Relations between morphological traits and body weight of shortbelly eel, Dysomma anguillare (Actinopterygii: Anguilliformes: Synaphobranchidae), from coastal waters of Zhoushan, East China Sea, determined by multivariate analyses

The shortbelly eel, Dysomma anguillare Barnard, 1923, is an essential component in the food chain of the marine ecosystem and plays an important role in nearshore fisheries and biodiversity in the East China Sea. In order to provide theoretical support for fishery resource assessment and sustainable utilization of D. anguillare, an important bycatch in the offshore area of China, the relations between morphological traits and body weight were investigated based on the measurement of 28 metric traits for the first time. The correlation analysis showed that 25 morphological traits were significantly (P < 0.05) correlated with the logarithm of body weight (lgX0), in which the correlation coefficient of the total length (X1) was the largest with the extremely high significance (P < 0.01). The optimum multiple regression equation of morphological traits was constructed after deleting redundant independent variables: lgX0 = 0.367 + 0.003X1 + 0.010X7 – 0.010X8 + 0.011X10 + 0.042X14 + 0.006X15 + 0.024X19 – 0.004X23. The total length (X1) had the highest positive direct relation with lgX0 (0.699), which was in accordance with the results of determinate coefficient analysis, while the indirect effect of body height (X7) through lower jaw length (X19) to lgX0 was the greatest. The gray correlation analysis indicated that body length (X2) and distance from snout to dorsal fin origin (X22) were the most closely related to body weight. The comprehensive comparison showed that X1, X2, and X22 should be used as the ideal morphometric traits for measuring the body weight of D. anguillare, and the conclusions obtained from this study will provide valuable references for fishery resource management of this commercial fish species.