Correlation and path coefficient analysis between morphological traits and body weight in Amphiprion ocellaris

【Objective】The aim of this study was to investigate the relationship between body weight and morphological traits in Amphiprion ocellaris under aquaculture condition.The multiple regression equations of body mass and main morphological characters were established to provide a useful reference for the fast-growing selective breeding of A.ocellaris.【Method】In the experiment, individuals of two-month-old A.ocellaris were randomly collected, and body weight(W), total length(L₁), body length(L₂), body height(L₃), head length(L₄), head height(L₅), snout length(L₆), caudalpeduncle length(L₇), caudal-peduncle height(L₈), pre-dorsal length(L₉), pre-pectoral length(L₁₀), pre-pelvic length(L₁₁), pre-anal length(L₁₂) were accurately determined.The correlation coefficients between each trait were calculated by correlation analysis, and the morphological traits that significantly affected body weight were selected by the path analysis method.The multiple regression equation between morphological traits and body weight was constructed by multiple regression analysis to analyze the influence of morphological traits on body weight in A.ocellaris.【Result】The results showed that there was extremely significant correlation among the 13 traits(P< 0.01).Body height had the highest correlation coefficient(0.965) with body weight, followed by body length(0.944), and snout length(0.730) and caudal-peduncle length(0.601) had low correlation coefficient with body weight.After eliminating the collinearity effect, the path analysis selected five morphological traits with significant effect on body weight, which were body height, caudal-peduncle height, body length, head length and snout length.The order of direct effect on body weight(path coefficient) from large to small was body height(0.574) > body length(0.404) > caudal-peduncle height(0.284) > snout length(0.108) > head length(-0.358), the order of indirect effect(indirect path coefficient) from large to small was head length(1.256) > caudal-peduncle height(0.667) > snout length(0.621) > body length(0.540) > body height(0.391), and the order of individual determinant coefficient from large to small was body height(0.330) > body length(0.163) > head length(0.128) > caudal-peduncle height(0.081) > snout length(0.012).The multiple regression equation between body weight and these five morphological traits was W=-0.708+0.085L₃+0.084L₈+0.025L₂-0.090L₄+0.070L₆, R²=0.963.【Conclusion】Body depth is the most important morphological index in the selective breeding of fast-growing parent fish of 2-month-old A.ocellaris.Other variables such as body length, head length, snout length and caudal-peduncle height can be used as auxiliary selection indexes.