The feature of morphological traits and their effects on body weight in the red crab (Charybdis feriata)

The red crab (Charybdis feriata) is one of most important fishery resources in China. In the present study, we first measured 17 morphological traits and body weight of C. feriata, characterized these 18 traits, and then estimated the effects of morphological traits on body weight by statistical methods including correlation coefficients, determination coefficients, path coefficients, and regression equation. All correlation coefficients between 17 morphological traits and body weight reached an extremely significant level (P<0.01). Determination and path coefficients analysis revealed the real correlation relationship between the independent variables and the dependent variable. Significant path coefficients were found between three morphological traits (stemum width, X₈; meropodite length of pereopod 3, X₁₆; meropodite length of pereopod 4, X₁₇) and body weight that suggested these three traits were the key traits directly influence body weight. Multiple correlation index (R₂₎ between above three morphological traits and body weight was of 0.977, which indicated that the main independent variables influencing body weight has been found. Finally a best-fit linear regression equation was established as Y = 13.078 X₈ + 7.048 X₁₆ - 4.902 X₁₇ - 576.635, which provided an ideal model for better understanding the feature of morphological traits and body weight of C. feriata.