Copepod community structure in relation to hydrography in the East China Sea

• Main Authors: Guan-Ting Ou, 歐冠婷
• Other Authors: Chih-hao Hsieh
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/48170324023202710523

碩士 === 國立臺灣大學 === 海洋研究所 === 103 === Copepods link primary producers with organisms of higher trophic levels in marine food webs, and are crucial for sustainability of fisheries. The East China Sea (ECS) is an important fishery ground having diverse hydrographic conditions with complex circulation. It is necessary to understand the relationship between copepod communities and hydrographic conditions, and investigate the mechanisms shaping the community structures. This study aimed to describe the composition of copepods assemblages in the ECS, and explored the indicator species of water masses. We hypothesized that the copepod community structures correspond with water masses. Copepods composition and environmental data were collected from two cruises during June 2006 and January 2008 in the ECS. We defined water masses by T-S diagrams. The similarity of copepod communities among stations was explored by nonhierarchical clustering analysis (NHC). Redundancy analysis (RDA) through the forward selection procedure was used to investigate variance of copepods composition with important environmental factors of water masses. The indicator species analysis (IndVal) was applied to extract the indicator species of each water mass. We defined four and three water masses in the summer and winter cruises, respectively. During summer, community structures of the first NHC cluster corresponded with the water mass of the Taiwan Warm Current (TWC.s); while the second cluster was coincident with the Estuary (E.s). The first and second NHC clusters of community structures in the winter cruise corresponded with the TWC.w, and E.w, respectively. According to the indicator species analysis in summer, 9 species were the indicator species for the TWC.s, 2 species for the Mix.s2, and one species for the E.s. During winter, 12 species were the indicator species for the TWC.w, 2 species for the E.w, and only one species for the Mix.w. In this study, our results indicated obvious water mass-specific indication within copepods communities, and recognized the indicator species of specific water mass in the ECS.