Comparison of morphological traits of hybrid groupers (Epinephelus coioides♀×E.akaara♂) and their parents

We measured the body mass and seven morphometric traits of hybrid groupers (Epinephelus coioides♀×E.akaara♂) and their parents to analyze the relationship between morphometric traits and body mass using path analysis, and then obtained multivariate regression equations. The results show that the correlation coefficients between body mass and morphometric traits have very significant difference in all three groupers (P < 0.01). The total length and body mass had the highest correlation coefficient both in E.coioides and E.akaara, being 0.946 and 0.932, respectively. But for hybrid groupers, the highest correlation coefficient was between caudal peduncle depth and body mass (0.955), and the correlation coefficient between total length and body mass was 0.927. The multivariate regression equation of E.coioides retained standard length, body height, caudal peduncle depth and body width. The multivariate regression equation of E.akaara retained total length, body height and caudal peduncle depth. The multivariate regression equation of hybrid groupers retained total length, body height, caudal peduncle depth and body width. The analysis of heterosis in hybrid groupers found obvious average heterosis, while the negative (compared with male parents) and positive (compared with female parents) heterobeltiosis were found in hybrid groupers. The average heterosis of hybrid groupers in body mass and standard length were 3.43% and 3.02%, respectively. It is revealed that the difference between hybrid groupers and female parents is less than the difference between that and male parents, and the hybrid groupers resemble female parents in morphological traits.