At each study site, three permanent belt transects of 50×1 m2 were placed perpendicularly to the shoreline in which all visible coral colonies (≥5 cm in diameter) were counted and identified to a species level, if possible, and their coverage was quantitatively estimated. Quadrats (1 m×1 m), subdivided into 100 squares of 100 cm2, were positioned along the transect. The quadrats were also photographed with an underwater camera for re-investigating the data. The reef surveys were undertaken in March 2004, 2006, 2008 and 2010.