GROWTH DYNAMICS OF CHINESE MITTEN CRAB, ERIOCHEIR SINENSIS, STOCKED IN LAKES ALONG THE MIDDLE REACHES OF YANGTSE RIVER

The propagation of Chinese mitten crab, Eriocheir sinensis, in shallow lakes with dense submerged macrophyte has been verified to be one of the high efficient ecological fishery models in China. Therefore, to master the laws of the crab growth is very important for the lake fishery management.The post-larvae and juvenile crabs were stocked in Lake Biandantang, Lake Longwangtou and the embayment of Lake Niushan. From March 21 to October 20,1997, 14 fish-hedges were installed in the lakes for monthly sampling. Carapace width and length (cm), and body weight (g) were measured monthly except July when fishing was forbidden. The causes of growth difference in the three lakes were discussed. The instantaneous growth rate of crab body weight in these Lakes were calculated.The growth dynamics of the crab body weight during Mar-Oct., 1997 fitted fairly well with logistic equation and may be expressed as follows:Lake Longwangtou female:BW = 150(1 + exp(3.328-0.445T)-1 male: BW = 180(1 + exp(4.739-0.742T))-1 female + male: BW =165(1 + exp(4.27 - 0.646T))-1 Lake Biandantang female: BW = 150(1 + exp(4.635 - 0.69T))-1 male: BW = 180(1 + exp(3.342 - 0.563T))-1 female + male:BW = 165(1 + exp(3.637 - 0.583T)-1 Lake Niushanhu female:BW = 150(1 + exp(7.617 - 0.931T))-1 male; BW = 180(1 + exp(8.19 - 1.012T))-1 female + male:BW = 165(1 + exp(7.911 - 0.972T)) -1where, BW is body weight (g) and T is time (month)