Grey relational analysis between early morphological traits and body weight of Trachinotus ovatus bred in pond

ObjectiveThe main morphological traits affecting the body weight of Trachinotus ovatus were deter-mined to provide important technical parameters for artificial breeding of it.MethodA total of 383 T. ovatus populations were randomly selected from three different growth stages of pond culture,including 45,65 and 110 days post hatching (DPH). Grey relational analysis was used to analyze correlation degree between ten morphological traits(total length, body length,body height,head length,head height,rostrum length,eye diameter,post-eye head length,caudal pedun-cle length and caudal peduncle height) and body weight so as to evaluate the relative importance of each morphological trait on body weight.ResultThere were certain differences in gray correlation between morphological traits and body weight of T. ovatus at different growth stages. The grey relational degrees between morphological traits and body weight of 45 DPH was 0.709-0.854. The descending relational order of the morphological traits was:body length>total length>body height>head length>post-eye head length>caudal peduncle height>head height>eye diameter>caudal peduncle length>rostrum length. The grey relational degrees between morphological traits and body weight of 65 DPH were in the interval of 0.788-0.904. The descending relational order of the morphological traits was:body length>total length>body height>head height>head length>caudal peduncle height>caudal peduncle length>post-eye head length>rostrum length>eye diame-ter. The grey relational degrees between morphological traits and body weight of 110 DPH was in 0.674-0.826. The descen-ding relational order of the morphological traits was:body length>body height>total length>head length>post-eye head length>caudal peduncle height>head height>eye diameter>rostrum length>caudal peduncle length. The correlation coeffi-cient between morphological traits and body weight of T. ovatus reached extremely significant level at each growth stage (P<0.01),and top three morphological traits with the highest correlation were total length,body length and body height.ConclusionAmong all the morphological traits of T. ovatus at various growth stages,the relational degree between body length and body weight is the highest,and that of total length and body height is the second. Therefore,body length and body height can be set as the indirect morphological traits for body weight in T. ovatus breeding.