As one of the major tourists’ destination, Mu Koh Chang has the variety of coral reefs underneath its islands’ seabed. Fringing reefs develop around most of the islands and coral communities are also found on off-shore pinnacles.
Mu Koh Chang’s total coral reef areas are approximately 16 square kilometers and over 130 scleractinian coral species have been reported with average live coral coverage around 40%. The dominant corals are Porites lutea, Pavona decussata, Echinopora lamellosa, Goniopora spp., Pavona spp., Symphyllia spp., Fungia spp. and Astreopora sp. The sponge, Xetospongia sp. is also abundant. Coral reef conditions of a group of small islands north of Koh Chang are fair with an abundance of Porites lutea and Symphyllia spp. Coral reef conditions of the Koh Mak group, the largest coral reef area, are poor.
The dominant corals are Porites lutea, Diploastrea heliopora, Goniopora spp. and Symphyllia spp. The sponge Xetospongia sp., soft coral Sinularia sp., giant clam Tridacna spp. are also common in the area. Coral reef conditions around Koh Kut groups are fair with an abundance of coral Porites lutea, Diploastrea heliopora, Symphyllia spp., and Faviidae, and giant clams Tridacna spp. Coral reef conditions around Koh Chang and small islands nearby, except the northern part, are poor.