My Week as a Marine BiologistAuthor: GingerD
Date of Trip: December 2012
Tortugueros Las Playitas Sea Turtle Project
Todos Santos, Baja, Mexico Dec 4-11, 2012
Sea turtles have inhabited the Earth for 65 million years - they even swam with the dinosaurs! Sadly, many turtle species are now endangered. The Pacific Leatherback population has declined by 90% in the past two decades. Their favorite food is jellyfish and turtles can die after mistaking plastic bags for food. They can live up to 100 years and travel thousands of miles in the ocean on feeding migrations. Leatherbacks can grow to 6 1/2 feet long with a wingspan of 10 feet and weigh over 1100 pounds. The Olive Ridley species is smaller at about 2 1/2 feet in length weighing about 100 pounds. The Black and Green sea turtles are actually the same species and more of a medium size, falling between the smaller Olive Ridley and the larger Leatherbacks. These are some of the facts I learned as a volunteer on the project.
Now I will tell you about my hands-on experience.
The day started early at 4:30AM as the roosters next door awakened me. German and I would take the ATV in the chilly morning air to patrol 20 miles of beach, looking for the turtle tracks so we could locate nests. The eggs were then dug up and transferred by bags to the greenhouse on the beach, where they were then reburied to the same depth, about the full length of my arm. The nest was marked with a stake showing the date and the number of eggs. A typical nest is about 100 eggs and the incubation time varies from 50-70 days depending upon the species. The incubating greenhouse helps ensure that turtle nests will hatch successfully as it provides a warm and safe environment. Without moving the eggs, many winter nests would be lost due to cold beach sand temperatures. The sea turtles used to come in further south to lay their eggs in the warmer sand, but with all the development in the Cabo area, they were forced to move further north away from lights. Bright lights will confuse hatchlings and they will actually lose their way to the sea. Also, a warmer nest temperature increases the number of female hatchlings.
The Las Tunas area in Todos Santos is a good place for the greenhouse as the waves here are too strong for swimming or surfing, but some of the early morning fishermen still drive on the beach and that could compress turtle nests and suffocate hatchlings, which is why we were out before sunrise. By 7:30AM we were back at the casita in town, so I could make my breakfast in the outdoor volunteer kitchen and get prepared for my day, changing out of warm clothes and packing up water, food and a book.
Inside the greenhouse Francesca would drive me back to the beach at 9:30AM and I would set up under the palapa with a table, a chair and a pan of warm, damp sand. (There were no facilities but the pan was for the baby turtles that hatched during the day.) My duty was to monitor the nests inside the greenhouse. There was 1 Black Sea Turtle nest, 5 Leatherback and about 40 Olive Ridley nests in the greenhouse while I was there. Every 1/2 hour I would need to go inside the hot sauna-like greenhouse and plug the probes from the sand into a meter to record temperatures. I would then run my fingers down thru the sand on top of the nests that were due to hatch, feeling for baby turtles coming up. As the turtles emerged I would get them outside to the shaded pan. They were just the size of the palm of my hand and would start squirming around and looking up at me. These nests were laid in October and were Olive Ridleys (Golfinas).
At 4:30PM, Francesca would return and the nests that had turtles emerging would be dug up so we got all the turtles out for the sunset release. We needed to lay the shells out in rows and get accurate counts and record all the information. Sometimes when we got to the bottom of a nest we were digging out, there would be a couple of eggs where the turtles were still hatching. As I held the egg, the turtle would hatch right into my hand.
By now we had many tourists gathering to participate in the release, so we would spend about an hour giving out information, answering questions and accepting donations for the project. We would then all go down to the shore where we drew a line in the damp sand, had everyone gather behind the line, “wash” their hands with dry sand to remove oils and give everyone a baby turtle to put down and watch as they made their slow journey down the sand and into the ocean. The females will mature in about 15 years and will return every 2-3 years to this beach where they were hatched.
It was a magical experience for everyone and the beautiful sunsets always enhanced it even further. One day we had a distressed nest. No turtles had emerged and they were overdue so we dug up the nest to check it. About 60 eggs on the top of the nest were infertile and were weighing down the hatchlings below. We rescued about 40 baby turtles at the bottom of the nest but a couple of them were already dead. The female stores sperm and when she produces the eggs, she fertilizes them. After she has laid her nest, she returns to the ocean and produces more eggs and again fertilizes them and comes in to lay a second nest. By the third nest, she may not have enough sperm left and so only some of the eggs get fertilized.
One evening Francesca couldn’t get there in time so I had to dig up a nest, count and record everything, and handle the tourists and release all by myself. On my last day there I had 3 nests hatching all at the same time so I was super busy with keeping the hatchlings and records all separate. It was indeed the grand finale with about 300 hatchlings heading into the sea at sunset. German and Francesca were very appreciative of the work I did as I was the only volunteer there that week. The volunteer before me spent an entire month by herself. So although it was long, hot days of work, the experience was truly unforgettable. And yes, I did feel like a marine biologist for a week.
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