Marine and Wildlife:
Beneath the sea at Mu Ko Similan National Park lies a complex ecosystem commonly called the rainforest of the sea: the coral reef. The major residents of the reef are coral and the closely related sea anemones; of the Phylum Cnidaria, Class Anthozoa, which contains all radially symmetrical invertebrate animals. Corals and sea anemones exist as individual polyps living in either solitary or mostly colonial forms. The polyps of hard corals construct communal limestone homes which are built up into a multitude of shapes and sizes eventually giving rise to a coral reef. Soft corals have soft bodies made of large numbers of identical polyps connected by fleshy tissue (Zooxanthallae). These soft corals contain small algae within their tissues which are able to convert the sun's energy into food. This cooperative relationship is known as symbiosis and also exists in hard corals, clams and other marine organisms. There are several factors that support good environment for the reef i.e. temperature, salinity, light, wave and tide, sedimentation and nutrient. Therefore, healthy coral reef can be found easily in the Andaman Sea comparing to the Gulf of Thailand. In Andaman Sea, coral reefs are able to classified as deep water and medium water. For the deep water coral reef grow down to 30 m. Of course, in this case water allows enough light for the algae. This reef type is mostly found in Similan and Surin islands. For the rest area, medium water coral reef grow between 8-15 m beneath the surface.