Sea Turtles: Tireless Travelers

Sea turtles travel thousands of kilometres, even between continents, to carry out their mission to preserve their species.  Some of their main nesting beaches are located right here in Costa Rica.  They have inhabited the earth for more than 100 million years, managing to survive extreme climatic changes, including the Ice Ages.  Today, sea turtles are in danger of disappearing from the planet mainly because of man-made causes.  Costa Rica has some of the most important nesting beaches in the world where it is still possible to witness their age-old survival ritual.  On the Pacific as well as the Atlantic coast, hundreds of female sea turtles representing five different species arrive on our beaches to carry out their tireless mission to preserve their species.  For example, Ostional Beach in Guanacaste is considered the main nesting site for the olive ridley turtle, which are known for their large mass arrivals.  Also nesting on our coasts is the giant leatherback turtle, not only the largest sea turtle in the world, measuring up to 1.8m and weighing up to 400kg, but the farthest traveling reptile ever recorded.  Their journey takes them form their feeding sites back to the beach they hatched at in order to lay their eggs.  For example a female found nesting in June 2005 on Samsambo Beach in Surinam, travelled around the Pacific Ocean visiting the coasts of Africa and Europa for a trip of over 9,000 miles, before beginning her return to Surinam.  In Costa Rica, five of the world’s seven sea turtle species can be observed: olive ridley, leatherback, green, hawksbill and loggerhead.  And, because witnessing the egg laying is an event you won’t want to miss, below is information on the country’s main nesting sites and the best seasons to responsibly observe these enigmatic creatures.  

On the Caribbean Coast:Tortuguero National Park

Located 80 km northwest of the port city of Limon, one of the goals of creating this park was to protect this important nesting site of the green turtle.  A smaller number of leatherback and hawksbill turtles also nest here.  The latter is known for its beautifully patterned shiny shell.  The park consists of a very humid tropical forest which is crisscrossed by a captivating system of wetlands comprised of lagoons and canals from which visitors can readily view land turtles, monkeys, crocodiles, caimans, a variety of birds and other animals.  More difficult to observe are gasper fish and manatees.  The green turtle nests between July and October, with a peak in activity in August and September; and the leatherback, between March and June, peaking in April and May.  In the local community there are guides who set-up guided visits in the park.  This system allows tourists to observe turtles laying their eggs at night.  In and around the town of Tortuguero are many lodging, restaurant and ground, sea and air transportation services available.  The latter provided by NatureAir.  

Sea Turtle Nesting from November 2015

It is still possible to observe both the leatherback turtle (Dermochelys coriacea) and the black turtle (Chelonia mydas) nesting at Playa Grande and Playa Caletas, on the Pacific coast.  November is also the last month to observe the hawksbill turtle (Eretmochelys imbricate) on the Caribbean coast.  The hawksbill is in danger of extinction because its’ beautiful shell is harvested and used to make elaborate rings, combs and earrings, among other trinkets.

Homeward Bound…the Cyclical Journey of the Green Sea Turtle

Once upon a time along Costa Rica’s Caribbean coast, there was a man on a boat.  The man was traveling to Tortuguero to pick up supplies when it began to storm.  He didn’t want to turn back, but feared capsizing closer to shore.  Nearing wit’s end, he saw a green sea turtle breach the choppy water beside him.  The man knew exactly where it was headed and cleverly attached the supply list to the animal’s shell.  The turtle delivered the letter to its nesting grounds in Tortuguero, and the man’s son sent the goods the very next day… or so one version of the local folklore goes.  Through residents know better than to disturb an endangered animal on its way to nest these days, the tale illustrates the predictability of a green turtle’s path.  After traveling for thousands of miles through the ocean, these animals return back to the very same beach upon which they were born, allowing researchers – and shipmen - to predict their route with record precision.  A recent study at the University of North Carolina indicates that turtles may be born with internal regional maps imprinted on their brains.  This means that if turtles were to die out in one area, they could not be replaced because relocated turtles would be completely lost.  Another theory is that turtles memorize every last detail of the environment – down to the colors, textures, and chemical compounds – in order to create their own mental map.  Other scientists believe turtles perceive and interpret subtle differences in the Earth’s magnetic field and use them for navigation, similar to hammerhead sharks.  Indigenous legend tells of a turtle statue deep within Tortuguero Hill, a regional landmark and extinct volcano, that lures the turtle back each year.  Intricacies of this reptile’s reproduction cycle were not explored until the 1950’s, thanks to the efforts of Floridian Dr. Archie Carr – the most important figure in Costa Rican turtle conservation.  The zoologist realized the vital importance of understanding turtle migration patterns in order to save them.  Long before satellite telemetry, Carr developed systems to track their trajectories and movements.  He pushed for the creation of Tortuguero National Park in 1975, and headed some of the most important research and turtle tagging studies performed there.  His book “The Windward Road” inspired the creation of the Caribbean Conservation Corporation (now the Sea Turtle Conservancy).  Turtles have long been global symbols of patience, wisdom and longevity throughout human history.  Many argue that their health and wellbeing reflect the overall status of the ocean and the planet; if the sea turtles are in trouble – so are we. 

