Body weight (kg) and body length (BL) measures (cm) of 30 wild-caught dugongs of both sexes; BL was measured in a straight line from snout to fluke notch while the dugong was restrained at the water surface (in-water) and on deck (out-of water). Curved BL was also measured out-of water to clarify error of the routine in-water BL measure. In all cases, the mean of three measures is reported. Error inherent in the in-water BL measure is reported as a percentage of the more precise out-of-water measure.