Lovely yet high-maintenance, vulnerable reefs may not survive global warming, despite labor-intensive conservation efforts. More focus should be on creating and protecting marine refuges in areas that won't collapse when oceans warm, a new study suggests.

"We need to create more parks in low-vulnerability areas where corals are more likely to survive," says marine biologist Tim McClanahan of the Wildlife Conservation Society. "If you allow heavy fishing in those areas, you are degrading what might have been a refuge from climate problems."

Reporting in the April 10 Ecological Modelling, McClanahan and colleagues mapped areas where warming water in the Indian Ocean has most stressed corals.

More than half of marine parks protected under international guidelines in the Indian Ocean are located in regions the team deemed vulnerable to warm-water death. They are vulnerable to a variety of factors, including surface current, temperature, wind and exposure to ultraviolet radiation. And only two of 61 protected marine parks—one east of Madagascar and the other off the southern African coast—are in resilient areas. Unfortunately, McClanahan says, park management off Madagascar is weak.

Climate change has already caused coral death around the globe. Warm waters bleach the corals when the heat-stressed, colorful inner symbionts dash off, leaving the corals to starve. Yet studies have shown that some corals bleach easier than others, and that some regions warm faster, for longer periods.

Biodiversity and socioeconomics are considered when no-fish zones are chosen, comments Andrew Baker of the University of Miami in Florida. Nonetheless, policymakers must start to also consider global warming, he says. "We need to prioritize efforts to protect those reefs that are more likely to survive the worst effects of climate change."

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