It’s an ancient journey unchanged for millions of years. Every summer, endangered giant leatherback and smaller loggerhead turtles lumber onto the beaches of Maputaland, KwaZulu-Natal, to give life to a new generation.
There’s a mood of excitement and expectancy as we drive over the forested coastal dunes and onto the sandy beach near Rocktail Bay.
The sun is stretching its last lazy rays across the sand and the Indian Ocean is retreating slowly for low tide. Calm and balmy, there’s just a sliver of moon as the light fades to night.
“These conditions are just perfect for leatherbacks,” says guide Gugu Mathenjwa, as he drives the Land Rover slowly below the highwater mark. “Turtles don’t like a lot of light when they lay their eggs.”
Gugu has been monitoring marine turtles for over 20 years and is accompanied by turtle researcher Chris Boyes. Every night during turtle season, from October to March, the two men patrol a specific section of beach to monitor the ancient creatures and their activities. They tag and measure the turtles, and share the data with the local conservation authority, Ezemvelo KZN Wildlife, which has monitored turtles in Maputaland since 1963. Back then, just five leatherbacks nested on this 200km stretch of beach; now, at least 90 come to lay their eggs every year.
As we drive further, Gugu points out a wide drag mark between the water’s edge and the dunes. “That’s a turtle track,” he says, “but she’s already back in the sea”.
Then, further along the beach, the headlights bounce off a massive turtle clawing her way slowly up the sloping beach towards the dunes. She leaves the characteristic drag marks behind as she uses full throttle to make the difficult journey across soft sand, her flippers not nearly as agile as they are in the sea.
We slow down and watch from a distance, in awe of the moment and not wanting to intrude on her privacy. She’s a large and lovely leatherback – the biggest of all marine turtles and weighing up to 900kg – with the characteristic seven ribbed lines running down her navy-blue back.
The expectant turtle chooses her nesting spot carefully above the high water mark, and for the sand texture so the nest doesn’t collapse.
Then she starts scooping sand with her larger front flippers to create a body support for herself. Once settled, she starts digging a round drop-hole with her smaller back flippers. Sand flies as she goes about the slow-motion excavation, which can be up to a metre deep. When completed, she positions her body to gently drop up to 100 eggs into the hole. During the process, she seems oblivious to her surroundings, almost transfixed by the task at hand.
For every 100 eggs, 60 are large and fertilised and the other 40 are small and infertile – but we don’t know why that is. When the female turtle has finished laying, she carefully fills the hole with sand – again using her back flippers – then sprays sand around with her front flippers to disguise the nest site from jackals and honey badgers.
Now she starts her laborious journey back to the beach and into the waves. She must again gather resources and eat plenty of jelly fish to be able to lay another batch of eggs in about 10 days’ time.
Through the laying season she could lay up to 1 000 eggs, but probably only one or two of her hatchlings will survive to adulthood.
Two hours have passed watching the leatherback nest and return safely to the ocean. It will take another 70 days for her eggs to hatch and the surrounding sand temperature will determine if the offspring are male or female. Temperatures over 29.5°C produce females, below that males. Hatchlings burrow their way out of the sand together – again under cover of night – and the tiny turtles run the gauntlet through an army of ghost crabs all the way to the sea. Then there’s a whole new set of predators waiting to snack on them, and only when the hatchlings get 5-10km out to sea and enter the warm Agulhas Current can they breathe easily. Researchers believe their sprint to the sea imprints that specific beach on the young turtles, so full-grown females can return 15 to 30 years later to lay their eggs on the same beach.
“It’s just amazing,” muses Gugu as we drive back in quietness.
“I can only think the turtles remember the smell of the beach and that’s how they find it again.”
Researchers now believe this is precisely what happens, possibly supplemented by an innate GPS. Leatherbacks do trans-Atlantic and trans-Pacific crossings and one was clocked having travelled 19 000km in 10 months. Loggerheads also undertake massive migrations, with one tracked having completed a 10 000km trans-Pacific migration.
However, it’s precisely these long journeys that put leatherbacks at high risk. Long-line fishing kills many turtles – up to 40 000 every year. Turtles are also caught and killed in fishing nets and there is still a black-market trade in their eggs and meat in some parts of Latin America and the Far East. In other countries their nesting sites are crushed by vehicles or disturbed by overdevelopment. In South Africa, however, these ancient marine reptiles are well protected and conserved, on land and in their natural ocean habitat. Here they are free to fly through the water and dive to great depths. And every year when instinct and nature beckon them onto the Maputaland beaches, they heed nature’s rhythm. And humans can watch in awe.
l To see Maputaland’s turtles and stay at Rocktail Bay contact www.wilderness-safaris.com or call 011 807 1800. For general turtle information see www.seaturtles.org - Saturday Star