Great Barrier Reef hit by worst coral die-off on record: scientists

Sydney

SCIENTISTS surveying the Great Barrier Reef said on Tuesday that it had suffered the worst coral die-off ever recorded after being bathed this year in warm waters that bleached and then weakened the coral.

About two-thirds of the shallow-water coral on the reef's previously pristine, 692km northern stretch are dead, the scientists said. Only a cyclone that lowered water temperatures by up to three degrees Celsius in the south saved the lower reaches of the 2,253km reef from damage, they added.