| The Chinese mitten crab is one of the most important crabs for aquaculture in China.According to their living water,they can be divided into several different geographical regions: the Yangtze River,the Liaohe River and the Ou River.The Chinese mitten crab raised by the Yangtze River farming methods are fat which is the quality germplasm.In the late 1980 s.Since the propagation technique for Chinese mitten crab matured,and due to the achieving higher production and a larger scale,some srains were mixed,and the germplasm resources of Chinese mitten crab degenerated continually,which have effected the healthy development of the industry.We choose some ponds which have similar conditions and start the research,breeding three different strains of the crab(artificial breeding of the Yangtze River estuary,wild Yangtze River estuary and Yangtze River estuary wild first generation).The survival rate of breeding stage,FCR,farming properties were tested and analyzed.The results showed that(1)which were the same sizesunder Larvae specifications identical conditions,the wild population G0 and growth rate G1 males grew significantly faster than the control group,the average size of the final develop after significantly larger than the control group,the difference in growth rate was seen in the after August;final average size.(2)Wild G0 female body is also greater than in the control group,the growth rate difference between females appear in July;(3)the survival rate of wild G0 was significantly higher in the control group than in the wild FCR G0 higher than 20%,higher than the total group of wild G0 other two groups,the control group higher than about 24%.These results,wild crab output under natural conditions,the Yangtze River estuary and its outstanding performance in the first generation breeding performance,and can cultivate by genetic selection,purification and rejuvenation of germplasm for further optimization. |
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