Wreck Rock Beach is a long way from anywhere, but for hundreds of endangered sea turtles – and veteran turtle monitors Nev and Bev McLachlan – the lonely stretch of southern Great Barrier Reef sand is home away from home. Fringing the dense coastal scrub of Deepwater National Park 100 kilometres north of Bundaberg, this remote spot is at the forefront of the fight to secure South Pacific sea turtles a future.
“We’ve been coming here every summer since 1977,” says Nev McLachlan, relaxing with wife Bev in their bush camp. That doesn’t mean they take it easy. Sleep and turtle patrol are not bedfellows. Every night – often all night – during their annual eight-week vigil, the Sunshine Coast couple bounce along 22 km of starlit beach on quad bikes, looking for the loggerhead and green turtles that arrive on night tides to lay their eggs.
The first sign is usually tyre-like flipper tracks between the shoreline and tussocked dunes. In the dark, the evening’s first loggerhead looks at first like another sand dune or beach rock, albeit one with a reptilian tail and massive, craggy parrot-like beak. Flippers jerking and breath hissing, she hollows out a sandy depression (called ‘body-pitting’), then digs a hole (‘egg-chambering’) to lay 100 or so leathery, ping pong ball-sized eggs.
With expert ease, Nev notes the numbered metal tag on a foreflipper, and measures the shell length: 99.1 cm, a little above average. Nesting time and place, species and other particulars are also recorded and sent on to a centralised database.
Despite their far-flung location, Nev and Bev don’t work in isolation. They’re part of a long-term grassroots movement recording turtle activity at more than a dozen beaches along the Queensland coast and offshore islands. “I love going out and seeing the turtles and tagging and monitoring them,” Bev says. “But I now get probably more enjoyment out of looking at the databases.”
Data from volunteers such as the McLachlans and the scientists they assist, patiently amassed over many years, has proved vital for discovery and conservation. It established the now-famous fact that turtles return to nest at or near their birthplace. Queensland-collected data also revealed the temperature-dependence of turtle gender (warmer nests make mostly females), and the surprisingly advanced age at which turtles start to reproduce – about 30 years for loggerheads, and up to 45 years for greens.
Behind all these discoveries is Dr Col Limpus, Australia’s pre-eminent turtle expert, who has dedicated his life to their study and protection. The nerve centre of his operations is Mon Repos Beach near Bundaberg, the biggest loggerhead rookery in the southern hemisphere. Mon Repos hosts half the South Pacific’s nesting loggerheads – and since 1968, the world’s longest continuous turtle research programme.
In that time, Limpus has overseen the transformation of a site threatened by property development, predation by feral animals and with an 86 per cent decline in the turtle population into a viable, fully protected habitat and ecotourist attraction. Between November and March the Mon Repos rangers escort visitors on night tours to watch turtles nesting or hatching. Sometimes it’s hands-on – eggs laid in error below the high-tide mark will see the hatchlings drown, so they’re dug up and relocated with tourist help.
The will – and ability – to better protect turtles has grown as more about them becomes known. When Nev and Bev first came to Wreck Rock there was no national park. Foxes ran rampant, eating most of the eggs. Offshore, pregnant turtles were drowning in trawl nets. But by 2004, 30 years of data from Nev and Bev proved the beach was a critical turtle habitat and directly contributed to the waters off Wreck Rock being incorporated into the Great Barrier Reef Marine Park.
Several reforms have improved the outlook for turtles, although serious concerns remain. Baiting has now cut fox predation by up to 95 per cent, but goanna predation is a big problem. An education campaign teaches people living near nesting beaches to ‘cut the glow to help turtles go’ – that is, reduce outside lighting, which spooks laying mothers and hinders hatchlings from using the natural glow of the horizon to determine the direction of the water. Turtle excluder devices (TEDs) on trawl nets, compulsory since 2000, have meant 99 per cent less turtle bycatch on Queensland prawn trawlers. Loggerheads, with their crustacean diet, were especially vulnerable.
“Immediately there was a 30 per cent increase in nesting turtles,” Nev says of the TEDs. “They were being saved from drowning in trawl nets between nestings. But it wasn’t increasing the amount of new turtles. That’s still the big worry now.”
