The Characteristics of the Amur Sturgeon, Acipenser schrenckii, Spawners from a Warm-Water Cage Farm during Long-Term Exploitation

Resumo

The cultivation, biological, and production parameters of domesticated Amur sturgeon spawners of age 8 to 24 years from a warm-water cage farm are described. Female Amur sturgeons of three generations, bred from native spawners in cages, reach first maturity at ages of 8–10 years; males reach first maturity at ages of 6–7 years. Females have a larger body weight, length, girth, and fatness than those of males in all the age groups from 8 to 24 years. Males produce 40–350 mL of high-quality milt per one stripping session; first-maturing females produce 0.7–2.3 kg of roe. Most females (75%) spawn annually or biennially. Some females at ages of 17–23 years can produce a maximum of 7.0–10.5 kg of roe. The mean amount of roe collected from one female at ages of 8–24 is 3.82 kg, with a fecundity of 200 000 eggs (a maximum of 520 000 eggs), a relative working fecundity of 7500 eggs/kg (maximum 13 500 eggs/kg), and an oosomatic index of 14.5% (maximum 24.5%). During six to eight spawning seasons, an average of 22–31 kg of roe was obtained from the females of age 21 and 24 years, which accounts for 90–98% of their body weight. In 27% of the females, the amount of roe was 29–43 kg, or 103.0–137.5% of their body weight. The females adapt well to technological operations. Their survival rate for the period of exploitation is 65%.