Sediment plume simulation from bottom-trawled fishery and deposition effects on rhodoliths and deep-water corals from Campos basin, Brazil

Abstract

Extensive rhodoliths and deep-water coral has been described along the continental shelf and slope of the Campos Basin, but such environments can be highly vulnerable to the bottom trawling fishing. This study applied the MOHID software to simulate the sediment resuspension during the bottom trawling operation and to evaluate possible impacts of sediment deposition onto rhodoliths and deep-water coral. The sediment transport model was validated by field measurements of a bottom trawling operation and presented good accuracy. The results indicated that sediment resuspension by a double-rig trawling induced a 0.13 mm sediment layer deposition onto the rhodoliths from the continental shelf which has potential deleterious effects considered that such thickness is higher than the threshold proposed by the literature. On the contrary, a sediment resuspension/deposition by a single-rig trawling has no impact in the deep-water corals from the continental slope based on the thin layer deposition that was lower than the proposed tolerance limits.