On a beach in Costa Rica, a majestic sea turtle drags herself onto the sands with one purpose: to sow the seeds of the next generation.
Every morning, the Costa Rican sunrise casts vibrant shades of purple, red and orange across the horizon. I am lying on the sand, waiting for the night's last turtle to finish laying so I can get some much needed sleep. I raise my head to check its progress; it's a black turtle (Chelonia mydas), or ‒ to my Spanish-speaking assistants ‒ ‘una negra’.
This particular female emerged from the waves at midnight, dragging herself forward inches at a time towards the vegetation at the top of the beach. Having found the perfect spot for a nest, out of reach of high tide and under the cover of a tree, she begins to ‘body pit.'
She throws the dry top layer of sand behind her with her front flippers and sweeps it like a windscreen wiper with her back flippers. Having reached the wet sand, she begins her egg chamber, alternately scooping sand with one rear flipper and flicking it away with the other. Satisfied that she is far enough into ‘chambering’, I feel confident scanning her. I wave the scanner over her front flippers, in search of a microchip, the same type that is in your cat or dog. Nothing. She is a new arrival for the season.
Over the past two years, I have spent two nesting seasons with the Leatherback Trust, first at Las Baulas National Marine Park near Playa Grande ‒ one of the jewels of Costa Rica’s national park system ‒ and this year at Playa Cabuyal, the very picture of a tropical paradise.
Five months of sleep deprivation, no electricity or internet, and a tarantula for a roommate can be pretty tiring. But the loss of a few modern luxuries is made up for by the beauty of Costa Rica’s people, along with the tranquility of spending your nights on a tropical beach under more stars than you can count.
The story of Playa Grande reflects that of many nesting beaches around the world. When only a few local families populated the region, egg poaching had minimal impact on the thousands of leatherback turtles that came to nest each year. However, the construction of a road in the 1950s gave more people access to the beach, and in the last 20 years close to 100% of eggs laid each season were being poached. The ensuing decline in the annual number of nesting females from over 1000 to just over 20 has left the eastern Pacific leatherback population a shell of its former self.
Turtle eggs and turtle meat have been a traditional delicacy all over the world, from Central America to Australasia to Africa. European ships used turtles as a long-lasting source of fresh meat. These same ships reported difficulties navigating through the Caribbean during the 15th and 16th centuries due to a seemingly endless number of turtles blocking their path. However, as the human population has increased, so too has our impact on the world.
On the beach at Playa Cabuyal, I quietly creep back to my assistants so we can resume our beach patrol. Fortunately for us (and for poachers), turtles leave distinctive tracks that appear as dark lines in the sand from a distance. Using these tracks, we find another negra that has emerged to lay 60-80 eggs. We also encounter a ‘lora’ (olive ridley turtle) who emerges, lays her eggs and returns to the ocean within 40 minutes. However, the ‘baula’ (leatherback turtle), largest of all turtles, remains elusive tonight.
Our negra has moved multiple times since we left her. At 5am, she decides to move again, straight into a thorn bush. “Claro!" my assistants giggle to themselves: "Of course!" Black turtles always seem to nest in the most annoying locations. I've already had a bad experience with the Costa Rican vegetation, when a nesting turtle lured me into a toxic manzanilla tree that blistered the skin on my forearms and made my eyes burn for eight hours as though they'd been sprayed with mace.
Crocodiles, sharks, stingrays and jaguars are also potential threats, not only to the turtles but also to the biologists who study them. Poachers are always a major concern. In 2013, Costa Rican environmentalist Jairo Mora Sandoval was abducted and murdered while protecting nests on Moin Beach in the Limon Province. The incident sparked international outrage and led to an increase in protections for both turtles and conservationists.
