When a rare leatherback turtle, weighing 1,000 pounds with a shell measuring more than a meter across, crawled back into the Caribbean Sea last month after laying her eggs on a tourist beach in Santa Marta, no one knew the impact she had created.
Just finding her nest was a challenge – taking biologists and volunteers two days of digging to discover the place she laid her eggs one meter deep in the sand. Unlike other turtle species, leatherbacks typically lay their eggs in the middle of the beach, not further away from the water where the vegetation helps regulate the temperature of the nest. Considering that leatherbacks’ nests receive direct sunlight, the female lays two types of eggs “to prevent her eggs from cooking,” says marine biologist Carmen Lucia Noriega. Viable eggs, those with the potential to develop an embryo, are laid first. Then come several dozen nonviable eggs that create a protective blanket to both deceive predators and maintain the temperature of the nest. Of the 100 eggs she laid, 77 were considered viable.
Due to the discovery of unstable groundwater below posing an enormous risk to the eggs, a unanimous decision was made to remove the eggs to ensure the greatest number of hatchlings. With logistical support from Universidad Jorge Tadeo Lozano, CORPAMAG, and Petrobras, the eggs were relocated to the Mundo Marino Aquarium in Santa Marta. There they were placed under the care of biologists as part of the Programa de Conservacion de Tortugas y Mamiferos Marinos directed by marine biologist Aminta Jauregui.
Relocating 77 eggs is not as difficult as one would think. “There is a 72-hour window where you can safely move the eggs without affecting their polarization,” said Noriega. “After this, there’s a higher risk of harming the embryo.”
Past experience has shown that the best, most successful incubators have been the simplest: portable Styrofoam coolers, with sand lining the base. The incubators were placed in an air-conditioned laboratory where the turtles’ natural environmental conditions were replicated as best as possible. This factor, Noriega explains, allows for a mix of sexes to hatch. The ambient temperature in the last weeks of incubation is what determines whether a reptile’s embryo develops into a female or male. Higher temperatures result in females, with males resulting from cooler conditions.
After a 55-day incubation period, biologists were able to begin the revision process. More than half of the viable eggs contained embryos, and on June 9 the aquarium welcomed 36 healthy hatchlings. This is a conservation victory because, on average, only 30% of viable eggs hatch in nature. This is the first time Colombian marine biologists have raised this specific turtle species. “I am thrilled,” said Noriega, “[because] it is a great opportunity to witness an event that is difficult to see in our region, especially because we don’t usually have this species in the laboratory.”
Upon hatching, the turtles were placed into one of four large buckets. Each bucket comes equipped with a filtration system where circular currents help the turtles move, imitating their natural habitat. As leatherbacks are born on the move and have the largest migration trajectory of all reptile species, they require large amounts of food from birth. And, it turns out, leatherbacks are quite the fussy eater. “They have a very specific diet, because as soon as they hatch they leave the nest immediately” said Noriega. Their favorite meal is jellyfish, but there isn’t jellyfish here all the time, “so based on international experience, we are generating jelly, made from a mix of algae, octopus, squid, and shrimp,” she says.
An amusing observation, Noriega revealed, is that the turtles sleep until mid-morning. Even if the biologists place food in the buckets at 7 am, they won’t eat.
Their release date into the ocean remains uncertain and depends on how fast they reach an appropriate size that will ensure their survival. Leatherbacks are unique, compared to their cousins, in that they have a flexible, blue-black rubbery shell. This is a great advantage as it allows them to grow much bigger, reaching up to two meters, and better adapt to the low pressures and cold temperatures when diving to depths of 1,200 meters to feed.
According to the International Union for Conservation of Nature and Natural Resources’ list of threatened species, leatherback turtles are considered critically endangered. The conservation efforts in Santa Marta, therefore, were joyous. “It’s been more than 20 years since someone has reported a turtle nest in this area and shows that conditions are becoming favorable once again for females to lay here,” said Noriega. As females prefer to lay in the dark, typically during a new moon, turning off hotel beach lights greatly improves the possibility of females returning to nest.
With the collaborative efforts of scientists, environmental initiatives, and most especially, an informed public, species facing extinction, such as the leatherback, stand a chance to recover their population numbers.
