Scientists say mass bleaching has killed more than a third of the coral in the northern and central parts of Australia's Great Barrier Reef, though corals to the south have escaped with little damage.

The ARC Centre of Excellence for Coral Reef Studies released the results of its survey of the 2,300-kilometer (1,430-mile) reef off Australia's east coast on Monday. The scientists found that about 35 percent of the coral in the northern and central sections of the reef are dead or dying. Some parts of the reef had lost more than half of the coral to bleaching.

Terry Hughes, director of the reef studies center at James Cook University in Australia's Queensland state, says the extent of the damage has serious implications.