The Sany Bay, covering an area of 120 km2 between 109.3333 and 109.5 E and 18.183 and 18.3 N, surrounded by the Sanya city. It is a typical tropical bay in China. Dongmao Island, Ximao Island and Luhuitou, located in the bay mouth, possess mostly coastal coral reefs. The Sanya River, located in the eastern part of the bay, has many kinds of tropical habitats including coral reefs, mangroves, rocky and sandy shores, mudflats, etc. The coral reefs and mangroves have special resource value and ecological benefits and are, therefore very important to the sustainable social and economical development in these tropical coastal areas. Coral reefs and mangrove areas have important relationships to the regulation and optimization of the tropical marine environments.