43,000 thousand pieces). Sterlet of Siberian populations (Irtysh and Ob) matured at a lower weight than the Volga, and was distinguished by a large yield of caviar from body weight — up to 17%. In the Ob sturgeon in industrial conditions, with a larger mass of females, the working fecundity was less than in natural reservoirs. Wild sturgeon from the Lena River, maturing at a lower mass among all populations of Siberian sturgeon, was characterized by high relative fertility (12,8 thousand pieces/kg) compared with the domesticated form (5,4–6,0 thousand pieces/kg). When growing these species in aquaculture, the ratio of growth and fertility indicators changes markedly. In natural reservoirs, the maturation of germ cells and reproduction of sturgeon fish is largely determined by both the amount of heat and seasonal temperature changes, which ensures the synchronous development of gametes and the best reproductive performance.