武湖日本沼虾繁殖生物学研究

武湖日本沼虾产卵场位于全湖沿岸带．越冬虾主要繁殖期为春夏季(4月中旬～7月中旬，水温20．5～31℃)。当年虾繁殖期为秋季(7月中旬～9月中旬，水温31～23℃)，7月中下旬为新老世代交替期．非繁殖季节雄虾多于雌虾，繁殖季节雌虾多于雄虾．越冬虾绝对繁殖力明显大于当年虾．绝对繁殖力与体长呈幂函数关系，与体重呈直线相关．相对繁殖力RW为常数，其95％置信区间为1067．76±16．94eggs·g^-1。

Reproductive biology of Macrobrachium nipponensis in Lake Wuhu

Macrobrachium nipponensis is a key species of freshwater shrimps in China. To know its reproductive biology is very important for its protection and rational use. Studies from September 1998 to September 1999 in LakeWuhu showed that the spawning ground of M. nipponensis was situated in the littoral zone of the whole lake. The main spawning period of overwintering shrimps was from mid-April to mid-July (water temperature 20.5-31 degrees C), and that of non-overwintering shrimps was from mid-July to mid-September (water temperature 31-23 degrees C). The sex ratio (female:male) increased gradually during the spawning period, and the absolute fecundity of overwintering shrimps was higher than that of non-overwintering ones. The relationship between absolute fecundity and body length and between absolute fecundity and body weight could be expressed as cubic equation and simple linear equation, respectively. The relative fecundity (RW) of M. nipponnensis could regard as a constant, and its 95% confidence limits was 1067.76 +/- 16.94 eggs.g-1.