The dominant species of euphausiids in the East China Sea and their ecological daptability

The aim of this paper is to study the ecological characters of the dominant species of Euphausiids in the East China Sea. Four oceanographic cruises were conducted in the East China Sea during the period 1997-2000. Altogether four dominant species of Euphausiids were recorded in the Ease China Sea, Euphausia nana Brinton, Euphausia pacifica Hansen, Pseudeuphausia sinica Wang et Chen, and Pseudeuphausia latifrons (S.O. Sars). They were categorized according to their habitat conditions into two groups, temperate, sub-tropical and tropical species. During the winter and spring periods, the community is dominated by temperate species, E. nana and E. pacifica. Their densities peak in the spring for E. nana, winter for E. pacifica, respectively, and are low in the summer and autumn during which E. pacifica is not even represented. The dominant species during the summer and autumn are P. sinica and P. latifrons, both of which are represented in low density in the winter and peak in the autumn. The sub-tropical and t