台湾南湾区秋末冬初海樽类的种类组成和数量分布

Species Composition and Abundance Distribution of Thaliacea in Late Autumn and Early Winter in the Nanwan Bay of Taiwan, China

根据 2001 年 11 月 2—3 日和 12 月 8—10 日在台湾南湾 12 个测站分别用 2 种圆锥形浮游生物网 (长180 cm，网口直径 45 cm，网目 333 μm 或 200 μm) 采集表层和底层的浮游动物样品，分析了南湾浮游海樽类的种类组成和数量分布，共鉴定海樽类 16 种，其中 7 种为台湾周围海域新记录。东方双尾纽鳃樽和小齿海樽为优势种。南湾海樽类的种类数及个体数量均以 12 月多于 11 月。讨论了水文条件与海樽类时空分布的关系，认为外海高盐水团是南湾冬季海樽类生态特征的主要制约因子。典型的高温高盐种大西洋火体虫、长吻纽鳃樽、安纽鳃樽、多手纽鳃樽、韦氏纽鳃樽、羽环纽鳃樽和斑点纽鳃樽等可以作为外海高温高盐水入侵南湾的指标种。与邻近海域比较，秋冬季南湾与台湾岛以东海域海樽类的区系特征比与台湾海峡和南海北部更加相似。

A zooplankton survey was carried out in November 2-3 and December 8-10, 2001 at 12 stations in the Nanwan Bay of Taiwan, China. Altogether 92 quantitative zooplanktonic samples are collected from subsurface water layer and bottom layer with tow conical plankton nets (180 cm in length, 45 cm in mouth diameter, 333μm or 200μm in mesh size). A total of 16 species of Thaliacea are indentified, among which 7 species aere new records in the waters around Taiwan. These species are dominated by Thalia democratica orientalis and Doliolum denticulatum. The species number and abundance of Thaliacea in December are more than that in November. This relationship between temporal and spatial distribution of the Thaliacea and their hydrologic conditions have been discussed. While in winter, the outshore hyperhyline water mass is the main factor influencing the ecological feature of populations. Among the typical high temperatum and high salinity species of Thaliacea are Pyrosoma atlanticum, Brooksia rostrata, iatteriella amboinensis, Traustedtia multitentaculata, Weelia cylindrical, Cyclosalpa pinnata and Ihlea punctata and so on, which might taken as one of the indicators influencing off-sea high temperature and high salinity water masses. A comparison of the Thaliacea off Nanwan Bay with neighbouring waters shows that the former fauna is much closely related to the east waters of Taiwan Island than to the Taiwan Straits and northern South China Sea in autumn and winter.