Multivariate Analysis of Morphological Varieties of Maxillary Barbell, Coreius guichenoti

Purpose For studying the effectiveness of fish classification based on fish morphological characteristics of fish species indexes.Method The study was conducted to measure the parameters such as the jaw palpus length, whole length, body length, head length, mouth width, eye diameter, mouth length, distance from the mouth to the front end of the pectoral fin base. Correlation, principal component analysis, regression analysis were the main research methods.Results The minimum of correlation coefficient was 0.59 and the maximum value was 0.99, which showed a strong correlation between the other seven morphological indexes of the Coreius guichenoti, except the eye diameter. Three principle components were selected from the principal component analysis. The cumulative contribution rate of the first principal component to the total variance was 77.42%; the cumulative contribution rate of the first two principal components to the total variance was 91.67%; the cumulative contribution of all three principal components to the total variance was 95.28%.The variation of the jaw palpus length had much correlation with the other measuring traits except the eye diameter. Among them, the principal component load value of the mouth length, whole length, head length and mouth width were higher, which showed similar characteristics of jaw palpus length variation. Regression equation was Y=26.68+1.29X1+0.010X2+2.05X3(R2=0.54); the principal component factors obtained for the remaining seven morphological traits except for the jaw length were shown in the scatter plot:most of C. guichenoti were divided into one cluster. The variation of the jaw palpus length had much correlation with the other measuring traits except the eye diameter. Among them, the principal component load value of the mouth length, whole length, head length and mouth width were higher, which showed similar characteristics of jaw palpus length variation.Conclusion The morphological characteristics can be still deeded as a significant evidence of group classification in the classification of fish.