Protection zones not helping reefs, study finds

LONDON (Reuters) - Conservation zones in the Indian Ocean set up to protect fish stocks are not preventing coral reefs from collapsing due to warmer temperatures or helping to speed their recovery, researchers reported on Wednesday.

The reason is many of these non-fishing areas are located in warmer waters where coral reefs have a harder time surviving when temperatures rise suddenly, said Newcastle University marine biologist Nick Graham, who led the study.

The survey of 66 sites in 7 countries is the largest study of its kind and underscores the need for urgent action to save the important marine ecosystem, the researchers said.

The findings also show fishing limits that keep boats out and people out of fragile areas do not protect coral the way many scientists had thought, the researchers said.

"The Indian Ocean hosts some of the most diverse reefs in the world," Graham said in a telephone interview. "Current marine protected areas don't show any potential for faster recovery than non-protected areas."

Coral reefs, delicate undersea structures resembling rocky gardens made by animals called coral polyps, are important nurseries and shelters for fish and other sea life.

They are also considered valuable protection for coastlines from high seas, a critical source of food, important for tourism and a potential storehouse of medicines for cancer and other diseases.

But overfishing, climate change and human development are threatening reefs worldwide, including in the Indian Ocean where warmer water temperatures due to the El Nino weather system in 1998 devastated the coral population, researchers said.

"The West Indian ocean lost about half of its coral and some areas lost up to 90 percent," Graham said.

The researchers, who reported their findings in the journal PLoS One, looked at the coral population over a 10-year period beginning in 1994 to compare the before and after effects of the 1998 destruction.

They found that nine protected areas varying in size from 1 square kilometer to 14 square kilometers in the Seychelles and off the coasts of Kenya and Northern Tanzania were boosting fish stocks but not doing much for the coral.

Instead, coral was rebounding much faster in areas with cooler waters in Southern Tanzania, Reunion Island and Mauritius -- all areas with very few of the protected zones set up in the 1960s and 1970s.

The findings do not suggest existing protected areas should be scrapped but rather point to a need to focus conservation efforts on faster-recovering areas and manage the system as a whole, Graham said.

"We need to focus on areas that are recovering faster or escaping the impacts of climate change," he said. "This is where your brood stocks of coral areas are that will help seed other areas."

(Reporting by Michael Kahn, Editing by Giles Elgood)