農業部-水產試驗所全球資訊網農業部-水產試驗所全球資訊網

本研究調查 2004 年 2 月至 2005 年 10 月期間台灣南部海域海樽種類組成及數量的時空分布，並探討海樽種類組成與水文環境之相關性。綜合採樣分析結果，共鑑定出 3 科 10 屬 18種海樽，平均豐度為152 ± 33 ind. 100 m^-3。海樽豐度有明顯的季節變化，以冬季較高。前五個優勢種依序為：Thalia rhomboides、Pyrosomella verticillata、Doliolum denticulatum、Thalia orientalis與 Thalia democratica，均屬於大洋廣布類群，佔所有海樽豐度的82%。世代比例以 T. democratic 及 D. denticulatum 的無性世代為多，其餘均以有性世代比例較高。本海域海樽總豐度與溫度呈顯著負相關，不同優勢種與環境因子各有不同的相關性，T. rhomboides、D. denticulatum 及 T. orientalis與溫度呈顯著負相關。台灣南部海域之海樽豐度及水文環境因子均有明顯的季節變化，測站間則無顯著差異。優勢種組成於水團間之變異不大，顯示本研究海域水團對海樽族群的影響不大。

This study investigated the spatial and temporal distribution in species composition and abundance of thaliaceans (Tunicata) in relation to environmental factors in the waters off southern Taiwan between February 2004 and October 2005. In total, 18 thaliacean taxa belonging to 10 genera and 3 families were identified, with the mean abundance of 152 ± 33 ind. 100 m^-3. The abundance of thaliaceans showed a clear seasonal change, higher in winter. The five most dominant species were Thalia rhomboides, Pyrosomella verticillata, Doliolum denticulatum, T. orientalis and T. democratica. They were widespread oceanic species, and together constituted 82% of the total thaliaceans. The abundance of thaliaceans showed significant negative correlation with temperature. Different predominant thaliacean species showed different correlationship with environmental factors; T. rhomboides, D. denticulatum and T. orientalis were significant and negatively correlated with temperature. Result of ANOVA test revealed that the abundance of thaliaceans and hydrography had significant seasonal differences in the waters off southern Taiwan, but showed no significant difference among stations. The species composition of dominant thaliacean among the water masses was similar, implied that the influence of water masses on the distribution of thaliaceans was minor.