秋季长江口鱼类浮游生物群落时空结构

Temporal and Spatial Structure of Ichthyoplankton Assembleges in the Yangtze Estuary During Autumn

根据1998—2009年11月长江口及其邻近海域7个航次的调查资料,探讨了秋季长江口鱼类浮游生物群落种类组成、群落结构及多样性时空变化特征。研究结果显示,7个秋季航次共捕获鱼类浮游生物969个(尾),隶属于10目19科33种,以鲈形目种类最多(7科9种)。秋季长江口鱼类浮游生物以沿岸型种类最多(12种),其次是半咸水(10种)和近海种类(9种),淡水种类最少(4种)。秋季长江口鱼类浮游生物优势种年度间演替显著,对鱼类浮游生物群落丰度贡献最大的种类包括:半咸水型的矛尾鰕虎鱼(Chaeturichthys stigmatias)和前颌间银鱼(Salanx prognathus)、沿岸型的康氏小公鱼(Stolephorus commersonnii)、近海型的鳀(Engraulis japonicus)和带鱼(Trichiurus lepturus)。2004年以后,长江口鱼类浮游生物种类数量、丰度和多样性均显著高于2004之前的调查航次。ANOSIM分析显示,长江口鱼类浮游生物群落结构年度间差异显著,且2007和2009年与其他年度不相似性最高。可以看出,秋季长江口鱼类浮游生物种类组成呈年度变异状态,2004年后长江口鱼类浮游生物群落结构变异最大,多样性呈增加趋势。

In this study, the spatial and temporal patterns in the species composition, distribution and abundance of ichthyoplankton were identified in the Yangtze Estuary and its adjacent sea waters. Seven surveys were conducted during November in 1998, 2000, 2002, 2003, 2004, 2007 and 2009, respectively, and ichthyoplankton was sampledfrom 40 stations. A total of 969 ichthyoplankton, representing 19 families and 33 species, were collected. Ichthyoplankton species was dominated by order Perciformes （7 families and 9 species）. Ichthyoplankton assemblages had three habitats, brackish （12 species）, coastal （10 species） and offshore （4 species） groups. The dominant species had a significant annual succession. Brackish species, Salanz prognathus and Chaeturichthys stigmatias, coastal species, Stolephorus commersonnii, and offshore species, Engraulis japonicus and Trichiurus lepturus, had the greatest contribution to the total ichthyoplankton abundance. Species richness, abundance and diversity of ichthyoplankton showed a distinctly increase since 2004. ANOSIM analysis indicated that the annual variations of ichthyo- plankton stucture were significant in the Yangtze Estuary, and the dissimilarities of ichthyoplankton as- semblages were the highest between 2007, 2009 and other surveys. Ichthyoplankton species composition presented distinct annual variation in the Yangtze Estuary during autumn. Since 2004 in wich ichthyo- plankton structures had dedicated the greatest variance, ichthyoplankton diversity had shown increasing trend.