On the parametric features of the spatial distribution of Sagitta enflata and Sagitta bedoti in the northern part of the East China Sea

Based on the Zooplanktonic data investigated in northern part of the East China Sea(from 27° to 32°30′N,westward 128°E) for four different seasons during 1997 to 2000,the relationship between the characters and seasonal change of Sagitta enflata Grassi and Sagitta bedoti Beraneck have been analyzed with distributive parameters such as K、α and β,furthermore,the spatial distributive characters of them have been analyzed with Taylor's and Iwao's method.These analyzed results showed that the spatial distribution of them was belonged to negative binomial distribution,and the highest concentration area of them was number 3 zone,both of them even distributed in most investigational zone in winter and spring.The Sagitta enflata concentrated in summer earlier than Sagitta bedoti which mainly concentrated in autumn,the highest value of congregation and quantity of Sagitta enflata appeared in different seasons,but these of Sagitta bedoti appeared only in autumn.