Correlation between morphological traits and body weight in 10-month-old corvina lobsters（Panulirus homarus） and path analysis

【objective】 To analyze the influence of morphological traits on the body weight of 10-month-old corrugated lobster(Panulirus homarus), and to provide reference for the selection and breeding of excellent morphological traits in corrugated lobster.【Method】Body weight(Y) and seven morphological traits of body length(X₁), cephalothorax length(X₂), cephalothorax width(X₃), cephalothorax height(X₄), abdominal length(X₅), first abdominal width(X₆) and first abdominal height(X₇) were measured in 51 10-month-old corvina lobsters, and the interrelationships between morphological traits and body weight of 10-month-old corvina lobsters were analyzed by multiple regression, and the main influencing traits of body weight were identified by correlation analysis and path analysis. The regression equation of morphological traits on body weight was established by using multiple regression analysis, and the best-fit curve model was selected by combining stepwise regression analysis.【Result】There was extremely significant correlation among all seven morphological traits(P<0.01, the same below) and between the seven morphological traits and body weight in 10-month-old corvina lobsters. Among them, the effects of body length(X₁), cephalothorax length(X₂) and cephalothorax height(X₄) on body weight were all significant(P<0.05) or extremely significant, and the sum of the direct and indirect coefficients of these three morphological traits on body weight was 0.941, which was greater than 0.850, indicating that the body weight of corvina lobsters was mainly determined by these three morphological traits together. The regression analysis established a multiple regression equation for morphological traits on body weight:Y=-444.692+1.141X₁+ 5.943X₂+2.347X₄. The three morphological traits retained in the regression equation, namely X₁, X₂ and X₄, were fitted with body weight separately. The results of the 10 curve models were extremely significant, indicating that the models obtained by curve fitting were meaningful. From the fitting results, the best-fit models of X₁, X₂ and X₄ for body weight were exponential, cubic and power functions with the equations Y=9.344e^0.018i>X₁, Y=-0.029X₂²+0.001X₂+61.131 and Y=0.3X₄^2.35 respectively, corresponding to R² of 0.892, 0.936 and 0.805 respectively.【Conclusion】Body length, cephalothorax length and cephalothorax height have significant effect on the body weight of the corrugated lobster. When using body weight as the main indicator for fry breeding and parental selection, cephalothorax length should be the main selection trait, with body length and cephalothorax height as secondary selection traits.