Planktonic copepods (Crustacea: Copepoda) are well known by the most dominanttaxonomic group in marine zooplankton both by species number and numericalabundance. They mainly feed substantially on phytoplankton, nanoplankton andmicroplankton, and in the meantime are the major prey to the macroplankton,ichthyoplankton, and even certain fishes, sea birds and marine mammals are their directpredators. They therefore form an important link in the marine food chain. Theseasonal fluctuation of abundance and distribution of planktonic copepods is highlyrelative to the hydrology of marine environments. Certain copepod species are knownto be indicator of water masses and certain currents. Reasons for these characteristics,copepods are more or less become the major subject of investigations conducted byfishery biologists as well as biological oceanographers.Trawl fishery is one of very important local economic activities in Taiwan.Production from the northeastern waters off Taiwan, especially trawl fishery landingsfrom surrounding waters of Kuei-Shan Island is not only abundant but sustainable allthe year round. To know how the fishery will go on, the long-term investigation andmonitoring on planktonic copepods should be one of the best ways we need to do. TheKuroshio flows northward along the eastern ocean off Taiwan. It has a very significantinfluence on the distribution of marine life, especially the planktonic animals. How theKuroshio influences dispersal patterns of species in this waters, any improvement of theknowledge about the planktonic copepods undoubtedly will have a positive input on theunderstanding of seasonal fluctuation pattern in the local important fishery.The research vessel Hai-Chien will be commissioned to conduct the seasonal samplingsurvey of marine zooplankton in this project. Planktonic copepod samples will be collected by Ring Trawl Net at five fixed sites along one latitudinal transect extendingfrom eastern coastal waters off Taiwan eastward the open sea. The various hydrologicaldata will be obtained simultaneously by a CTD device at each site of all the four cruises.These data are required for analyzing the relationship between copepod distribution andthe hydrological factors.Primary objectives of this project are to analyze the relationship between copepoddistribution and hydrological factors, to identify indicator species of water masses, tomonitor the fauna of marine planktonic copepods off northeastern Taiwan, and todiscover the link between copepod fluctuation and the trawl fishery.