3.3. Foraging gain at different water depth
As for the fish catched at different water depth, the mean fish catch rate was 0.28 fish per minute in shallow waters, which is significantly higher than the value of 0.13 fish per minute in deep waters (Fig. 5A). However, as the prey in shallow waters was smaller (data not shown), the mean biomass of the fish captured was slightly greater in deep waters (Fig. 5B).