23 February 2011 Last updated at 09:37 ET

Coral reefs heading for fishing and climate crisis

By Richard Black
Environment correspondent, BBC News

Healthy coral reefs provide a living for about 275 million people, with many more dependent on them

Three-quarters of the world's coral reefs are at risk due to overfishing, pollution, climate change and other factors, says a major new assessment.

Reefs at Risk Revisited collates the work of hundreds of scientists and took three years to compile.

The biggest threat is exploitative fishing, the researchers say, though most reefs will be feeling the impact of climate change within 20 years.

But, they say, there are measures that can be taken to protect at least some.

“If we don't learn from these successes then I think that in 50 years' time, most reefs will be goneâ€