Growth and maturation in sterlet <Emphasis Type="Italic">Acipenser ruthenus</Emphasis> under high concentrations of dissolved oxygen

This study investigates the effect of high dissolved oxygen concentrations (DO) on sterlet Acipenser ruthenus maturation. Two groups, each comprising 246 individuals of 8-month-old juvenile sterlets, were reared for 37 months under high DO (group H, mean DO of 11.2 mg/L) or normal DO (group C, mean DO of 7.3 mg/L). Significant differences in body weight were observed between group H (638.7?±?191.9 g) and group C (572.2?±?151.9 g) in 12 months (P?<?0.05). Growth until 12 months occurred at a specific growth rate of 0.6%/day for group H and at 0.5%/day for group C. The food conversion rate of groups H and C was 5.2 and 5.8, respectively. The gonadosomatic index of group H was 3.1?±?1.1 for females and 3.1?±?9.7 for males, and showed no significant difference with group C (3.0?±?0.7 for females and 2.8?±?8.9 for males, P?>?0.05) in 24 months. Significant differences in follicle diameter in mature females were also observed. Group H included 68 mature females, with an average follicle diameter of 2318.0?±?175.3 µm, whereas group C included 56 mature females, with a smaller average follicle diameter of 2152.3?±?287.0 µm (P?<?0.001). However, the polarization index in group H (0.194?±?0.049) was higher than that in group C (0.178?±?0.042) (P?<?0.05). These results suggest that, for sterlet, rearing conditions with high DO can affect growth of both the body and follicle diameter of fish compared to normal rearing conditions.