Field observations and numerical analyses using a wave model,an ocean model and a particle tracking were performed to investigate relationships between distributions of corals,waves and sediment transports in Amitori Bay,Iriomote Island,Japan. At the mouth of the bay,high wave height and low sedimentation,tabular coral groups were dominant. In the inner part of the bay,where is calm and much sedimentation,tabular groups decreased and small coverage of massive and branching types were remained. In tabular coral group, Acropora digitifera, A. millepora and A. hyacinthus were dominant species. Acropora digitifera distributed low wave height and a few sediments. Acropora millepora could distribute as long as the wave is high even in case of much sediments.
