Effects of Different Cultivation Modes on Morphological Traits and Correlations Between Traits and Body Mass of Crayfish ()

In this study, juvenile crayfish hatched from the same population were cultured in different growing environments: pond (), paddy field (), and aquaculture barrel (), and fed for 60 days. Crayfishes were selected randomly, females and males, 50 tails each from six groups (D1-♀, D1-♂, D2-♀, D2-♂, D3-♀, D3-♂) to measure the following morphological traits: full length (), body length (), chelicerae length (), chelicerae weight (), cephalothorax length (), cephalothorax width (), cephalothorax height (), eye spacing (), caudal peduncle length (), and caudal peduncle weight (). We found that the coefficient of variation (CV) of was the largest in each culture mode, and males (28.58%~38.67%) were larger than females (37.76%~66.74%). The CV of of crayfish cultured in and was larger than that of . All traits except were positively correlated with body weight ( < 0.05). After pathway analysis, we found that , , , and were significantly correlated with the body weight of D1-♀; the equation was = -29.803 + 1.249 + 0.505 + 0.701 + 1.483 ( = 0.947). However, , , and were significantly correlated with the body weight of D1-♂; the equation was = -40.881 + 0.39 + 0.845 + 1.142 ( = 0.927). In D2-♀, , , , and were significantly correlated with body weight; the equation was = -12.248 + 0.088 + 1.098 + 0.275 + 0.904 ( = 0.977). and played a major role in the body weight of D2-♂ with the equation: = -24.871 + 1.177 + 0.902 ( = 0.973). and mainly contributed to the body weight of D3-♀ with the equation: = -22.476 + 0.432 + 3.153 ( = 0.976). and mainly contributed to the body weight of D3-♂ with the equation: = -34.434 + 0.363 + 0.669 ( = 0.918). Comparing the pathway analysis with the gray relation analysis, we could conclude that the traits most correlated with body weight in D1-♀ were and ; in D1-♂, ; in D2-♀, , , and ; in D2-♂, ; in D3-♀, ; and in D3-♂, and .