Abundance and distribution of Appendicularia in the East China Sea

Based on the data of four seasonal investigations in the East China Sea(23°30′-33°N,118°30′-128°E)from 1997 to 2000,the distribution and the seasonal changes of Appendicularia abundance,their dynamics and relationship with fishing grounds were discussed.The results indicated that the total abundance of Appendicularia peaked in autumn with an average value of 149 ind./100m~3,38 ind./100m~3 in summer,20 ind./100m~3 in winter and 9 ind./100m~3 in spring.The total abundance in spring,summer and winter showed no significant correlation with water temperature and salinity,while the abundance had significant positive correlation with surface water temperature in autumn.Appendicularia is characterized by warm water species.It was found that the formation of characteristics had a close relation with the dominant species adapting to different temperatures and salinity.The variation of Appendicularia abundance was closely linked with ebb and flow of warm current in the East China Sea.Its peak abundance in autumn also associated with the stay of warm current from summer to autumn.The occurrence of high abundance area of appendicularians in autumn in warm current waters such as Tsushima and Kuroshio plays an important role in forming the fishing grounds for Navodon septentrionalis in the north of offlying sea and Scomber japonicus and Trichiurus lepturus in the south of offlying sea.