Effects of morphological traits on body mass of Changfeng silver carp (Hypophthalmichthys molitrix) at different ages

To study the influence of morphological characteristics of Changfeng silver carp (Hypophthalmichthys molitrix) on its growth, we applied the principal component analysis and path analysis methods to analyze the conventional morphological measurements and truss network. The results show that the correlation coefficients between the morphological traits and body mass were extremely significant at different ages (P<0.01). Besides, the correlation coefficients between them were also different at different stages. Principal component analysis revealed that 6- and 12-month old H. molitrix showed a synergistic growth, as well as development of the overall structure, but it was mainly the growth of the trunk at 36-month age. Path analysis shows that the path coefficients of three morphological traits (x₈, x₁₁, x₁₃) for the body mass were significant at three stages (P<0.05), and these traits had significant impacts on the body mass at all stages. The optimal regression equations of morphological traits to body mass were established for the three groups. The effects of morphological traits on the body mass were distinct at different stages. The results suggest that the total length, body length and body height should be selected as the breeding targets for H. molitrix at early growth stage. However, the target trait for selective breeding of adult fish should mainly be total length, and the synergistic breeding of fish body width should be emphasized.