Effects of shell morphological traits on the weight traits of Manila clam (Ruditapes philippinarum)
Abstract The shell length, height, and width, live body weight, and edible tissue weight of Manila clam of 1, 2, and 3 years of age were measured, and their correlation coefficients were calculated. The shell morphological traits were used as independent variables, and live body weight or edible tissue weigh used as a dependent variable for calculating the path coefficients, correlation index and determination coefficients. The results showed that the correlation coefficients between each shell morphological trait and the live body weight or edible tissue weight were all highly significant ( P R 2 ) of morphological traits against the live body weight of clams of all ages and edible tissue weight of 1-year-old clams were larger than 0.85, but R 2 of morphological traits against the edible tissue weight of 2- and 3-year-old clams was smaller than 0.85, indicating that some other factors might be associated with the edible tissue weight of 2- and 3-year-old clams. Multiple regression equations were obtained to estimate shell length X 1 (cm), shell height X 2 (cm), shell width X 3 (cm) against live body weight Y (g), edible tissue weight Z (g): for 1-year-old clams: Y  = −4.317 + 0.18 X 1  + 0.147 X 2 , ( X 1 X 2 Z  = −1.011 + 0.095 X 2 , ( X 2 Y  = −15.119 + 0.249 X 1  + 0.176 X 2  + 0.688 X 3 , ( X 1 X 3 Z  = −4.248 + 0.198 X 1 , ( X 1 X 3 Y  = −25.013 + 0.415 X 1  + 1.184 X 3 , ( X 1 X 3 Z  = −7.082 + 0.119 X 1  + 0.332 X 3 , ( X 1 X 3