[Reproductive biology and artificial propagation of Acipenser sinensis below Gezhouba Dam]

A total of 36 females and 21 males of Chinese sturgeon Acipenser sinensis were caught in 1998-2004 excluding 2002 to study the characteristics of their reproductive biology and the effect of their artificial propagation. The results showed that the body length (BL), body mass (BM) and age of the females were 240-320 cm, 140-432 kg, and 15-30 years, and those of the males were 153-284 cm, 70-244 kg and 12-26 years, respectively. The inducing rate was 93.1% for females and 100% for males, and the ova had 7 different colors. The absolute fecundity was 200,000-590,000 eggs, with an average of 358,000 eggs, and the relative fecundity to BM was 820-3,020 eggs per kg, with an average of 1,590 eggs per kg. The sperm had 4 different colors. The absolute sperm quantity obtained from one male was 1,000-5,952 ml, with an average of 2,597.8 ml, and the relative sperm quantity to BM was 1.25-31.24 ml . kg(-1), with an average of 13.3 ml . kg(-1). During the study period, the average fertilization rate in artificial propagation was 63.7%, and the hatching rate was 48.1%, with 4,762,000 fry obtained. Compared with the data in 1976, the natural reproductive capacity of the Chinese sturgeon broodstocks declined greatly.