苏北浅滩中部典型沙脊潮沟海域不同空间鱼类群落的分析

利用2011年5月(春季)和2010年11月(秋季)在苏北浅滩大丰沿岸海域(32°44?~33°23?N、120°54?~121°38?E)开展渔业资源调查获取的资料,运用聚类分析方法划分群落结构,从鱼类的种类组成、多样性以及优势种等不同方面,探讨苏北浅滩沙脊潮沟地形对鱼类群落的影响。研究表明:春秋季苏北浅滩沙脊潮沟沿岸海域鱼类可划分为西部近岸群落、中部沙脊群落以及东部潮沟群落3个群落,其鱼类群落结构差异表现为,春季鱼类总种类数表现为潮沟(15种)沙脊(11种)近岸(3种);多样性指数(H')类似,即潮沟(1.57,1.89)沙脊(1.19,1.57)近岸(0.51,0.69);秋季鱼类种类数表现为潮沟(18种)近岸(12种)沙脊(11种),鱼类多样性指数表现为潮沟(1.54,1.54)近岸(1.02,0.96)沙脊(0.92,0.83)。潮沟海域与外海相连,外海鱼群顺着潮沟向近海移动,在潮沟末端遇到沙脊地形的阻挡,底栖性鱼群停留在沟底,造成种类数累积,多样性增加。优势种分布上,潮沟群落多为方氏锦鳚(Pholos fangi)、鮸(Miichthys miiuy)、小带鱼(Eupleurogrammus muticus)等产卵性鱼类;沙脊群落鱼类主要由赤鼻棱鳀(Thryssa kammalensis)和大银鱼(Protosalanx chinensis)等滤食性鱼类组成。苏北浅滩沙脊潮沟海域鱼类群落空间差异显著,而地形变化以及由此导致的环境变化是苏北浅滩沙脊潮沟海域鱼类群落结构差异的主要原因。以沙脊潮沟地形因素为突破口,不仅丰富了鱼类群落结构变化的环境影响因素,也为苏北浅滩渔业的管理和保护提供可靠依据。

Analysis of different spatial fish communities in a sand ridge and tidal creek system in the central North Jiangsu shoal, China

We analyzed data from the investigation of fishery resources in Dafeng, off the north coastal waters of Jiangsu Province, east of China, to examine the community structure and influences upon it. Cluster analysis was used to divide the community structure based on the spatial distribution of species composition, diversity and do-minant species. We found that during the spring (May) and autumn (November) the coastal water fishes in the northern Jiangsu shoal could be classified into three communities: the coastal waters to the west of the sand ridge; the sea of the central sand ridge; and the tidal creek. The difference in fish community structure was also demon-strated by the total number of fish species in spring [tidal creek (15)>sand ridge (11)>coastal (3)]; and autumn [(tidal creek (18)>coastal (12)>sand ridge (11)]. There was a similar diversity index in spring [tidal creek (1.57,1.89), sand ridge (1.19,1.57)>coastal (0.51,0.69)]; and autumn [tidal creek (1.54,1.54)>coastal (1.02,0.96)> sand ridge (0.92,0.83)]. The tidal creek and open sea are adjacent, so the sand ridge obstructs the sea fish in mov-ing offshore when encountering the end of the tidal creek and makes the benthic fishes stay at the bottom of the ditch which render the accumulation of species, diversity increasing. The spatial distribution of dominant species shows that tidal creek species are mostlyPholos fangi,Miichthys miiuy,Eupleurogrammus muticus and other spawning fishes; the sand ridge mostly consists ofThryssa kammalensis,Protosalanx chinensisand other fil-ter-feeding fishes. We conclude that the community structure of fishes in the sandy ridge and tidal creek in the northern Jiangsu shoal varies, and that topographic changes and environmental change caused by the terrain are the main reasons for this. Using the topography of the tidal creek and sand ridge is an advance that not only fo-cuses on the environmental factors influencing fish community structure changes, but also provides a reliable basis for the management and conservation of fisheries in Subei shoal.