STUDY Of HATCHERIES - BIOLOGICAL INDICES OF RUSSIAN STURGEON fry (<i>ACIPENSER GUELDENSTAEDTII</i> BRANDT, 1833), GROWN AT DIFFERENT DENSITIES of stocking
The effect of stocking density on the absolute and relative growth rates, survival rates, the mass (at the end of the experiment) of the Russian sturgeon ( Acipenser gueldenstaedtii Brandt, 1833) is examined. The studies were conducted at the research institute N 3 on the research station Teynguen for studying cold-resistant species of fish (Vietnam, Lam Dong Province). The tests to determine the stocking density, suitable for the cultivation of Russian sturgeon in the growth stage of the juveniles weighing 3-4 g to fry weighing 20-25 g, were carried out in 3 versions - 200, 400 and 600 individuals/m2. It is found that when the density of stocking was 200 birds/m2 the absolute fish growth rate was higher than the density of stocking 400 and 600 birds/m2. The relative growth rate and weight of the fish at the end of the experiment with stocking density of 200 individuals/m2 were also higher than in the stocking density of 600 individuals/m2. However, there were no statistically significant differences in these exponents of fish with stocking density of 400 individuals/m2 and fish with stocking density of 200 and 600 individuals/m2. The survival rates of fish with the stocking density of 200 and 400 individuals/m2 were higher than in fish from the reservoir with the stocking density of 600 individuals/m2. It is obvious, that the density of stocking of Russian sturgeon in transition from fry to juveniles should be less than 400 individuals/m2 to ensure the growth rate, survival rate, and to provide maximum utilization of the reservoirs.