Coral reefs are not only eye-catching − rich in marine biota but are mostly calcium carbonate (caco3). In general, more than 50 per cent of calcium carbonates of coral reefs are contributed by algae. It consists of corals, their skeletons and reef as fundamental ingredients.

Coral reefs are highly productive areas being the home of various types of fish and other marine fauna and are rich in biodiversity. In terms of economic and ecologic value, these are very important areas. Reef building corals necessitate warm and lucid water to breed and are found in shallow waters close to water's edge. As a result, these are vulnerable to toxic elements, contaminants and silt.
Coral reefs protect our coasts from waves, storms, and floods. It forms a barricade to protect the shoreline from waves and storms. It helps to avert loss of life, property damage, and erosion., all-inclusive there is some 600,000 km, 10 % of which is totally tainted and other 30% would degrade within the next twenty years.
The increase of human population is the foremost root of this dreadful conditions of the coral reefs. Constructions on coral reef islands or alongside the coastal areas have led to unwarranted domestic farming and industrial contamination. The toxic elements being discharged in coastal waters find their way into reef areas killing coral building polyps. Toxic elements put off larval development and destroy grown-up flora and fauna which are essential component of reef population. A mile of reef at Eilat in the Red Sea (Israel) was scratched by unremitting oil and fertilizer pollution.
Fishing with toxin is extremely disparaging to reef systems. In addition, herbicides and pesticides from agricultural run-off can have undesirable impacts on coral reef. Mess, nutrients and fertilizers lead to eutrophication and may be the foundation of the death of reef organisms. Land usage and deforestation leads to too much silt being carried into the coastal waters. It also reduces the dissemination of light thus leading to ultimate death of coral polyps. These are widespread practices in coastal areas of Bangladesh.
Overexploitation of coral resources is another root of degradation in our country. Mining of coral reefs for lime in Sri Lanka has led to wearing away the seashore. Silt washed into the ocean area killing reef life causing permanent destruction of corals.
In Bangladesh, only a petite region in the St. Martins Island consists of coral reefs. Even that is defenseless. The marine sciences institute, Chittagong − had isolated 13 genera of corals in the area also several species of fish and algae. The island supports 85 species of birds, 12 species of mammals, more than 20 species of reptiles and 4 species of amphibians.
The destruction of this minute coral ecosystem − the only one in Bangladesh, is due to assorted on-site and off-site anthropogenic and natural hazards.
On-site and off-site pollution from households, manufacturing and ship sources and from fishing trawlers plying on the waters are focal threats to the coral reef ecology. Agricultural run-offs from plain land and processing of fish for drying also contribute to contamination of the reef water. Compilation of corals and shells for money-making purposes and overfishing in ocean area are also causes of dreadful conditions. Plying of boats and trawlers in the bay area − for the purpose of fishing or transporting people, goods, and anchoring those boats are also detrimental to the reefs.
In general, in our coral reefs area there is no command over tourists who visit the island and no regulations restricting their negative externality. Walking over the reefs, collecting of shells and breaking off corals − contribute to demolition of reefs. During the monsoon, rivers carry heavy loads of silt into sea, recurrent flash floods in the mainland carry sediments. Silt and sediment hinders coral escalation and are important causes of degradation of coral reefs in Himchari and the St. Martins Island.
Unless indigenous strategies are followed in protecting the reefs, we may soon annihilate this attractive land of biodiversity. The government has declared St. Martins island an ecologically endangered area. Even if the government encourages eco-tourism, only guided tours should be permissible in the St. Martin Island. Tourist should be informed about regulations and protective measures should be taken for the coral reef island. In fact, rules and regulations should be enforced.
Time has come for the inhabitants of the island to be aware about the effects of the destruction of the coral reef ecosystem. The unfavorable impact on the fisheries itself may guide the fishermen to make use of the fishing grounds more sensibly.
It is possible to prevent local pollution through educating the inhabitants and monitoring their activities.  We have to deal with off-site contamination through pollution control policies.  Apart from that, government has to come forward with home-grown agricultural and forest management strategies to thwart top soil erosion, which has turned into a danger to the endurance of coral reefs and environmental security.

The writer is environment analyst and Associate Member of Bangladesh Economic Association
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