鮸形态性状与体质量的关系

Relationship between morphological traits and body mass of Miichthys miiuy

为了研究鮸的形态性状与体质量之间的关系,测量了524尾12月龄左右鮸的体质量(Y,g)和8个形态性状(cm),包括全长(X_1)、体长(X_2)、头长(X_3)、躯干长(X_4)、尾长(X_5)、尾柄长(X_6)、尾柄高(X_7)和体高(X_8).采用相关分析、回归分析、通径分析以及模型拟合等方法对其进行分析.结果表明:鮸所有性状两两之间存在极显著正相关关系,相关系数在0.834~0.941.经共线性诊断排除了体长这一具有严重共线性的性状后,采用逐步引入-剔除法进行多元回归并进行显著性检验,成功筛选出全长(X_1)、躯干长(X_4)、尾柄高(X_7)和体高(X_8)4个统计检验极显著的形态性状,并建立多元回归方程:Y=-444.188+7.943X_1+12.861X_4+38.254X_7+42.722X_8.通径分析结果显示,4个形态性状中,体高对体质量的直接作用最大(通径系数=0.351),全长次之(通径系数=0.335).对全长和体高与体质量之间的函数关系进行曲线模型拟合得出,在6个拟合模型中,幂函数模型拟合效果最好,方程为:y=0.013 x^(2.891)(全长);y=2.028x^(2.751)(体高).经适合性检验得知,全长比体高通过幂函数对体质量的预测效果更好.研究结果可为鮸的形态性状在选择育种中的有效利用提供重要参考.

Miichthys miiuy Basilewsky is a commercially important marine fish in China. To understand the relationship between body mass and morphometric traits of M. miiuy, body mass （Y, g） and other eight morphometric traits （cm）, e.g., total length （X1）, body length （X2）, head length （X3）, trunk length （X4）, tail length （X5）, tail handle length （X6）, tail handle height （X7）, and body height （X8） of 524 individuals of about 12monthold M. miiuy were measured in this study. The methods of correlation analysis, multiple regression analysis, and path analysis were used to analyze the data. Also, the best model reflecting the relationship between morphometric traits and body mass were obtained through model fitting screening. The results showed that the correlation coefficients between every two traits ranged from 0.834 to 0.941, and all reached significance level （P〈0.01）. And body length was ruled out from the multiple regression analysis by the method of multicollinearity diagnosis. We established a regression equation using the rest morphologi-cal traits as variables and body mass as dependent variable, in which direct and indirect path coefficients and determinant coefficients were calculated. Four morphometric traits achieved highly significant levels （P〈0.01）, and they were the main decisive morphometric traits linked to body mass. The multiple linear regression model equation was established as Y=-444.188 ＋7.943X1＋12.861X4 ＋38.254X7＋ 42.722X8. Among them, the trait with the strongest direct effect on body mass was the body height （0.351）, then the total length （0.335）. In addition, the best model fitted for the individuals was y=0.013x^2.891 for total length, y=2.028x^2.751 for body height. The method of model fit test showed the accuracy of total length estimated body mass was higher than that of body height. This research may provide an important reference for the effective use of morphological traits for breeding of M. miiuy.