东海中南部外海虾类组成特征分析

依据2006年5月（春）、8月（夏）、11月（秋）和2007年2月（冬）在东海中南部外海（26°00′-28°30′N,126°00′E以西）海域虾类资源调查资料,对该海域虾类的种类组成季节变化和空间格局特征作了分析。结果表明：东海中南部外海虾类季节间相似性指数较低,各季节贡献率较大的有长角赤虾、戴氏赤虾、东海红虾和假长缝拟对虾等种类。东海中南部外海虾类种类组成可分为A、B两个组群,A组群主要分布在126°00′E以西100 m等深线附近海域,主要以戴氏赤虾、长角赤虾、假长缝拟对虾、高脊管鞭虾和东海红虾为主;B组群主要分布在126°00′E以东100 m等深线附近海域,主要以脊单肢虾、日本异指虾和九齿扇虾为主。两个群聚类型的空间分布没有明显的群聚边界,但密集区有所不同。

Spatial Distribution of Shrimp Assemblages in the Offshore Waters of the Mid-Southern East China Sea

The seasonal variation of shrimp species composition and their spatial patterns are analyzed based on the data obtained in seasonal surveys of the Mid-Southern East China Sea（26°00′-28°30′N,121°00′-126°00′E） in May,August and November,2006 and in February,2007.The results indicated that the similar-ity index of shrimp species composition among different seasons was low,and the dominant species were Metapenaeopsis longirostris,Metapenaepsis dalei,Plesionika izumiae,Parapenaeus fissuroides,and etc.A and B shrimp assemblage styles were identified in the Mid-Southern East China Sea by hierarchical cluster analy-sis and non-Metric Multidimensional scaling（MDS）.The dominant species of A shrimp assemblage were main-ly concentrated in the area around 100 m isobath to the west of 126°00′ E,such as Metapenaepsis dalei,Metapenaeopsis longirostris,Parapenaeus fissuroides,Solenocera alticarinata,Plesionika izumiae,and etc.The dominant species of B shrimp assemblage were mainly concentrated in the area around 100 m isobath to the east of 126° 00′ E, such as Sicyonia scristata, Processa japonica and Ibacus novemdentatus. There were no sharp boundaries in the species spatial distributions between the two shrimp assemblages, however, with differ- ences in the species concentrative areas.