Abstract:Black rockfish (Sebastes schlegelii) is an economically important marine fish. Our team constructed a three-generation breeding population of Sebastes schlegelii by combining population selection with family breeding. In order to understand the phenotypic correlation between the main morphological traits and body weight and the differences among the three-generation breeding population of S. schlegelii, the body weight (Y, g) and eleven other morphometric traits (cm), e.g., total length (X1), body length (X2), body height (X3), head length (X4), tail length (X5), caudal peduncle length (X6), caudal peduncle height (X7), tongue length (X8), trunk length (X9), eye diameter (X10), and head length behind the eyes (X11), were correlated on the three-generation continuous breeding population of 8-month-old S. schlegelii. Path analysis and gray correlation analysis were conducted to define the effect of major morphometric traits on body weight in the three-generation continuous breeding population. The results showed that all the correlation coefficients between morphometric traits and body weight achieved highly significant levels (P<0.01) or significant levels (P<0.05). The results of path analysis showed that the path coefficients between body height and trunk length were highly significant (P<0.01) in F1 and F2. The path coefficients of body height and caudal peduncle length were also highly significant (P<0.01) in F3. The multiple regression equation between the morphological traits and body weight for the three-generation breeding population were established as Y(F1)=−47.383+17.097X3+7.308X9, Y(F2)=−34.615+15.779X3+ 3.901X9, Y(F3)=−54.496+21.966X3+7.283X6. The results of gray correlation analysis showed that there was a certain difference in the size and order of the gray correlation between the body weight and morphological traits of the three-generation breeding population. However, the grey degree between body weight and body height, and the total length and body length, was the highest. The morphological traits affecting body weight were found to be different by two analytical methods, and there were obvious differences among the three-generation population. The first controlling trait was body height, indicating that body height is a predominant morphometric trait affecting body weight. This research may provide an essential reference for determining the measurement index of S. schlegelii in selective breeding.
