Effects of morphological traits on body mass of Culter mongolicus at different ages

【Objective】This study aimed to analyze the effects of morphological traits of Culter mongolicus at diffe-rent ages on body mass， thereby providing theoretical basis for improving breeding efficiency of this species.【Method】With 2-year-old and 11-year-old Culter mongolicus individuals as research subjects， morphological traits and body mass were measured using ruler， vernier caliper， and electronic balance. The mean， standard deviation， and coefficient of variation for each morphological trait of Culter mongolicus were calculated， and correlation analysis between body mass and morphological traits was performed using SPSS 19.0. Taking body mass as the dependent variable and each morphological trait as the independent variable， the optimal multivariate linear regression equation was established， and path coefficients and coefficients of determination were calculated.【Result】The coefficients of variation of body mass between the two age groups were the largest， with that of the 11-year-old group being 17.39% and that of the 2-year-old group being 23.31%. Except for trunk length， tail length， and caudal peduncle depth， the coefficients of variation for all other morphological traits in the 2-year-old group were larger than those in the 11-year-old group of Culter mongolicus. The correlation coefficient between body height and body mass was the highest in the 11-year-old group， while the correlation coefficient between full length and body mass was the largest in the 2-year-old group. The order of direct path coefficients of morphological traits affecting body mass in the 2-year-old group was full length > head length >body width， with full length having the greatest direct effect. In the 11-year-old group， the order was body height > full length > body width > distance between eyes > tail fin length， with body height having the greatest direct effect. The morphological trait with the largest direct coefficient of determination on body mass in the 2-year-old group was full length， while full length， body width， and head length were the main morphological traits affecting body mass. In the 11-year-old group， the trait with the largest direct coefficient of determination was body height， while body height， full length， body width， distance between eyes， and tail fin length were the main morphological traits affecting body mass.【Conclusion】Body mass is the core indicator for Culter mongolicus breeding， whose effects on morphological traits at different growth stages show an allometric pattern： Full length is the main influencing factor during the juvenile stage， while body height dominates during the adult stage. Full length and body width are key common traits affecting body mass of Culter mongolicus ，and demonstrate age stability.