Planktonic copepods (Crustacea: Copepoda) are well known by the most dominanttaxonomic group in marine zooplankton both by species number and numericalabundance. 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.Trawl fishery is one of very important local economic activities in Taiwan. Productionfrom the northeastern waters off Taiwan, especially trawl fishery landings fromsurrounding waters of Kuei-Shan Island is not only abundant but sustainable all the yearround. To know how the fishery will go on, the long-term investigation and monitoringon planktonic copepods should be one of the best ways we need to do. The Kuroshioflows northward along the eastern ocean off Taiwan. It has a very significant influenceon the distribution of marine life, especially the planktonic animals. How the Kuroshioinfluences dispersal patterns of species in this waters, any improvement of the knowledgeabout the planktonic copepods undoubtedly will have a positive input on theunderstanding of seasonal fluctuation pattern in the local important fishery.Planktonic copepod samples will be collected by Ring Trawl Net at nine fixed sites ofsurrounding waters of Kuei-Shan Island. The various hydrological data will be obtainedsimultaneously by a CTD device at each site of all the four cruises.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.