Coral reefs in the Indo-Pacific are disappearing twice as fast as tropical rainforests, say researchers. They have completed the first comprehensive survey of coral reefs in this region, which is home to 75% of the world's reefs.

John Bruno and Elizabeth Selig of the University of North Carolina at Chapel Hill in the US compiled data from 6000 studies that between them tracked the fate of 2600 reefs in the Indo-Pacific between 1968 and 2004. They used the extent to which reefs were covered by live coral as an indication of their health.

"The corals themselves build their limestone foundation, so if the surface of the reef is not covered with live tissue that is continually secreting it, the reef can erode fairly quickly," explains Selig.

She and Bruno found that coral cover declined by 1% per year on average between 1968 and 2004. For comparison, tropical rainforests declined by 0.4% per year between 1990 and 1997.

In the early 1980s about 40% of reefs were covered with live coral, but that number had halved by 2003. Today only 2% of Indo-Pacific reefs have the same amount of live coral as they did in the 1980s.

The researchers found little difference between protected and unprotected reefs. "Well-managed reefs are definitely doing better in terms of fish population but not in terms of coral cover," Selig told New Scientist.

This uniformity has led Selig and Bruno to conclude that warming seas as a result of climate change are likely to be driving the rapid decline. Warmer oceans cause coral bleaching because higher temperatures kill their symbiotic algae. They also help diseases spread across reefs.

Selig and Bruno say local policies – for instance to limit harmful fishing methods and reduce continental run-off – can do much to help maintain the corals in the short-term, but long-term conservation will require an international effort to tackle global warming.

Baker believes more research is needed to explore whether anything can be done to boost corals' natural ability to adapt to change. “This might include attempts to inoculate the largest and oldest colonies on reefs with heat-tolerant symbiotic algae that might help them survive bleaching events,” he says.

Adapted from Source

Corals point into current flow. Swarms of anthias shelter near coral outcroppings and feed in the passing current. This photo was taken in a different coral reef area, near Fiji. (Credit: Copyright WWF - Canon/ Cat Holloway)

Reef fish and other marine species can breathe easier with the introduction of a fishing ban around Apo Reef, the largest coral reef in the Philippines and the second largest contiguous reef in the world after the Great Barrier Reef.

Under the ban, all extractive activities, such as fishing, and coral collection and harvesting, will be completely forbidden.

“This ‘no-take’ zone will allow the reef and its residents ample time to recover from years of fishing,” stressed John Manul of WWF-Philippines.

The 27,469-hectare Apo Reef off the coast of Mindoro Island is surrounded by mangrove forest, which serves as a source of food, nursery and spawning ground of several coastal fish and marine species, including sharks, manta rays, sperm whales and several sea turtles.

In 1996, the reef was declared a national park, but enforcement proved lax and illegal fishing methods persisted. The park was once one of the world’s premier diving destinations, but years of fishing — including by unsustainable fishing practices such as using dynamite and cyanide — took its toll.

“You would hear 25 to 30 dynamite blasts daily,” said Robert Duquil, a former protected area assistant superintendent. “The international diving community lost interest in the area and destructive activities prevailed.”

Adding to the reef’s troubles, the El Niño phenomenon in 1998 raised ocean temperatures, prompting a massive bleaching episode and the death of countless corals, and an explosion of coral-eating crown-of-thorns starfish.

“Unfortunately, Apo is plagued by millions of these starfish, probably due to a lack of natural predators like the giant triton, napoleon wrasse and harlequin shrimp,” said Gregg Yan of WWF-Philippines. “We hope that the ban will ensure protection of these predators and the many other reef species.”

WWF has been working towards sustainable coastal practices for the Apo Reef Natural Park since 2003. The marine park will be opened for tourists to help generate funds for its protection, as well as provide an alternative livelihood for hundreds of fishermen in the area.

Adapted from Source