Costa Rica: First clutch saved

Covered in black sand on knees arms and faces, the Costa Rican Biosphere Expeditions team practices digging perfect replicas of sea turtle nests on the beach, to prepare for our shifts guarding the fenced hatchery. We all lie face down on the sand and dig a vertical tube with one arm fully extended, straight down, as far as we can reach. Then we excavate a rounded cavity to one side of the base of the tube, like a boot. The holes we create replicate the holes made by female leatherback turtles, who use their 75 cm hind flippers like a hand, to deftly scoop sand from the bottom of the tube.

Fabian, the lead scientist, let us feel the hole he dug in the sand to test what the perfect example of an egg cavity should be like. Fabian reaches into everyone’s hole and gives people tips for perfecting the shape. “Make your base a little longer and a little wider wider” Fabian suggests to me after testing my first try. Once we perfect our holes and pass Fabian’s checkout test, we sprinkle sand back into the hole, like a mother turtle gently covering the eggs. Tapping the top of the hole down with a fist, we finally graduate turtle nest building class and we wade into the waves to splash black sand off sandy limbs. Barb, Phil and Cynthia laugh as they get knocked around by the strong surf and emerge beaming. But we are still not completely ready to be hatchery guardians.

Fabian points out that the fence around the hatchery keeps out predators such as raccoons or dogs. Each nest is covered by a white basket-like cylinder over the top to stop smaller predators and pests, such as crabs or insect larvae, from attacking the eggs. The baskets covering each nest also corral the emerging baby turtles, so they can’t flipper to the ocean and the citizen scientists can record how many hatchlings emerge from each nest as well as measure 15 of them from each. During their hatchery shift, every hour, guardians peak into each basket to see if a nest might be hatching. If it is, they call the other citizen scientists on the radio so people can come help, because there can be over 80 tiny turtles clambering to escape the confines of the basket. Some lucky hatchery guardians will get to be the proud adoptive parents of a new clutch of eggs, brought to them by other citizen scientists patrolling the beaches looking for turtles laying eggs. They can then employ their newfound skills as a nest cavity excavator.

Carved into the vegetation bordering the beach, the fenced-in hatchery now protects over 7,000 sea turtle eggs. As the nesting season continues, the hatchery will protect over 10,000 eggs, and statistically each year only ONE in 10,0000 baby turtles will survive to reproduce. Each clutch of 80-100 eggs is removed from a natural sea turtle nest and re-burried to incubate in the sand within the guarded hatchery. Citizen scientists will keep watch in the hatchery 24 hours a day for the 9 months of the turtle nesting season. Each nest takes between 55-100 days to hatch depending on temperature. Warmer weather helps the eggs develop more quickly, and during cloudy cool weather, incubation is slower. We hope that hatchlings will emerge while we are here.

Later that day, after a delicious traditional Costa Rican dinner prepared by chef Johanna, we check the schedule written on a whiteboard to see who is on hatchery duty and who on beach patrol that night. Beach patrol shifts last from 2-4 hours depending on if it’s light out or not. Daytime shifts are 2 hours , night shifts are 4 hours. Our citizen scientists cover the 4 hour night shifts this evening, starting at 21:00 and running through the dawn after 06:00. Some people get ready for their upcoming hatchery duty donning long pants and red headlights and others take a nap to wake up in the middle of the night to start their shift.

The next morning, during breakfast, we all chat about how everyone’s evening went. We learned that during the hatchery shift from midnight to 03:00 Phil, Barb and Cynthia were lucky enough to receive a bag filled with pool-ball sized turtle eggs, from citizen scientists who just carried the 6 kg bag for over two hours. Phil started work quickly and dug the long vertical shaft with the boot-shaped hollow for the eggs to rest within. Each of the three guardians took turns placing eggs into the hole, counting each out loud: “….88, 89, 90!” They carefully placed sand over the eggs and marked the new nest with sticks. They tagged the new nest with a number and letter designating its place in the grid of the hatchery. Everyone was  excited that our team helped protect this clutch of 90 eggs from poachers, stopping this particular endangered treasure from being sold on the black-market as snack.

In the afternoon, our crew cut and sewed baskets to protect the nests. Once the handicraft was complete, we ventured to the hatchery and fixed the edges of the new baskets around the tops of the nests buried the previous nights. The first clutch of eggs of our expedition is now safely tucked into its new resting spot in the hatchery. Some day in the next few months, “our” turtles will venture out into the ocean. Perhaps one of ours will be the one in 10,000 that will return to this beach to lay eggs again.