Abstract
This article presents the results of a 30-day study investigating the impact of varying oxygen concentrations and stocking densities on the growth and development of sterlet (Acipenser ruthenus) in a recirculating aquaculture system (RAS).As a result, it was established that a stocking density of 40 kg/m³ provides the best indicators of mass growth (relative increase of 55.6%, specific growth rate of 1.47%, absolute increase of 42.9 g, average daily increase of 1.43 g/day), which makes it optimal.High density (80 kg/m³) reduces growth by 17-21% compared to 40 kg/m³, which can be very important for production.Productivity is increased by density: maximum at 80 kg/m³ (114.4 kg/m³ and 91.5 kg/m²), then 60 kg/m³ (89.5 kg/m³ and 71.6 kg/m²) and minimum at 40 kg/m³ (61.8 kg/m³ and 49.4 kg/m²).The feed factor is minimal at 40 kg/m³ (1.23 units) and is increased to 1.29 units at 60 and 80 kg/m³, indicating a decrease in feed efficiency at higher densities.High stocking density (80 kg/m³) increases biomass gain and productivity (114.4 kg/m³, 91.5 kg/m²), but decreases individual gain and feed efficiency.Thus, the results of the studies showed that the optimal conditions for the normal growth and development of sterlet in recirculating aquaculture system (RAS) installations include the following parameters: a dissolved oxygen content of 8-10 mg/L and a stocking density of 40-60 kg/m³.