EFFECT OF WATER VELOCITY THROUGH CAISSON JOINTS ON THE CORAL DISTRIBUTION ON BREAKWATERS

Abstract

 Enhancing coral growth is important given the current declining trend of coral reef ecosystems. We investigated coral distribution and flow structure around caisson joints and conducted the hydraulic model experiments to estimate the water flow velocity throuth the caisson joint varying with wave conditions, in light of the positive effect of water flow on corals. The coral (especially Acropora spp.) cover of caisson joints was higher than that of the center of caisson in Naha Port. The coral cover increased with increasing width of the caisson joint and become highest around ~1 m. The flow velocity also increased with increasing width of the caisson joint, indicating that water velocity through caisson joints enhanced ambient coral growth.