2004和2007年春季长江口近海鱼类群落特征及其与环境因子的关系

Fish Assemblage Structure in Adjacent Sea of Changjiang Estuary in Spring of 2004 and 2007 and Its Association With Environmental Factors

根据2004年5月和2007年5月长江口近海渔业资源调查数据,应用双向指示种分析(TWINSPAN)和典范对应分析(CCA)方法,分析了春季长江口鱼类群落特征,探讨了春季长江口鱼类群聚结构及其与环境因子的关系。结果表明,2个春季航次共捕获鱼类生物9目25科36种,其中带鱼(Trichiurus lepturus)、黄鲫(Setipinna taty)、鳀(Engraulis japonicas)、竹荚鱼(Trachurus japonicas)、小黄鱼(Larimichthys polyactis)和鲐(Scomber japonicas)为优势种。2004和2007年长江口近海鱼类存在4个生物群聚:以鲐为特征种的南部高温型、以带鱼为优势种的南部低温型、以竹荚鱼为代表的北部高温型和以黄鲫占绝对优势的北部低温型。影响2004和2007年长江口海域鱼类分布的主要环境因子为水深、底层总磷、表层悬浮体含量、底层盐度和表层温度。其中,水深、盐度和悬浮体含量驱动鱼类群聚空间变异,温度驱动了时间变异。与1999—2001年相比较,2004和2007年长江口鱼类群落发生显著变异,鱼类资源种类数量和生物量减少,优势种亦发生演替;水深、盐度、温度变异对鱼类群聚分布保持影响力,水域悬浮体含量成为鱼类群聚空间变异的重要驱动因素。

Characteristics of fish assemblage structure were described according to data collected in the spring cruises of 2004 and 2007 in the adjacent sea of Changjiang Estuary, with the relationship between such a structure and the environmental factors determined with two-way indicator species （TWINSPAN） and canonical correspondence analysis （CCA）. The fish captured in 2 cruises were assigned to 36 species belonging to 25 families, 9 orders, of which Trichiurus lepturus, Setipinna taty, Engraulis japonicas, Trachurus japonicas, Larimichthys polyactis and Scomber japonicas dominantly inhabited the area. These fish species could be classified into south high-temp assemblage that was represented by Scomberja- ponicas ~ south low-temp assemblage that was dominated by Trichiurus lepturus ; north high-temp assem- blage that was featured by Trachurus japonicas and north low-ternp assemblage that was predominated by Setipinna taty. Water depth, bottom total phosphorus, surface total suspended material （TSM）, bottom salinity and surface temperature were major factors influencing the formation of fish assemblages in the ar- ea. Of these factors, depth, salinity and TSM drove the spatial variation of fish assemblage structure, and temperature impacted their temporal variation. Comparing to the described according to data collected during 1999--2001, fish community varied significantly in 2004 and 2007; species and biomass decreased, the dominant species changed, and fish community succession was undergoing.