Species identification of Loliginidae inhabiting the East China Sea based on beak

Based on 69 samples of Loligo chinensis and 100 samples of Uroteuthis duvauceli collected in Luchaogang in November of 2015, the paper studied the species identification between L. chinensis and U. duvauceli by principal component analysis, stepwise discriminate analysis and Fourier analysis. Results showed that there were highly significant differences in the 12 morphological parameters of beak between two species. There were also significant differences between male and female U. duvauceli. The total successful discrimination rate for L. chinensis andU. duvauceli by stepwise discriminate analysis was 88.2%. The total successful discrimination rate for L. chinensis and U. duvauceli based on the result of principal component analysis was 90.1%. The total successful discrimination rate for male L. chinensis and male U. duvauceliwas 83.3%. The total successful discrimination rate for female L. chinensis and female U. duvauceli attained 97.8%. The total successful discrimination rate for L. chinensisand U. duvauceli based on the upper beak by Fourier analysis was 83.3%. The total successful discrimination rate for L. chinensis and U. duvauceli based on the lower beak by Fourier analysis reached 95%.