Abstract:

The resource characteristics of the Chinese mitten crab Eriocheir sinensis were studied in the fishing season from 2007 to 2011 in the Anhui and Jiangsu section of the lower Yangtze River. The average weight of the Chinese mitten crab gradually decreased from upper stream to the downstream, and the average weight fluctuation patterns in different river section were different. The maximum value of the average individual weight was represented as 025 kg/ind., observed in the Anqing section in 2010. While the minimum value of 005 kg/ind. was observed in the Jingjiang section in 2008. In the Anhui section, the annual total catch amount was 907-3044 t, with an instantaneous catch amount of 301-607 at the end of fishing season. In the Jiangsu section, the annual total catch amount was 676-4828 t, with an instantaneous catch amount of 285-1019 t at the end of fishing season. Further, the total resources ranged between 1209-3650 t and 988-5592 t in Anhui and Jiangsu section, respectively. These results showed that the Chinese mitten crab resources appear rebounding significantly from 2007 to 2011 in lower reaches of the Yangtze River, compared with the results from 1996 to 2005, which is probably caused by the proliferation of releasing and fishing moratorium and other resource protection measures.However, the Chinese mitten crab resources in the lower Yangtze River are still facing several rigorous difficulties as following. The 5year catch strength index ranged between 075 and 0.86, indicating that the crabs were still under the high catch pressure from 2007 to 2011. Meanwhile the capture of crab larvae and juvenile crab had been rising again, and the Chinese mitten crab also faced the interferences from other artificial activities. In order to maintain the sustainable development of the Chinese mitten crab, it is recommended to carry out the following measures such as banning on catching crabs in the Yangtze River, strengthening the establishment of crabs conservation area, increasing enhancement and releasing quantity, strengthening scientific research and the fisheries management.