On the Caribbean Coast: Tortuguero National Park

Located 80 km northwest of the port city of Limon, one of the goals of creating this park was to protect this important nesting site of the green turtle.  A smaller number of leatherback and hawksbill turtles also nest here.  The latter is known for its beautifully patterned shiny shell.  The park consists of a very humid tropical forest which is crisscrossed by a captivating system of wetlands comprised of lagoons and canals from which visitors can readily view land turtles, monkeys, crocodiles, caimans, a variety of birds and other animals.  More difficult to observe are gasper fish and manatees.  The green turtle nests between July and October, with a peak in activity in August and September; and the leatherback, between March and June, peaking in April and May.  In the local community there are guides who set-up guided visits in the park.  This system allows tourists to observe turtles laying their eggs at night.  In and around the town of Tortuguero are many lodging, restaurant and ground, sea and air transportation services available.  The latter provided by NatureAir. 

The Amazing Olive Ridley Sea Turtle

Distribution

Olive ridleys thrive in the tropical to warm-temperate Pacific and Indian Oceans, but are uncommon in the Western pacific and eastern Indian Ocean. They also inhabit the Atlantic Ocean along the west coast of Africa and northeastern coast of South America. Although Olive Ridleys are seen as far north as Alaska and as far south as New Zealand and Chile, their infrequent visits occur only during unusually warm periods. While a few olive ridleys are present in the West Indies, they do not occur in the Gulf of Mexico or in most of the North Atlantic Ocean.

About 3-5 million years ago, when the Isthmus of Panama formed and closed off the Atlantic from the Pacific, olive ridleys and Kemp's ridleys began travelling down different evolutionary paths. We believe that at the time only the ancestors of the Kemp's ridley sea turtle lived in the western Atlantic. In the 1990s, geneticist Brian Bowen conducted studies that suggested olive ridleys spread from the eastern Pacific to the western Pacific and Indian Oceans. Olive ridleys in the eastern Pacific then died out apparently, perhaps owing to climate change or loss of nesting beaches. When climatic conditions improved about 200,000 years ago, olive ridleys expanded out of the Indian and western Pacific Oceans and recolonized the eastern Pacific. At that time, the genetic lineages suggest, they also moved into the southern Atlantic Ocean.

Olive ridleys can be seen at coastal waters, but scientists have reported observing them far out to sea in drift lines of seaweed (Sargassum algae) and floating debris along convergence zones between warm and cold water regions.

While solitary nesting occurs on the beaches of 32 countries, arribadas are found in only a handful. One of the arribada beaches, Playa Nancite in Costa Rica, is protected as part of Santa Rosa National Park. Another Costa Rican beach, Playa Ostional, is a national wildlife refuge, but it is also the site of a village of 90 houses. Ostional's people collect olive ridley eggs in a legal harvest. Little information is available about the effect of this harvest on the turtle population.

In Mexico, olive ridleys nest in arribadas at Playa La Escobilla in the state of Oaxaca. The beach is protected and studies suggest the ridley population is actually increasing. Another large arribada beach, Gahirmatha, is in Orissia, India. The beach is protected by the government but increased fishing activity in the region has drowned many adult turtles. Smaller arribadas of 2,000 - 20,000 turtles occur in other parts of Mexico and India as well as in Nicaragua and Panama.

Because of olive ridleys' nesting behavior it is difficult to accurately count them. They come and go constantly, literally piling up on top of one another. Some fail to complete a nest because there is just no room on the beach. Repeated attempts mean that they can be counted twice or three times. It is also difficult to count solitary nesters because they visit so many different beaches and in such small numbers. There are simply not enough biologists to count them all (or perhaps not enough money to hire enough biologists to count them all).

The most reliable estimates that I have seen suggest that annually there are about 500,000 - 600,000 olive ridleys nesting at Costa Rica arribadas, 450,000 in Mexico, and 135,000 in India. There may be another 40,000 - 60,000 nesting at the smaller arribada beaches and as solitary nesters. Since olive ridleys reproduce once every 1.7 years, on average, the total world population of nesting females is probably about 2 million. If adult males occur in similar numbers, there are about 4 million adults and anybody's guess as to the number of juveniles. Thus olive ridleys are undoubtedly the most abundant sea turtle in the world.

