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There are various factors which post threat to the formation of coral reefs. They can be classified as Natural and Anthropogenic threats to coral reefs
A. Anthropogenic Threats to Coral Reefs
(i) Over fishing: Overexploitation of fishing happens due to the high demand leads to the imbalance of ecosystem of Coral Reefs. For example, Overfishing of herbivorous fish may result in the high level of thriving of algae in the reef.

(ii) Destructive Fishing Methods: Using cyanide and Dynamite while fishing make the ecosystem completely unsustainable. In Cyanide fishing, sodium Cyanide mixture is sprayed to stun the fish to catch them live for aquarium. It affects the other species as well as corals and its ecosystem. Blast or dynamite fishing use explosives to stun or kill the school of fish, thereby creating disaster to the underlying habitat including coral reefs. Even the dropping of anchors from the fishing vessel and leaving debris of fishing net can break the corals from the reef.

(iii) Unsustainable Tourism: Unregulated Tourism creates pressures over the reef ecosystem. The resorts and hotels discharge sewage or untreated water and also dumping of wastages over the ocean pollute clean and clear water. This restricts the coral growth and its existence in the ecosystem. Further, there will be lot of physical damage done to the coral reef by the swimmers and divers who are not regulated properly.

(iv) Coastal Development: The projects like building airports or other construction projects are identified on the land reclaimed from the sea. This poses the threat to the survival of coral reefs. Further building deep water channels or marinas disturbs or destroys the sensitive habitats like coral reefs.

(v) Pollution: An insensible and unaware activity of the human in disposing the wastages pollutes not only land and atmosphere and also water. It may evident in the fact that the wastages which are dumped on land may be transported by rivers to the sea. Again even the oil spill on the ocean water also creates havoc to the reef ecosystem. The spilled oil can only float on the surface of the water and can evaporate. But it causes damage to larvae of coals which float before they settle on hard surface. In this way, it becomes the major cause for the reduction of coral reproduction and also damaging other species.

(vi) Indirect Human Activities: We have already seen that mangroves and seagrasses are also the parts of coral reef ecosystem. When the human disturbances happen to these components, they have their impacts on corals also. For example, Mangroves, being a integral part of Reef Ecosystem, filter sediments and make the water clean and clear. It favours the corals to reproduce and grow. But the mangroves are exploited for wood and other benefits by human. Due to these kinds of human activities, the growth of corals are affected thereby the reefs.


The Climate Change is the major cause for the damage to Coral Reefs. The factors of Climate Change which have its impacts on Coral Reefs are:
• Rise in Temperature
• Rise of Sea Level
• Modifications in the trends of cyclone and storm
• Acidification of Sea Water