Morphological Variation Among Four Populations of Charybdis bimaculata in the East China Sea and the Yellow Sea

Morphological variation among four geographic populations of Charybdis bimaculata in Jiaonan,Rizhao,Lvsi and Zhoushan were studied using one way- ANOVA analysis,principal component analysis,cluster analysis and discriminant analysis. One way- ANOVA analysis revealed the difference between Charybdis bimaculata from different geographical populations. The results of the cluster analysis showed that Euclidean distance between Jiaonan population and Zhoushan population was the largest among Charybdis bimaculata populations while Rizhao population and Jiaonan population was the smallest; cluster analysis indicated that there were morphological differences between the East China Sea population and the Yellow Sea population. The principal component analysis resulted in four principal components,the contributory ratios of the four principal components were 23. 685%,16. 475%,13. 662% and 10. 245%,respectively,and the cumulative contributory ratio was 71. 657%. Scatter diagram of the principal component indicated that the result of principal component analysis was almost the same with the cluster analysis. The discriminant analysis revealed that the discriminant accuracy of Jiaonan,Rizhao,Lvsi and Zhoushan population were 73. 7%, 78. 6%,36. 7% and 56. 7%,respectively; and the average discriminant accuracy was 61. 4%. The contributory ratios of two canonical discriminant functions established by discriminant analysis were 52. 7% and 35. 4%,respectively, and the cumulative contributory ratio was 88. 1%. The conclusion of the cluster analysis and the principal component analysis was supported by the result of scatter plots of canonicaldiscriminant functions. This research showed that there were morphological differences between Charybdis bimaculata populations in the East China Sea and the Y ellow Sea.