Areal and seasonal distribution of heteropods in the East China Sea
2007
Xu, Z.L.(Chinese Academy of Fisheries Sciences, Shanghai (China))
This paper studies heteropods in terms of species composition, distribution and abundance, and analyzes the dominant species' contribution to the total heteropod abundance in the East China Sea by step-wise regression and other ecological indices based on data collected from four oceanographic cruises in the East China Sea (23 deg 30 min-33 deg N, 118 deg 30 min-128 deg E) during 1997 to 2000. A comparison was made between results from the present study and that of the year 1959. Eleven species were found in the above mentioned four oceanographic cruises during the research - 9 in autumn, 7 in summer, 2 in spring and only 1 in winter. Four species, namely Atlanta rosea, A. peroni, A. lesueuri and Protalanta souleyeti, are defined as 'common species' based on the fact that they were found all over the East China Sea. Others are thereby considered 'rare species', namely A. inclinata, Firoloida desmaresti, Atlanta sp., Oxygyrus keraudreni, A. turriculata, A. helcinoides and A. depressa. The analysis of regression contribution shows that of all heteropod species, A. rosea is the most important one, whereas the importance of A. peroni and A. lesueuri is revealed in autumn. By comparing data from 1959 with that from the present sampling period, an increase in the number of heteropod species could be observed. Taking into consideration the close reliance of heteropods on warm currents, they might serve as an effective indicator of warm current intrusion into the East China Sea.
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