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Vol. 47 No. 1, 2008
Monsoon-Driven Succession of Copepod Assemblages in Coastal Waters of the Northeastern Taiwan Strait
Li-Chun Tseng1, Ram Kumar1, Hans-Uwe Dahms1, Qing-Chao Chen2, and Jiang-Shiou Hwang1,*
1Institute of Marine Biology, National Taiwan Ocean University, Keelung 202, Taiwan
2South China Sea Institute of Oceanography, Academia Sinica, Guangzhou 510301, China
Li-Chun Tseng, Ram Kumar, Hans-Uwe Dahms, Qing-Chao Chen, and Jiang-Shiou Hwang (2008)
Monsoon winds (a southwesterly (SW) monsoon during summer and a
northeasterly (NE) monsoon during winter) were shown to play pivotal
roles in shaping species richness and diversity of planktonic organisms
in the water masses of the Taiwan Strait (TS). We investigated
monsoon-related variations in copepod assemblages in the northeastern
TS from Aug. 1998 to May 1999 on 4 research cruises. Our data provide
basic information for the biological monitoring of the TS, using
improved index measurements. In total, 36 copepod species belonging to
21 genera and 14 families were identified. The abundance of Calanoida
showed a negative correlation with salinity (r = -0.381, p = 0.011, Pearson's product moment correlation) and a positive correlation with temperature (r = 0.662, p <
0.001, Pearson's product moment correlation). Application of the
indicator value index proposed by Dufrêne and Legendre indicated that
cold-water species become dominant in this region only when the NE
monsoon weakens and retracts from the southern part of the TS.
Regardless of the seasonal succession, the calanoid copepod,
Acrocalanus gibber, was the dominant species with a mean density of
3868 individuals (ind)/1000 m3 (with a relative abundance of 36.5%), followed by Acartia erythraea with a mean density of 1874 ind/1000 m3 (17.7%), and by Labidocera euchaeta with a mean density of 1178 ind/1000 m3
(11.1%). Four copepod communities were distinguished prior to the
advent of the NE and SW monsoonal winds and during the peak periods of
the respective monsoons. Our results also reveal the influence of the
Kuroshio Branch Current in the study area on copepod assemblages, with
temporal successions being determined by the SW and NE monsoonal winds.
Key words: Copepod assemblages, Taiwan Strait, Monsoon, Kuroshio Branch Current.
*Correspondence: E-mail:Jshwang@mail.ntou.edu.tw
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