Analysis of Effects of Morphometric Traits on Body Weight of Yellow Catfish Pelteobagrus fulvidraco

To study the effects of morphological attributes on body weight(Y) of yellow catfish, 526 fry 100 days after hatch individuals were sampled for measuring seven metric traits, including the total length(X1), body length(X2), caudal peduncle length(X3), caudal peduncle depth(X4), body depth(X5), head length(X6) and head breadth(X7). The relationship between morphological attributes and body weight(Y) was quantified by correlation analysis, path analysis and multiple regression analysis to determine the major morphological attributes. Caudal peduncle length(X3) was eliminated from the variable data set because it was non-significant with body length. Seven metric traits were used as independent variables, and body weight(Y) was used as a dependent variable for path analysis. Path coefficients, determination coefficients and correlation index were calculated in path analysis. The results showed that all seven correlation coefficients between each metric traits and the weight achieved were all very significantly different(P 0.01). The path coefficients except caudal peduncle length(X3) to the body weight(Y) all reached a level of significance. These attributes were very indicative of determining the body weight(Y). Judging from the result of high correlation index(R2=0.915), direct effect and the indirect effect, total length(X1), body length(X2) and head length(X6) were selected, and the body length(X2) was key effective factor on body weight(Y).