Shan Xiu-Juan, Zhuang Zhi-Meng, Jin Xian-Shi, Dai Fang-Qun
Shandong Province Key Laboratory for Fishery Resources and Eco-environment, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China.
Ying Yong Sheng Tai Xue Bao. 2011 Dec;22(12):3321-8.
Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg x h(-1) and 1800 kg x h(-1) in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5 degrees E, 28.5 degrees N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus, and Acropoma japonicum) and pelagic species (Psenopsis anomala, Octopus variabilis) and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.
基于2007年5月以及2008年5月和6月的底拖网调查数据，本文分析了大型水母丰度动态对长江河口及其邻近水域渔业资源的种类组成、分布和丰度的影响。从2007年5月至2008年6月，大型水母的单次拖网平均渔获量和最高渔获量均有所增加，2008年6月分别达到222.2千克×小时⁻¹和1800千克×小时⁻¹。大型水母主要分布在50米等深线附近区域，未超出东海沿岸水、长江径流和台湾暖流的交汇锋面所在的100米等深线。与5月相比，6月大型水母的主要分布区域向北迁移，2007年5月和2008年5月大型水母的最高渔获量出现在同一采样站（东经122.5度，北纬28.5度）。在大型水母丰度较高的采样站，渔业资源丰度较低，渔业种类也发生了很大变化，主要由小型种类（日本竹荚鱼、龙头鱼和日本发光鲷）、中上层种类（中华眶棘鲈、长蛸）以及日本带鱼和中华眶棘鲈组成，中华眶棘鲈在2008年6月的总渔获量中占23.7%。在大型水母丰度较高的采样站，小黄鱼在总渔获量中也占较高比例，但未发现底层种类黄鮟，仅采集到少数甲壳类动物。本研究表明，大型水母对长江河口渔业生态系统中的渔业群落结构和丰度具有显著负面影响，并进而通过级联营养相互作用改变了生态系统的能量流动模式。因此，在考虑相应的渔业管理措施时，强烈建议将大型水母视为一个独立的生态群体。
