OBSERVATION ON THE REPRODUCTIVE GLANDS OF ADULT ACIPENSER SINENSIS GRAY IN CHANGJIANG RIVER BELOW GEZHOUBA DAM

Acipenser sinensis Gray is a large, migratory fish. They are used to feed and grow in the areas around sea-shore and estuary of the River Changjiang. In each autumn, mature individuals ascend to the upper river for spawning. Since the building of the Gezhouba Hydroelectric Project in 1981, their migratory trail has been interrupted by the dam. In order to find out whether the sturgeons are capable of normal maturity in downstream section, the present study was undertaken.Both external feature and microscopical structure of overies and testes of the sturgeons collected from the Changjiang River at the section near Yichang were observed. Details are given in the paper. It is worthy of mention that there were several mature sturgeons with overies of stage ⅲ, Ⅳ, Ⅵ and testes of stage Ⅲ, Ⅳ, Ⅴ found in the specimens collected in the autumn of 1981. Furthermore, in the autumn of 1982, eggs and fry of the sturgeons were collected at the section below the dam. It indicates that sturgeons living in downstream section of the dam are not only able to be fully mature but also capable of natural spawning.Acipenser sinensis is endangered so far in China. For further protection and propagation of this species, the authors are inclined to believe that artificial propagation and releasing are practicable and effective. Measures should also be taken to prevent this fish from overfishing.