3.3.2. Feces production rate
The FPR of the small-sized group was significantly lower than that of the medium and large-sized groups (P b 0.05). However, no significant difference in FPR was observed between the medium and large-sized groups (P N 0.05). The mean FPR values were 4.0 ± 0.8 mg g−1 h−1, 4.9 ± 0.4 mg g−1 h−1, and 4.8 ± 0.4 mg g−1 h−1 for the small, medium, and large-sized sea cucumbers respectively (Fig. 6A). The nocturnal FPR was significantly higher than the diurnal FPR within each size class (P b 0.05; Fig. 6B).