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根据2007年5月、2008年5月和6月对长江口及其邻近水域渔业底拖网调查资料,分析了该水域大型水母资源量变化对渔业种类组成、分布和资源量的影响.结果表明:2007年5月—2008年6月,大型水母的平均网获量和最高网获量增加,2008年6月平均网获量为222.2kg.h-1,最高网获量达到1800kg.h-1.大型水母主要分布在50m等深线附近,及100m等深线以浅的东海沿岸流、长江径流和台湾暖流的锋面上,6月大型水母的集中分布范围与5月相比向北偏移,在2007年5月和2008年5月两次调查中均存在一个水母集中分布点(122.5°E,28.5°N).大型水母和渔业资源呈交错分布,大型水母集中分布的区域,渔业资源网获量降低,种类组成也发生了显著变化.在水母网获量高的站位主要以小型种类(竹筴鱼、龙头鱼、发光鲷等)或中上层种类(刺鲳、长蛸)及带鱼为主,刺鲳在2008年6月的调查中占整个渔获量的23.7%,小黄鱼也占有较高的比重,但一些底层种类如黄鮟鱇等在水母集中分布区没有发现,虾蟹类也相对较少.大型水母对长江口渔业生态系统的群落结构和资源量都产生了一定的影响,而且水母可以通过营养级联反应改变系统的能流方式.因此,在保护渔业资源和制定相关的渔业管理措施时,建议将水母作为一个独立的生态类群来考虑.
Based on the investigation data of bottom trawl fisheries in the Changjiang Estuary and its adjacent waters in May 2007, May and June 2008, the effects of the changes of the large-scale jellyfish resource on the species composition, distribution and resources of the fisheries were analyzed.The results showed that: From May 2007 to June 2008, the average net harvest and the maximum net harvest of jellyfish increased. The average net harvest in June 2008 was 222.2kg.h-1, and the maximum net harvest reached 1800kg.h-1 . The major jellyfish are mainly located near the 50 m isobath and the shallow east coast, the Yangtze runoff and the warm front of Taiwan at the 100 m isobath. The distribution range of the large jellyfish in June is shifted northward from May, There was a jellyfish concentration point (122.5 ° E, 28.5 ° N) in both surveys in May 2007 and May 2008. Large jellyfish and fishery resources were staggered and concentrated in areas with large jellyfish, and the Fisheries Resources Network And the species composition also changed significantly.In the stations with high quantity of jellyfish, the main types are small species (mackerel, faucet, seabream, etc.) or pelagic species Mainly, Crabfish accounted for 23.7% of the total catches in the June 2008 survey, small yellow croaker But also accounted for a higher proportion, but some of the underlying species, such as yellow grubs, were not found in the jellyfish concentration distribution area, shrimp and crabs are relatively small.Jellyfish jellyfish community on the Yangtze River estuary fishery ecosystem structure and resources have a certain amount of Influence, and jellyfish can change the system’s energy flow through nutrition cascade reaction.Therefore, when protecting fishery resources and formulating related fishery management measures, it is suggested to consider jellyfish as an independent ecological group.