长江中游湖泊放流河蟹的生长动态

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

在保安湖的两个湖区（扁担塘和龙王头）和牛山湖的一个围拦湖汊中对放流河蟹的生长指标逐月采样研究，结果表明，三个水体虽同属长江中下游典型草型湖泊，但河蟹在生长末期规格（壳宽、体重）上表现出一定差异。扁担塘（瓯江种）、龙王头（瓯江种＋长江种）成蟹规格较一致，群体壳宽分别为6.70±0．59、6．73±0．56cm，体重分别为155．1±36．0g、158．0±36.1g。而牛山湖湖议成蟹壳宽为5．63±0．43cm，体重为103．2±26.3g，与前两者相比，差异显著。原因可能主要是后者放养时间太晚（1997年4月26日）。从瞬时生长率来看，牛山湖湖（天津种）为0．02687g·day-1，大于扁担塘（0．00977g·day-1）和龙王头（0.00997g·day-1）。作者给出了上述三个水体2龄河蟹体重生长的逻辑斯蒂曲线方程。

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)-1male: BW = 180(1 + exp(4.739-0.742T))-1female + male: BW =165(1 + exp(4.27 - 0.646T))-1Lake Biandantang female: BW = 150(1 + exp(4.635 - 0.69T))-1male: BW = 180(1 + exp(3.342 - 0.563T))-1female + male:BW = 165(1 + exp(3.637 - 0.583T)-1Lake Niushanhu female:BW = 150(1 + exp(7.617 - 0.931T))-1male; BW = 180(1 + exp(8.19 - 1.012T))-1female + male:BW = 165(1 + exp(7.911 - 0.972T)) -1where, BW is body weight (g) and T is time (month)