长江下游中华绒螯蟹成蟹资源现状(2007~2011年)

根据2007~2011年在长江安徽段和江苏段的中华绒螯蟹成蟹汛期调查结果,研究了长江下游中华绒螯蟹的资源变动特征。中华绒螯蟹平均体重在空间分布上基本呈现由上游至下游逐步下降的趋势,在时间上各江段变动规律各有不同,最大平均体重出现于2010年的安庆江段,为0.25kg;最小平均体重出现于2008年的靖江江段,为0.05kg。安徽段总捕捞量为9.07~30.44t,汛末瞬时资源量为3.01~6.07t,总资源量为12.09~36.50t;江苏段总捕捞量为6.76~48.28t,汛末瞬时资源量为2.85~10.19t,总资源量为9.88~55.92t。近5a长江下游中华绒螯蟹汛期捕捞强度为0.75~0.86,捕捞压力处于高位,加之长江下游中华绒螯蟹幼蟹、蟹苗捕捞作业逐步恢复,中华绒螯蟹资源仍面临着严峻的问题。为促进中华绒螯蟹资源的可持续利用,建议全江禁捕,建立中华绒螯蟹保护区,加大增殖放流力度、加强科学研究及渔政管理。

STUDY ON CHINESE MITTEN CRAB RESOURCE IN THE LOWER REACHES OF YANGTSE RIVER(2007-2011)

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.