Tonight, however, the beach is deserted. Our negra begins to widen the bottom of her egg chamber, creating an upside-down lightbulb shape. She will begin laying any time now. One of my assistants lays behind the turtle ready to count eggs and mark the nest site, while the other prepares to measure and tag her. After a few minutes, the first egg, slightly larger than a ping pong ball, drops into the nest. At first, she lays one egg at a time, but eventually they come out in spurts of two or three.
When she is finished, the turtle pushes sand into the nest, packing it down with her rear flippers. With the egg chamber filled in, she takes a short break before beginning to camouflage the location of her nest. Our negra throws sand as though she is body pitting but moves forward sporadically, slowly filling the body pit behind her. Turtle eggs are an easy snack for numerous animals, ranging from crabs to racoons, and especially humans.
Turtle eggs are still a delicacy in Costa Rica. Locals can still buy eggs sourced from the arribada (mass nesting event) at Ostional, in which tens of thousands of olive ridley turtles lay their eggs in the same week. Harvesting these eggs is legal for licensed locals, but only for the first two days of the arribada. These are sold as aphrodisiacs in bars for around 500 colones (US$1) each. Prior to the introduction of anti-harvesting laws in 1966, turtle eggs were used extensively in baking and are said to have made the fluffiest cakes.
Unfortunately, our negative impact on turtle populations no longer stems solely from direct influences such as hunting or egg harvesting. Warmer temperatures caused by climate change will alter sex ratios and reduce hatchling success ‒ quite a problem when already only 1 in 1000 hatchlings survive to adulthood.
Indirect impacts such as pollution, particularly plastics, kill thousands of marine creatures per year, turtles being no exception. Leatherbacks regularly choke to death on plastic bags they mistake for jellyfish. Dr Nathan Robinson, station manager for the Leatherback Trust, recently released two videos of a drinking straw and a plastic fork being removed from the nasal cavities of two olive ridleys that he was working with.
Even with the invention and, in some countries, forced implementation of turtle excluder devices (TEDs), turtles regularly drown when caught in commercial nets or when hooked on long-lines. In my two seasons, I helped remove fish hooks from multiple olive ridleys, saw a leatherback with gashes in its shell from a boat propeller, and another scarred by a circular hook that had been caught in its triceps and had later been ripped out.
Many of the threats facing sea turtles are prevalent not only in Central America, but in Australia, too. Despite turtle hunting and egg poaching never being a big problem here, we do contribute to the pollution of our planet and are among the highest CO2 emitters per capita. And along with the rest of the world, we are unsustainably fishing our oceans. Not to mention dredging our bays and reefs and postponing the creation of new marine parks.
Fortunately, with six out of the seven marine turtle species found in our backyard (including ‘Australia’s turtle’, the flatback), we are uniquely placed to play a vital role in preserving these prehistoric creatures and our marine ecosystems.
Recycling plastics, purchasing sustainably caught seafood and using public transport are three simple ways we can all reduce pollution, carbon emissions, and the stress on our ocean populations. For those who enjoy catching their own fish, make sure you dispose of old fishing line responsibly. By taking responsibility for our impact on the world, we will hopefully enjoy seeing turtles glide around our oceans for generations to come.
The sunrise is now well and truly over. Eight hours after emerging from the ocean, our negra has finished camouflaging. Her ‘body pit’ has shifted several metres from the nest, hiding it from would-be predators. The high tide has long since retreated, extending our turtle’s slow crawl back to the ocean by at least 50 metres. As she drags herself towards the water, inch by inch, we follow her, erasing the tracks left behind, making it harder for poachers to discover her nest.
She pauses more often as she nears the water, tiring from the effort of pulling herself through the sand. I can almost sense her relief as the first wave crashes across her. As the turtle eases herself into the water, I catch one last glimpse as she pokes her head above the surface for a final breath.
Exhausted from a lack of sleep and 10-15km of walking on soft sand, we triangulate the location of the nest so we can find it again once it has hatched. We make our way back to camp for breakfast, and hopefully a few hours' rest before the heat makes sleep impossible.