A Numbers Game
Identifying first-time nesters is simple: after five decades of tagging everything with flippers and a shell, they’re the ones without tags. But where are they? “They’re not returning to the area,” says Limpus. “So the older ones that die off aren’t being replaced.” At current rates, by 2020 there may be no new breeding loggerheads to replace their elders (the years between nestings increase as a turtle ages, although when they stop breeding altogether is still unknown).
Bev fears this is a legacy of the 1970s and ’80s, when nest mortality was extreme. “If they take 30 years to breed, did we have so much predation back then that not enough got to the water?”
Many thousands more hatchlings survive Queensland’s beaches these days, so first-returns might pick up when these more abundant generations mature. But turtles spend decades at sea before their first nesting, and their troubles out there are increasing.
By 2009, genetic sampling had confirmed Queensland-tagged turtles venture as far as South America in their first 15 years – these are the virtually unknown ‘lost years’ between when they hatch and return, almost fully grown, to Australian coastal feeding grounds.
It was troubling news. Peru and Chile have the world’s second- and fifth-biggest fisheries, and the European Union fleet now fishes those waters, too. “With 10,000 boats, even incidental catches of one or two turtles each is a problem,” says Nev.
Limpus goes further: “A hundred thousand loggerhead turtles are caught every year as fishing bycatch. A lot survive, but with hooks down their throats.”
A Helping Hand
Another danger is floating plastic, which turtles apparently mistake for edible jellyfish. More than 50 per cent of turtles worldwide are thought to have ingested plastic, which can kill by blockage, or sicken with leached chemicals. Then there are the multiple water-quality issues that affect seagrass growth, and possibly increase tumours and infections.
In Townsville, the Reef HQ Great Barrier Reef Aquarium has responded with a turtle hospital, where sick or injured turtles are given a chance to recover. More than 200 have been treated since 2008, but just two are in care today – a far cry from 2011, when 35 starved green turtles crowded the hospital to capacity after Cyclone Yasi devastated seagrass beds. One patient is a healthy juvenile green, a former research subject being monitored for release, but the other has “done the trifecta,” says manager Stephen Menzies, with a missing flipper (the result of fishing line entanglement), a swallowed hook and a badly cracked shell from a shark or crocodile bite.
Often it’s a waiting game – weight-size ratio, appetite, gut function and wound-healing are tracked until a turtle is fit for release. “We bring the water up to about 28°C to get the metabolism going,” says Menzies. “We reduce salinity to assist with rehydration, often a problem with malnourished animals. All the turtles we euthanise or that die are given a post-mortem – we learn more from them than ones we release. Sometimes we don’t know what’s wrong with them, but they recover.”
Assessing turtle health is tricky, because there’s little comparative data to measure it against. Seeking answers, James Cook University opened its Turtle Health Research Facility in Townsville last year, a world first. “We get a lot of sick turtles, but we don’t yet have a clear description of what a healthy turtle is,” says the facility’s Karina Jones.
Opportunity knocked during field research on Heron Island, a key Great Barrier Reef rookery, when 41 green hatchlings made the normally fatal error of emerging in daylight. “They were being completely swarmed by seagulls,” says Karina. “It was pure carnage, but we scooped them up and now they live here with us.”
Now safely lodged in numbered tubs, the tiny turtles enjoy twice-weekly shell scrubs with toothbrushes. Over time, their biometric data will build an accurate profile of turtle health. In any event, they’ll be easier to keep safe than their wild cousins, riding the cross-Pacific currents towards thousands of fishing boats and plastic bags.
Limpus, as Australia’s ‘turtle ambassador’, is heading an international action programme for loggerheads, aimed at unifying the conservation efforts of nine countries, including Chile, Peru, Ecuador and Australia. Despite slow progress, he remains optimistic. “When I started, green turtles were at a very low level,” he says. “During my time the population of green turtles has tripled. So we can turn it around.”
Driven by the same ancient instinct that saw their ancestral mothers heave ashore to nest back in dinosaur days, turtles seem incapable of giving up. And so, thankfully, are those working tirelessly to ensure this precious, prehistoric cycle of life continues into the ages ahead.