Growth and seasonal changes in size structure of clam, Gomphina veneriformis
You Zhongjie, Wang Yinong, Yan Zhengrong Guo Shen (Ningbo Branch of Zhejiang Fisheries College, Ningbo, 315010)
Seasonal changes of the size composition and growth of clam Gomphina veneriformis (Lamarck), population in the intertidal zone of Zhujiajian Island (122°20′E,29°54′N) were studied. The samples were monthly collected during the period from Dec. 1987 to Dec. 1988. The size composition and growth rate were analysed by the method using probabilily paper based on the frequency distribution of shell length in each sample. The recruits appeared in August, in all age groups, the growth continued from Apr. to Oct.. The regression equations of shell length (L, cm) to shell high (H, cm), to shell wide (B,cm) and to total body weight (W, g) are below:L=0.0780+1.290 OH (r=0.9914)L=0.3199+2.4239B (r=0.9868)W=0.1916L~(3.0784) (r=0.9967)The precentage of drain body weight (=drain body weight/shell weight) and the precentage of fresh body weight(=fresh body weight/total weight) show regular variation. Beside, the method of age-determination and body water content are disscussed.