Corals under siege - destruction of coral reefs

Threatened by pollution, overfishing and global warming, coral reefs -- a lifeline for millions of people -- are dying off at an alarming rate

The vibrantly coloured rainforests of the sea received a disturbing bill of health during a recent gathering of marine biologists in Bali: in the past few decades, more than one quarter of the world's coral reefs have been destroyed by human activity. At the present rate, at least 57 percent will be lost within our lifetime.

This destruction threatens not only coral reefs, but also the lives of some 500 million or so people in southeast and southern Asia, eastern Africa and the Caribbean. For many of these coastal communities, corals are the largest source of protein: a healthy reef can provide more than 15 tonnes of fish and seafood per square kilometre each year, enough food for 2,500 people. And often they are the only source of income, employment and foreign exchange.

Coastal communities depend on their reefs to attract tourists, develop the capacity for commercial fishing, and protect shorelines from erosion and storm damage. In the British Virgin Islands, for example, 45 percent of revenue comes from tourism, which provides more than half of the territory's employment. A loss of reefs would probably cause the water to cloud with algae and the beaches to erode under the pressure of waves, leading to an estimated $130 million loss in income