太湖日本沼虾繁殖生物学研究

Reproductive biology of Macrobrachium nipponense in Lake Taihu

对2004年11月至2005年11月太湖梅梁湾和贡湖湾的日本沼虾繁殖生物学进行了研究.梅梁湾采样期间日本沼虾的月性比变化于0.61～1.77之间,总平均性比为1.03,贡湖湾采样期间的月性比变化于0.55～1.65之间,总平均性比为0.99,卡方检验雌雄数量差异均不显著(P>0.05).梅梁湾与贡湖湾日本沼虾主要繁殖期为4月下旬至9月下旬.抱卵率出现6月和8月两个高峰,前者高于后者.5～7月繁殖群体以越年虾为主,8月份以小规格的当年虾占绝大部分.绝对抱卵量与体质量呈直线相关,与体长成指数关系.相对抱卵量与体质量、体长没有相关关系.8月份越年虾绝对繁殖力显著大于当年虾,但相对繁殖力没有明显差异.梅梁湾5月、8月绝对繁殖力和相对繁殖了显著高于贡湖湾,抱卵虾体长、体质量也较贡湖湾大.5月份、8月份梅梁湾日本沼虾性腺成熟系数分别为(21.0±8.7)%(n=5)、(15.7±6.2)%(n=63),两者没有显著性差异(P>0.05).

Reproductive biology of Macrobrachium nipponense was studied during Nov 2004 through Nov 2005 in Taihu Lake.During sampling,monthly sex ratio of Macrobrachium nipponense was in the range of 0.61~1.77 with an average of 1.03 in Meiliang Bay;while in the range of 0.55~1.65 with an average of 0.99 in Gonghu Bay.The main breeding season began in the late April and lasted until late September.Spawning peaks occurred in June and August.Number of hatched eggs was linearly related to the body mass and exponentially related to the body length.In August,the annual shrimps had higher absolute fecundity than those of shrimp of age 0,but the relative fecundity was not significantly different from each other.The gonad somatic index(GSI) of Macrobrachium nipponense in May and August were(21.0±8.7)%(n=5)、(15.7±6.2)%(n=63) respectively in Meiliang Bay.