长江口及其邻近海域仔鱼的生态学研究

The ecological study of fish larvae in the Yangtze River Estuary and adjacent waters

根据2006—2007年长江口春、夏、秋、冬4个航次共504个站位的调查资料,对该海域仔鱼种类组成、数量分布、季节变化以及与环境因子的关系进行了分析。结果表明:四个季节采集到的仔稚幼鱼样品共82种,隶属16目48科,其中鲈形目种类最多,有21科34种,其次是鲱形目和鲉形目,分别有3科10种和5科8种。仔鱼种类数及丰度有明显的季节和空间变化,仔鱼种类数呈现:夏季(39种)>春季(38种)>秋季(25种)>冬季(16种);仔鱼丰度大小按季节依次为夏季(185尾/100m3)>春季(37尾/100m3)>秋季(6尾/100m3)>冬季(1尾/100m3)。仔鱼优势种有明显的季节变化,春、夏、秋三季优势种分别为鳀鱼、凤鲚、长鳍底灯鱼,冬季优势种不明显。多元统计方法分析结果显示:春季仔鱼群落中的绝大部分物种均受到水深和表层盐度两个环境因子的控制;夏季大部分物种则更偏好于高叶绿素和表层水温相对较低的河口近岸水域。

The categories composition and abundance distribution of fish larvae in the Yangtze River Estuary and vicinity waters were analyzed based on data from four seasonal surveys at 504 sampling stations during2006 to 2007. Eighty-two species of fish larvae were collected,belonging to 16 orders,48 families. Among them,Perciformes was the most diverse group,with 34 species from 21 families. Scorpaeniformes,including3 families,10 species,and Clupeiformes,including 5 families,8 species,were the next diverse fauna. There was clearly seasonal and spatial variation of theabundance of fish larvae and the number of species of fish larvae. The seasonal abundance of fish larvae was listed as summer（ 185 ind/100m^3） 〉spring（ 37 ind/100m^3）〉 autumn（ 6 ind/100m^3）〉 winter（ 1 ind/100m^3）,and they mainly centered in spring and summer. The average abundance of fish larvae was higher in summer than in spring and the distribution areas were more to the west in summer. The number of the fish larvae species was in the order of summer（ 39species） 〉spring（ 38 species） 〉autumn（ 25 species） 〉winter（ 16 species）. The dominant species were Engraulis japonicas,Coiliamystus,Benthosemapterotum in spring,summer and autumn respectively.Multivariate statistical analysis showed that in spring,the distribution of most species of ichthyoplankton was controlled by depth of water and surface salinity. While in summer,most species preferred the estuarine and coastal waters,which was characterized by higher chlorophyll a concentration and surface temperature.