Mathematical analysis of effects of morphometric attribute on body weight of largemouth bass (Micropterus salmoides).

The effects of morphometric attributes on body weight of largemouth bass were analyzed.Data of total length(X1),standard length(X2),body depth(X3),body width(X4),interorbital distance(X5),head length(X6),snout length(X7),caudal peduncle length(X8),caudal peduncle depth(X9) and body weight(Y)were collected from culture pond in this study.Correlation analysis,path analysis and multiple regression were used.The correlation coefficients among the morphometric attributes were calculated,then the total length,body depth,head length and caudal peduncle depth were eliminated from the variable data,because all of them were co-linear with standard length.Snout length and caudal peduncle length were also kicked out from the variable data because of no significance in multiple regression equation.The three morphometric attributes(X2,X4,X5) were used as independent variables,and body weight(Y) was used as a dependent variable for path analysis.Path coefficients(Py.x),determination coefficients(dy.x) and correlation index(R2) were calculated in path analysis.The results showed that the three independent variables significantly affect body weight with correlation coefficient 0.942,0.979,0.928(P0.01) respectively.The path coefficients(Py.x) of the body width,standard length and interorbital distance to the body weight have all reached a level of significance.These attributes were very indicative of determining the body weight,among them the body width weighted the most(P4 = 0.599) to the body weight,it was a key effective factor,and standard length and interorbital distance weighted the second and the third(P2 = 0.231,P5 = 0.189).Judged from the results of high correlation index(R2 = 0.980),the main variables(X2,X4,X5) have been selected.We have obtained the multiple regression equation to estimate the body weight as LgY = 1.065 + 0.765 LgX2+ 1.441 LgX4 +0.543 LgX5.This paper provides theoretical evidence and perfect measure target for selective breeding of largemouth bass.