STUDIES ON DYNAMIC CHANGE OF MATURED MITTEN CRAB RESOURCE IN THE MIDDLE AND LOWER REACHES OF THE YANGTZE RIVER

According to the data from continuous monitoring during 1989～1999,the average body length, body width and body weight of matured mitten crab caught from the Yangtze River were 58mm, 63mm and 131g respectively. The ratio of female to male was 1:0.92 in the catching. The peak season of the crab catching was from Oct. 4 to Oct. 19 in the middle and lower reaches of the river and late November in the estuaries. As the result of drastic declining of the matured mitten crab resource, the catching season of matured mitten crab disappeared in the river course upper than NanJing. The authors analyzed the reproductive migration and the present catching of the crab in the Yangtze River. Protective measures on the crab resource in the Yangtze River were also suggested in the paper.