Australia’s iconic Great Barrier Reef suffered its biggest ever decline last year after a marine heatwave bleached vast swathes of hard coral, a new report has found.

Two of Australia’s Great Barrier Reef regions have faced the largest decrease in coral cover since records began nearly 40 years ago, a new report reveals. The Australian Institute of Marine Sciences states that coral cover on the reef has decreased by about 25% to 33% after several years of solid growth.