Preliminary analysis on precocious phenomenon of mitten crab, \%Eriocheir sinensis \% reared in ponds

Effects of different accumulative temperature, nutrition and strain on preconciousness of mitten crab \%Eriocheir sinensis\% were studied by using the orthogonal design method. Extra morphological characters and internal sexual gland development of mitten crab indicate the proportion of precocious mitten crab. It was found that precocious proportion was different among different strains of mitten crab, that is, hereditary factor is the chief cause of preconciousness. A way to discriminate preconciousness of male crabs was developed by inner side seta of second ambulatary leg, when the animals reach about 2.0 mm length. When mitten crab mature, gonadosomatic index will be over 0.8%.