Preliminary study of species identification of cephalopod in East China Sea and Yellow Sea based on beak morphology

Abstract:

Cephalopod beak has a stable structure, and it is a good material for species identification. According to the six species of cephalopod samples (Loligo chinensis,Uroteuthis duvauceli,Sepia pharaonic,Sepia kobiensis,Octopus ocellatus and Octopus variabilis) caught from East China Sea and Yellow Sea, the beak morphometrics are measured, discriminant analysis is made at family level, the results are compared between non standardization data and standardization data. The results showed that non standardization beak morphometrics of Loligo chinensis and Sepia pharaonic is bigger than Uroteuthis duvauceli and Sepia kobiensis, respectively,but the results are reversed after standardization data. Beak morphometrics of Octopus ocellatus is biggger than Octopus variabilis for both non standardization data and standardization data. Ten non standardization beak morphometrics were selected for the final discriminant analysis, and upper hood length (UHL), lower crest length(LCL), lower wing length (LWL) contribute most to the morphological variation,total successful discriminant rate is 92.8% for the three families; seven standardization beak morphometrics were selected for the final discriminant analysis,and upper hood length/mantle length (UHL/ML), lower crest length/mantle length (LCL/ML), lower wing length/mantle length (LWL/ML) contribute most to the morphological variation, and total successful discriminant rate is 98.1% for the three families. In conclusion, it can effectively improve the discriminant rate after data standardization for beak morphometrics.