An ocean survival expert says warm water temperature likely helped a couple survive three days drifting through shark-infested waters in central Queensland.
The man and woman were paddleboarding at North West Island on Saturday before they drifted 55 nautical miles to Yellow Patch near Curtis island.
A fisherman rescued them without their boards on Monday night when they were barely able to keep their heads above the surface while treading water.
Professor Mike Tipton, an ocean survival expert, said the tropical, warmer waters in central Queensland would have prevented the couple from developing hypothermia quickly.
"Which is why I suspect at the end of it, these individuals survived for three days," he said.
Tips to stay alive
Professor Tipton is a researcher at England's University of Portsmouth's Extreme Environment Laboratory, which studies how the human body survives in difficult environments.
He has also consulted the UK's Royal Air Force in survival medicine.
Professor Tipton said to survive at sea, the most critical requirement was air, followed by a warm enough body temperature, access to freshwater, and then food.
"The most important thing that people can do when they're going down to do activities around the water is wear a life jacket," he said.
"It means you can keep your airway — which is that number one survival priority — clear of the water with very little effort."
He said if swept out to sea without a life jacket, it was important to relax and float.
Professor Tipton said most people could keep between 3 to 5 per cent of their body above water while floating, which could mean keeping their nose or mouth above the surface to breathe.
He said for people lost at sea, the desire to drink saltwater increased with a prolonged lack of access to freshwater.
"Whatever you do, don't drink saltwater, even if you really are thirsty and craving saltwater, which is the situation people get to," Professor Tipton said.
Couple 'lucky' to be found
Senior Constable Troy Welsh from Yeppoon Water Police said it was still not known how the pair came to drift westward from North West Island to Yellow Patch .
"They've either got caught in a rip or a current, and they've been dragged out to sea," he said.
"They were floating around in the ocean until they were very lucky and picked up by the gentleman at Yellow Patch."
Senior Constable Welsh said the couple's survival was incredible.
"I can't recall people travelling that distance and surviving," he said.
"It's just an incredible will of survival and will to live."
A psychological challenge
Professor Tipton said people could survive between 40 to 60 days without food, and maintaining a positive attitude in a difficult situation could be life-saving.
"Obviously that positive mental attitude is helped by the fact that somebody will know you're missing, so that helps a lot," he said.
Professor Tipton said that outlook needed to continue after the rescue, when a person's condition could deteriorate quickly.
"We think that's the withdrawal of that positive mental attitude as people relax at the point of being rescued," he said.
"That can be made worse by the rescuer saying things like, 'Relax, you're safe, we've got you'.
"Instead, what the rescuers need to do is encourage people to keep that positive mental attitude and to keep fighting for their survival."
Notify others of your plans
Senior Constable Welsh said it was vital for those heading out on ocean adventures to let somebody know their movements.
"Tell someone else where you're going and what time you'll be home because if we were aware of it we could have started looking for them a lot earlier," he said.
Adam Balkin, owner of Curtis Island Ferry, which drops campers at North West Island, said the location was a "wilderness experience".
"You're 100 per cent off-grid and you're an hour away from a helicopter rescue and three hours away for a rescue boat," he said.
"[There is] very limited phone service. If you have Telstra, you've got to wait for the tide to go out, go down one end of the island and climb a tree to get very limited service.
"There is obviously radio service out there and [Queensland] National Parks recommends to take a satellite phone or radio communications when you go out there."
