Great Barrier Reef: What's going on with Australia's biggest tourism attraction?
As Sir David Attenborough's Blue Planet II hits TV screens, Sarah Marshall visits the world's largest coral reef system.
There's something universally irritating about noisy eaters, but below the surface of the ocean, dining etiquette doesn't really apply.
Munching merrily on brittle stumps of branch coral, a shoal of rainbow-hued parrot fish is causing quite a commotion.
A black-tip reef shark wriggles to the silent safety of a shadowy jetty, white-spotted eagle rays flap their wings to pick up speed and giant clams appear to purse their thick blue lips in a concertina of disgust.
It's restaurant rush hour off the shores of Heron Island, a coral cay sprouting with dense pisonia forest and ringed by a brilliant white halo of sand, off the east coast of Australia at the southern end of the Great Barrier Reef.
Yet, lifting my head out of the water to gasp air, I'm met with silence and calm.
Teeming with wildlife and natural wonders, our oceans are a noisy place. And right now, they're crying out for help, a reality we're only just tuning into.
Marine conservation is a central theme of BBC One's highly-anticipated Blue Planet II series (starting Sunday, October 29), narrated by Sir David Attenborough, and the naturalist is urging us to protect an environment we know woefully little about.
Earlier this year, Australia's Great Barrier Reef was the subject of controversy when scientists warned that more than 90pc of the planet's largest living organism might have been destroyed. Having narrowly escaped being listed by UNESCO as a World Heritage Site in Danger, a recovery plan is now under way - both for the reef and its worldwide reputation.
Sir David has been to Heron Island several times and describes it as one of the most magical places on earth. After his last visit, the 300-person resort was at full capacity. "We call that the Attenborough effect," says general manager Sandy McFeeters.
Located 81km from Gladstone, Queensland, the island is reached by a two-and-a-half-hour boat journey or, as in my case, by a 20-minute seaplane ride, wading to shore in clear, warm water with luggage hoisted overhead.
There's no phone coverage, no disturbance and no locking system on doors. At sunset, a burning ember fizzles below the horizon, singing the sky with charcoal streaks, and nightfall invites a starlit 40-minute circumnavigation.
An important nesting site for loggerhead and green turtles, the peaceful island has a grim past as a turtle and mutton bird canning factory. Over the course of two summers, 128,000 cans of turtle soup were produced, but an alarming drop in numbers meant the business was no longer economically worthwhile.
A resort opened in 1932, although any ecotourism was crude, and gasp-inducing photos from the 1950s show holidaymakers riding on the back of carapaces.
Now the island, part of the Capricornia Cays National Park, is heavily protected. Of the 1,500 species of fish living on the Great Barrier Reef, 60pc can be found in the 21 dive sites at Heron island, says blond tousle-haired scuba and snorkel guide Rick.
Passing the wreck of HMAS Protector, one of Australia's first naval vessels which will be declared a preservation site in 2018, we snorkel to Heron Bommie, a heaving tower of coral not far from the shore. (None of Heron's sites are more than a ten-minute boat ride away.)
Two blacktip sharks (Rick's "pussy cats of the reef") relentlessly chase a whitetip around spiral-ridged brain coral, while a green turtle makes himself a comfortable bed on cushioned plates, blinking only a disgruntled eye as we free dive to observe him.
Most corals on the Barrier Reef are hard, meaning the underwater scenery is a swirl of camouflage hues, rather than the bold neon brights associated with soft corals.
"Besides, below five metres, you lose any colour," explains Rick.
Even during winter (August) when I visit, the water is a pleasant 21C and the visibility is excellent. Cooler temperatures partially explain why coral has survived much better here than in northern reaches of the reef. Anything above 30C causes the organisms to expel their zooxanthellae algae, leaving behind a frail white skeleton, a phenomenon known as coral bleaching.
Investigation into the effects of climate change is being carried out at the island's Research Centre, built in 1951 and partly funded by the University of Queensland.
"The scientific community is divided," explains Education Officer Lauren Bailey. "Some researchers say it's too late and others are confident the reef will survive - it might just look a little different."
Innovative projects in development at the centre include Professor Peter Harrison's plan to funnel spawning to affected reefs, and Professor Bernard Degnan's groundbreaking solution for controlling crown of thorns starfish (a potential threat to reefs) - by replicating a natural pheromone to lure them in.
"We have to redress all these negative messages," stresses Lauren. "We can't give up hope."
A similar outlook is shared by Peter Gash, manager of the eco resort on Lady Elliot Island, at the southern tip of the reef.
Mined for guano in the 1860s, the wind-whipped coral cay was left barren and desolate. Many years later, it opened as a resort and when Peter visited in 1979, a love affair began.
Since taking over the lease in 2005, he has installed solar panels, cut fuel burn by 90% and replanted much of the original casuarina forest, bringing back a cacophony of screeching bridled terns and white-capped noddies.
"Not everyone is happy about that," he tells me. "But we make sure there are earplugs in every room."
Although no spring chicken, Peter is a dynamo. On a guided tour of the resort's back room operations, I'm lost in a muddle of mathematics as he details engineering innovations with vigour. Swept away by his energy and enthusiasm, it's impossible not to smile.
And he's obviously making a success; bookings for Lady Elliot need to be made at least six months in advance.
Simple rooms curve around the fringes of the island, and drift snorkel sites have been clearly marked out. Like Heron, the underwater spectacles are outstanding, and all within easy reach.
One afternoon, I spend several hours wallowing in a shallow lagoon, only accessible at high tide. "Look out for Buddy, our resident turtle," shouts resort manager Andreas Supper, from the restaurant decking. "He likes having his back scratched."
Within 45 minutes, I've seen 14 turtles. Distracted by filling their stomachs, none are perplexed by my presence - although I don't receive any invitations for tummy tickling.
The best time to explore is at dawn, Peter tells me, so I nervously agree to a 6.30am snorkel. As we walk across the island in semi-darkness, gloomy pandanus trees appear to be lifting their sinewy roots to join us and flitting bats are in a rush to reach home.
Leaving the shadow of the beaming lighthouse behind us, we dive into another reality and Peter guides me on an underwater safari of his favourite sites. Polyps finishing their night's feed sway with the tide, sage loggerheads drift over ancient living columns and mantas glide elegantly with wind in their sails.
We're the only two-legged land mammals out of their depth; down here it's a real democracy.
As much as the sights are enticing, so too are the sounds.
An undulating whine wends into my headspace and I realise I'm listening to humpback whale song. Even though the migrating animals are probably a long distance away, their stirring voices are penetrating.
Yet, there's nothing melancholic or mournful about their cry. Instead, it's graceful and uplifting, striking a chord with hope.
Sarah travelled with Travelbag (travelbag.co.uk; +44 (0)207 001 5252), which offers a 9-day trip to the southern Great Barrier Reef, split between Brisban, Heron Island and Lady Elliot Island on a mixed board basis, for £2,999/€3,370pp.
The price includes flights from London Heathrow. Based on a January 1, 2018 departure. Book by November 30. For more information, visit australia.com and queensland.com.
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