THE AFFECT OF DENSITY ON BESTER (H. HUSO x A. RUTHENUS) LARVAE REARED IN A SUPERINTENSIVE SYSTEM
D. Oprea, L. Oprea
The experiment was come off in a flow-through super intensive system, sturgeon larvae being reared in spun glass troughs. Experiment duration was 20 days. Biological material, bester larvae was gained by artificial breeding of breeders, beluga female (H. huso Brandt, 1869) and sterlet males (A. ruthenus, Linné, 1758) respectively, catch from natural environment. The experiment was going off with three variants and three replications each, rearing densities were as follow: in variant I - 300 ex/tank, in variant II - 400 ex/tank, and in variant III - 500 ex/tank. In all three experimental variants, the feeding of larvae was achieved in the same way, namely the same number of daily intakes, delivery in the same time for all variants and it was used the same type of meal, namely Daphnia species, Tubifex species and fodder. At the end of experiment, the results were: in variant I, the survival rate was 70 %, and final average body mass of larvae 3 g/ex, in variant II, survival rate was 66 %, and final average body mass 2.3 g/ex, and in variant III, survival rate was 48 %, and final average body mass 1.4 g/ex.