Sri Lanka is situated south of the Indian sub-continent between 5° and 10° north of the equator. The island has a total land area of 65,000 km2 and a coastline of about 1, 585 km of which 300 km are beaches and sand dunes (GSL, 1985, Lowry and Wickremaratne, 1989, Olsen et al., 1992). The country's land area is about 65,610 sq km and is inhabited by approximately 18 million people. The maritime area of 230,000 sq km belonging to Sri Lanka is about three times larger than the land area. The continental shelf of the country as an area of about 31,000 sq km and the width ranges from 9 to 45 km with an average depth of 66 m (Cooray, 1967).

There are fringing and offshore reefs of varying conditions around the country. These have been categorized into three main habitat types. They are the true coral habitats consisting of live coral as well as calcareous substances, sandstone and rocky habitats (Rajasuriya & De Silva, 1988; De Silva & Rajasuriya, 1989; Rajasuriya, De Silva & Ohman, 1995). According to Swan (1983) about 2% of the coastline contains nearshore fringing reefs. The growth of coral reefs around Sri Lanka is influenced mainly by the monsoons which has a major impact on the level of turbidity and fresh water input into the coastal waters. As a result extensive coral reef habitats are limited to areas with lower levels of sedimentation with semi-dry climates found in the north-western and eastern coastal areas. Coral reef development in the southwestern sector of the coastline is poor due to heavy rainfall during the monsoon and the resulting impact from sedimentation and turbidity. Fringing coral reefs also occur around some of the islands around the Jaffna Peninsula.

Sandstone and rocky habitats are extensive and widespread. They are found from near-shore areas to offshore areas to depths more than 50 m. Although living corals colonize them to varying levels, live coral cover on these habitats is generally below 10%.

The coastal region supports 32% of the country's total population on 24% of its land area. This region also contains 66% of the urban land, 67% of the country's industry, and 80% of its tourism infrastructure. The marine fisheries contribute about 65% of the animal protein consumed by the population. The coastal fisheries classified as within 40 km from the shore provide the majority of the marine fish production (Baldwin, 1991). Nearly all of Sri Lanka's reefs are located within 40 km from the coast and they contribute significantly to the marine fish production (Rajasuriya and White, 1995).