Ecological characteristics on macro—medium planktonic copepods in the subtropical circulation zone east of Taiwan Island

The abundance distribution and ecological characteristics of planktonic copepods are analyzed.Their relations to the environmental factors are discussed based on data obtained from 4 cruises during a multidisciplinary survey in the waters under the subtropical circulation zone east of Taiw an Island from 1995 to 1997.The results show that the macro-medium planktonic copepods in this region is the characteristics of low abundance (four seasons average 6.75 cells/m³), low dominance (Y< 0.131) and low seasonal variations.A total of 206 copepod species recorded coexisted respectively to 5 ecotypes.It is suggested that these ecotypes were dynamically governed by different water masses nevert heless, the tropical oceanic group was consistently dom inated.