The offshore island of St. Martin’s is the only area with corals in Bangladesh and is heavily influenced by monsoons and frequent cyclones. There are no true coral reefs around this island, only coral aggregations in shallow waters along with seagrass beds, soft coral habitats and rocky habitats. There is heavy sedimentation from the combined discharge of the Ganges, Brahmaputra and Meghna rivers, which contribute about 6% of the world’s total sediment input into the oceans.

The only coral communities in Bangladesh are found around St. Martin’s Island. A fringe of rocky substrate and coral communities extends about 200 m from the island, with a total reef area of less than 50 km². The area is influenced by freshwater influx, monsoons and frequent disturbances such as cyclones and storm surges, resulting in high sedimentation as well as mechanical damage. Pressure from human activities, mainly resource exploitation, tourism and coastal development, is high. A shallow reef area about 15 km west of St. Martin’s Island, locally known as Marphati bandth is not currently under any form of management, but is less damaged due to its inaccessibility to coral poachers.