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Vol. 49 No. 4, 2010
Unexpected Dominance of the Subtropical Copepod Temora turbinata in the Temperate
Changjiang River Estuary and Its Possible Causes
Guang-Tao
Zhang1, Song Sun1,*, Zhao-Li Xu2, and
Qi-Long Zhang1
1Institute
of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
2East China Sea Fisheries Research Institute, Chinese
Academy of Fisheries Sciences, Shanghai 200090, China
Guang-Tao Zhang, Song Sun,
Zhao-Li Xu, and Qi-Long Zhang (2010)
The zooplankton community in the Changjiang (Yangtze) River estuary
(CRE) was sampled quarterly in 2004, the 1st yr after the Three Gorges
Reservoir was impounded to a water level of 135 m, in order to
investigate possible changes in the community structure after
freshwater control upstream at the dam. Zooplankton assemblages
were consistent with previous studies in all seasons except
summer. A tropical-subtropical copepod species, Temora turbinata,
was found to be the most abundant zooplankton species in this area for
the 1st time in Aug. 2004, while previously dominant species, such as Calanus sinicus, Euchaeta concinna, and Labidocera euchaeta, decreased in
abundance and appearance frequency. From historical data, T. turbinata
was never dominant in this area before 2003. It was present only
in summer, in accordance with the northerly invasion of the Taiwan Warm
Current (TWC). In this study, the range of the Changjiang River
Diluted Water was found to have shrunk in summer, and the TWC occupied
a larger area of both the bottom and surface layers, compared to the
long-term average. Our results indicate that T. turbinata
in the CRE area was recruited from the southern part of the East China
Sea by the TWC. Its unexpected dominance suggests a northward
extension of warm-water species resulting from global warming, although
it appeared immediately following water control at the Three Gorges
Reservoir.
Key words: Temora turbinata, Three Gorges
Reservoir, Taiwan Warm Current, Global warming, Northward extension.
*Correspondence: Tel: 86-532-82898598. Fax:
86-532-82868008. E-mail:sunsong@qdio.ac.cn
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