Study on the biological oceanographic characteristics of planktonic copepods in the waters north of Taiwan, China Ⅰ.Abundance distribution

Based on the investigation materials of 6 cruises in the waters north of Taiwan,OW a from 1987-1990,the abundance distribution characteristics of planktonic copepods are discussed.The results show that the highest abundance of copepods occurs in spring and the lowest one in winter,while the abundance in summer and autumn is between the above two seasons.The copepod abundance in inside of the Kuroshio front is higher than that in outside of the front.There is a distribution tendency that higher abundance occurs in outshore area in summer and in nearshore area in winter,which corresponds with the trend of seasonal swings of the Kuroshio front.The higher copepod abundance appears generally in mixed areas of various water masses,especially in nearshore side of upwelling of the Kumshio subsurface water.However,in the Kuroshio subsurface main water,the abundance is low because of some factors such as law concentration of dissolved oxygen and so on.The vertical distribution trend is that the copepod abundance decreases with increase of depth,and the diurnal vertical migration regularities of some species are probably the one of reasons that cause the abnomal distributions in some local waters.