Climate and ocean scientists say the longest global coral bleaching on record, which is coming to an end, has left a trail of destruction, causing major damage to reefs in the Pacific.
The worst-affected reef system is on Jarvis Island in the central Pacific, where 98 percent of coral has died, and there are similarly high numbers for the parts of the Great Barrier reef and Kiritimati Island in Kiribati.
Global coral bleaching occurs when conditions in all three of the world's ocean basins that contain reefs become toxic to coral which are the foundations of life in tropical marine ecosystems.
The current event, caused by increased ocean temperatures, was announced in 2015.
The US' National Oceanic and Atmospheric Administration's coral reef watch co-ordinator Mark Eakin said the 2015 event was the longest and most widespread on record.
He said he was also expecting it to be the most damaging once the extent of the destruction was fully known.
"And a part of that was because since this was a multi-year event you had a number of areas that bleached more than once during this event and so that return of bleaching so quickly sometimes one year after the next has caused a lot of damage," he said.
Dr Eakin said they would be monitoring the temperature of the world oceans carefully over the coming months to confirm that the global coral bleaching event had indeed ended while warning that high temperatures could still persist in some areas.