Principal component and discriminant analyses of traits of Siniperca chuatsi at different ages
In order to research the early-stage growth of morphological traits of Siniperca chuatsi and judge the age matching with the size of S. chuatsi missing the best growing season, data of body mass, total length, body length, body depth, head length, eye diameter, tail length, caudal peduncle length, caudal peduncle depth were collected from S. chuatsi at 2 to 6 months of age in this study. The morphological traits were analyzed by principal component and dis-criminant analysis. The results showed that there are different degrees of correlation among all the morphological traits at different age phases, the relationships between body mass and total length and body length and body depth are rela-tively higher, and that between eye diameter and other traits is relatively lower. The first principal component always reflects the growth and development of S. chuatsi at all the age phases. The second principal components of S. chuatsi at different months of age are different. The second principal component reflects the development of eyes from 2 to 4 months of age, while that reflects the development of head and tail at 5 and 6 months of age, respectively. The month age closely related to the size of S. chuatsi which has missed the best growing period can be typed by employing the discriminant equations established in this paper, the method is stepwise discrimination analysis and the result shows 98.87%of accuracy. The body length-mass relation equation is W=2.58×10–2L2.9985(R2=0.994) in the early stage of S. chuatsi, which demonstrate that the body mass and length of S. chuatsi grow in similar velocity. This study proved that body mass, body length and body depth are the most important morphological traits in the early growth stage of S. chuatsi, established the discriminant equations in the early growth stage of S. chuatsi, demonstrated that the body mass and length of S. chuatsi grow in similar velocity. This paper provides theoretical evidence and perfect measure targets for breeding of S. chuatsi in the early growth stage in aquaculture.