An unprecedented voyage is underway to find ways to protect the Great Barrier Reef.
Two summers of high water temperature have proven toxic for the reef, causing mass coral bleaching.
A group called Great Barrier Reef Legacy has gathered teams of researchers and reef experts from Australia and around the world, and are conducting the biggest underwater mapping and sampling expedition since the bleaching occurred.
They are also searching for so-called "super corals" that survived the bleaching.
The director of GBR Legacy and veteran tour operator John Rumney said the time had come to do something about the death of coral across large parts of the reef.
"I've been out here for 40 years and observed the changes in the reef," he said.
"When I first got here it was absolutely mind-blowingly beautiful and diverse, and over time we've seen it decline.
"We really need to start taking care of this, we're beyond the point of it taking care of itself."
ABC News has been told of how some reef tour operators are reluctant to talk to tourists about coral bleaching, in case it damages business.
But Mr Rumney said ignoring the issue was the wrong approach.
"[Human] impacts are really that great that we need to start having some stewardship in the reef," he said.
"Those of us that have seen it in the past are all sort of in a semi state of depression. It's like one of your children being really ill.
"It's quite emotional but at the same time we need the science to work out the solutions.
"This coral bleaching is this canary in the coal mine, it's a warning of what is yet to come. So it's no time to bury your head in the sand and pretend it is business usual."
The GBR Legacy research trip is funded by a major tour operator and other donors, including the environmentalist rock band Midnight Oil.