Abstract:Thamnaconus septentrionalis is a common economic marine fish species that can be found in coastal waters of China. The artificial breeding technique has been established for T. septentrionalis. In order to optimize artificial culture techniques and to promote industrialization of T. septentrionalis, path analysis was conducted to investigate the effects of morphological traits on body weight. According to body weight, the samples were divided into 3 groups (small size, medium size, and large size). Full length (FL), body length (BL), body height (BH), head length (HL), snout length (SL), eye diameter (ED), caudal peduncle length (CL), caudal peduncle height (CH), and body weight(BW) of T. septentrionalis were measured. We calculated the correlation coefficients, path coefficients and determination coefficients. The regression equations with morphological traits as variables and body weight as the dependent variable at each size were established. The results showed that the morphological traits affecting body weight at different sizes were different. Body height, body length, eye diameter, and caudal peduncle length were the significant traits affecting body weight at small sizes; for medium T. septentrionalis, the morphometric traits that significantly affected body weight were body length, caudal peduncle height, head length, body height, full length, and caudal peduncle length; for large T. septentrionalis, the significant traits were body height, full length, and caudal peduncle height. The regression equations for small, medium and large size: Y=–84.753+17.263XBH+6.572XBL–28.928XED–11.353XCL; Y=–325.824+20.321XBL+94.047XCH–11.425XHL +15.713XBH–7.218XFL+15.744XCL; Y=–516.433+38.012XBH +10.545XFL+82.752XCH. The sums of the coefficients of determination at each size were all greater than 0.85. This indicates the main morphological traits affecting body weight were found. This study can serve as a valuable tool to improve the culture industry of T. septentrionalis.
