The distant humming of luxury boats can be heard whizzing around Queensland's picture-postcard Whitsunday Islands.
But in a quiet spot near Hook Island, a tiny microphone is lowered into the sparkling turquoise water and the sounds emitted seem other-worldly.
Long guttural groans are broken by high-pitched whistles, almost like a bow being drawn along a violin's strings.
The giants of the sea are giving up their secrets to citizen scientists like master reef guide Kellie Leonard.
"The range of noises they make is fascinating … it really makes me want to know and understand what they're saying to each other and what it all means," Ms Leonard says.
"It's magic."
Tourism operators, reef guides, and visitors to the Whitsundays are all in on the act.
They're sharing their observations and recordings of humpback whales with a long-term monitoring program run by the University of Queensland's Cetacean Ecology Group led by Professor Michael Noad.
Under his supervision, PhD candidate Genevieve Williams trains almost 40 volunteers on board a boat as they head out to Hook and Dumbell Islands in search of the giant grey nomads.
"We find a calm spot where there are not too many boats racing around … and then as soon as you drop in the hydrophone you can tell whether there are any whales around or not," Ms Leonard says.
Whale acoustics
Detecting humpback whale songs is simple, but understanding their acoustics is far more complex.
Ms Williams has studied cetaceans for 15 years and her PhD thesis specialises in the social learning of humpback whales.
She says only male humpbacks sing, while females make social sounds.
"It's probably social sounds people are more familiar with," she says.
"The song is very structured, and it has a set hierarchy in which sounds are sung in a set order.
"They've got such a large repertoire of sounds."
Research also shows that within a population, the males' distinct patterns change every year and they are capable of learning songs from other regions.
Marine biologist Olivia Brodhurst, who is the director of consultancy group Whitsunday Environmental, says until now the monitoring program has not collected much data from the region.
"People will be able to put their hydrophones in the water, listen to the whales live and upload those once they get back to shore," she says.
Critical nursery
The Whitsundays are made up of 74 islands off the central Queensland coast and the sheltered waters provide a critical nursery for the whale species.
It's where females birth their calves, males in tow, during the great migration up and down Australia's east coast each year.
In 2022, humpback whales were taken off Australia's threatened species list after a major recovery in numbers since the 1980s.
Data from the Great Barrier Reef Marine Park Authority (GRMPA) shows whale populations are increasing by 10 per cent annually, and in 2023 it's estimated 40,000 whales will travel through marine park waters from north of Bundaberg to Cape York.
Now, there's a push to list the Whitsundays as a Whale Heritage Site, of which there are only seven in the world including Hervey Bay in Queensland.
It's an initiative created by the World Cetacean Alliance to formally recognise destinations that demonstrate sustainable practices and protect marine habitats.
Ms Broadhurst says if successful, it will make the region the first Whale Heritage Site within a World Heritage area.
"It would signify that the Whitsundays has met those global standards," she says.
"It's already a very highly managed marine park, there are already established citizen science programs, so what we're doing locally to add to those is trying to make sure that everyone in the community is more engaged.
"If you love it, you'll protect it."