139736eo.pdf (20MB) - Japan Oceanographic Data Center

RESEARCH NEEDS FOR THE CORAL REEF ECOSYSTEMSOF THE CENTRAL INDIAN OCEANM.W.R.N. DE SILVANational Aquatic Research AgencyCrow Island, Colombo 15Sri LankaABSTRACTCoral reefs are unique tropical ecosystems that are important to the fisheries and touristindustries and are regarded as breeding and nursery grounds of many marine organisms. In addition,they act as barriers which prevent sea erosion. Unfortunately, in the Central Indian Ocean coral reefshave received neither the necessary attention nor respect. At present coral reefs in the Central IndianOcean are over-exploited, damaged and subjected to destruction that raises grave doubts about theirability to survive in the future.Most available information on the coral reefs of the Central Indian Ocean pertains to thetaxonomy and biogeography of the reef biota. Information about the structure of reef communities andtheir physiographic zonations is limited to only a few reefs.Major causes of coral reef degradation in the region are coral mining, use of explosives forfishing, natural sedimentation, tourist pressure and the removal of coral, reef fish and other reeforganisms for export or sale as souvenirs. ‘Crown of Thorns’ starfish (Acanthaster planci) infestationshave caused the destruction of some reef areas. Only a few countries in the Indian Ocean region haveattempted to control the degradation of their coral reefs by the establishment of coral reef parks orreserves.There is a need in the Central Indian Ocean and the adjacent regions for further surveying andmapping of coral reef areas as well as estimated economic productivity and potential, including theMaximum Substainable Yield (MSY) of exploitable coral reef resources. The causes and the rates ofdegradation of coral reefs must be determined and a concerted effort made to manage and conservecoral reefs in the area. Development of a central pool of Indian Ocean coral reef research andmanagement expertise in collaboration with other relevant marine disciplines could provide the nucleusfor much needed co-operative and comparative coral reef research in the region. Coral reef researchdata should be collected and disseminated; this can provide a regional basis for concerted efforts formanaging and conserving coral reefs.INTRODUCTIONFor many South Asian coastal countries, coral reefs traditionally have provided food, buildingmaterials, pearls and shells for jewelery, as well as sheltered harbours for boats. In addition they actas buffers which prevent sea erosion. The potential of several coral reef organisms as producers ofmedicinally important compounds has received the close attention of scientists in recent years (e.g.Angeles, 1981).For generations these reefs were able to provide for the needs of the local communities thatwere dependent on them. But today the coral reef resources are being exploited increasingly for exportto cities and other countries. Because of these increased pressures, reefs have been destroyed or badlydegraded in many areas. It is evident that immediate steps are required to stem the degradation of coralreefs for the benefit of present and future generations.The state of equilibrium of a coral reef ecosystem hinges around the delicately balancedinteractions within and between biotic and abiotic components. Critical disturbance, even to a singlevital parameter, can cause an imbalance leading to the destruction of the entire community.JOHANNES (1973, commenting on the importance of corals to the reef ecosystem, stated that “So153