莱州湾春季鱼卵仔稚鱼群落结构和物种多样性

于2007—2010年春季(5月)利用大型浮游生物网对莱州湾海域位置相同的12个站位进行4个航次拖网调查,研究分析了该海域鱼卵仔稚鱼群落组成、优势种、空间分布及其多样性特征。结果表明:4个航次共获得鱼卵、仔稚鱼26种,隶属于6目16科24属,1种衔科鱼卵鉴定到科,另有1种鱼卵未能鉴定种类。鱼卵、仔稚鱼分布不均匀,莱州湾西部还湾底海域分布较多。斑鰶(Konosiruspunctatus)为该海域鱼卵的第一优势种;鳀(Engraulisjaponicus)在2007年和2008年作为仔稚鱼的第一优势种出现,而2009年和2010年仔稚鱼的第一优势种则是虾虎鱼。调查期间该海域鱼卵、仔稚鱼的均匀度指数和生物多样性指数变化趋势一致,均表现为从2007年开始随年代递减的趋势;种类数和丰富度指数则从2008年开始呈现随年代递减的趋势。2007—2010年4a鱼卵仔稚鱼聚类结果显示,2007年和2008年鱼卵仔稚鱼群落结构相似,与2009年和2010年均有差异。与1982年山东省近岸调查结果相比,莱州湾海域鱼卵仔稚鱼群落结构发生明显变化,斑鰶取代鳀成为第一优势种,小黄鱼等经济鱼类数量逐渐降低。

Structure and Species Diversity of Ichthyoplankton in Spring in Laizhou Bay

The community structure, dominant species,spatial distribution, and diversity of ichthyoplankton in Laizhou Bay were studied based on trawl survey data in spring (May) from 2007 to 2010. Twelve fixed sampling stations were established in the investigation area. During the investigation, 26 ichthyoplankton taxa were collected, of which 24 taxa were identified and belonged to 24 genera, 16 families, and 6 orders. One taxon of Callionymidae fish was identified to the family level only, and the taxon of an egg sample was unidentified. The distribution of ichthyoplankton in Laizhou Bay was uneven; eggs were richer in the west and southeast, but larvae were richer in the west. The dominant eggs in all years were Konosiruspunctatus; 83% (n=5543) of all specimens in 2008 were K. punctatus. The dominant larvae in 2007 and 2008 were Engraulis japonicas, and Gobiidae fishes were dominant in 2009 and 2010. The dominant species of larvae changed from pelagic-neritic continental shelf fish to demersal continental shelf species. The diversity (H) and evenness (J) indices showed a decreasing trend from 2007, and the species diversity (S) and species richness (D) indices showed a decreasing trend from 2008. Cluster analysis showed significant differences among years in the community structure of eggs, larvae, and juveniles; the community structure of eggs and larvae was similar in 2007 and 2008. Compared to results from a 1982 survey offshoreof Shandong Province, the community structure of ichthyoplankton in Laizhou Bay has changed. K. punctatuswas the dominant species, and the numbers of economic fish species such as Larimichthyspolyactis have decreased.