Unfortunately, this large number hides the fact that olive ridleys are in serious decline. Consider that Mexico had more than 10 million olive ridleys around 1950 and India supported about 600,000 olive ridleys as recently as 1994. Indeed, past arribadas of several hundreds to tens of thousands of individuals have completely disappeared in Suriname and South Adaman Island off the coast of Thailand. Ridley populations have declined precipitously in Bangladesh, Burma (Mayanmar), Malaysia, Pakistan, and Sri Lanka.

Life History

Most olive ridleys lay 2 or 3 clutches of eggs each year they nest (2.2 on average), numbering about 110 eggs weighing 1.4 oz. (40g) each. The clutches are laid at intervals of 17-45 days during the nesting season. They usually nest in the open sand but at Playa Nancite, Costa Rica, some turtles nest under trees, a practice that tends to produce male hatchlings. Olive ridleys appear to waddle along as they use alternate flippers to quickly ascend the beach and leave a distinctive track about 30 inches wide. The female ridleys return to nest every year or two.

Hatchlings weigh 0.6 oz (17g) and generally emerge from the sand at night. The pivotal temperatures for sex determination are 86-88F (30-31C) at Playa Nancite and about 84F (29C) at Gahirmatha, India. In Costa Rica, temperatures of 90F (32C) and higher will produce hatchlings that are 100 female. In India, temperatures of 86F (30C) and higher produce 100 females, It takes 50-65 days for an egg to hatch depending upon nest temperature.

On arribada beaches thousands of hatchlings swarm to the sea at once, usually emerging at night. The beach literally spills open and erupts with tiny turtles that quickly fill the ocean. Most biologists think that this behavior has the effect of "swamping" predators, ensuring that many hatchlings survive the gauntlet from the nest to the open ocean miles offshore. The gauntlet begins while the eggs are still developing in the nests, which are so shallow that it is easy for animals to dig them up. Only by overwhelming predators, placing thousands of nests on the beach or by hiding nests one at a time on widely scattered beaches, can olive ridleys hope to avoid their many predators.

At sea they face hungry fish. Here too, perhaps, the swarm of hatchings provides safety in numbers, as a fish can take only one turtle at a time.

COTORCO Volunteer Reviews

Volunteer: Holly Coleman

Review: I have been coming to volunteer at Carate a few weeks now and I find it so rewarding to come and patrol the beaches and help out the local community. I especially enjoyed helping out the beach clean as it was such a community effort.

Volunteer: Marjone Laroque-Plante

Review: I really enjoy volunteering at Carate. The location is beautiful, everybody is very nice and the turtle patrols are very helpful for their conservation.

Volunteer: Yeicol Ramirez Arauz

Review: Ok trabaje en el vivero porque necesito el trabajo al igual que me gustan muchos las tortugas más trabajar con ellas. Pienso que el vivero es demasiado importante porque hace que cuidemos los haccos y que aigan muchas tortuguitas también trayendo los huevos al vivero no podrán robarlos es algo que beneficia mucho a las tortugas marinas.  Me gusta mucho trabajar para el proyecto de tortugas COTORCO aprendí demasiado de tortugas aquí en el proyecto espero todas las anos creca mas y más muchas gracia. 

Volunteer: Alex Lusty

Review: Volunteering at Carate has been very rewarding. I especially enjoy the turtle patrols and have seen so many Olive Ridleys.

Volunteer: Lisa Forsyth

Review: I have enjoyed volunteering at Carate, especially the turtle patrols. We saw 2 Olive Ridley turtles, amazing experience. The people and the location are beautiful. I hope to come back.

Volunteer: Nicola Wibberley

Review: Witnessing a turtle heaving herself onto the beach and creating a nest, protecting it and maneuvering herself back into the ocean was one of the most humbling experiences ever! We went night patrolling today with Jorge and 2 other tourist. We found a Lora turtle laying her eggs and we put the eggs in the hatchery. I learned the principles of how to take the turtles information when she lays her eggs. This is my second day volunteering so far. Tomorrow I am looking forward to help paint the signs! Amazing experience so far!

Volunteer: Jan, Francoise, Cedric

Review: We are a German-French family living in Lion/France. Our week spent with Phoebe and the people of COTORCO was a rich experience. Very welcoming Phoebe showed us her passion for turtles. And the engagement and a good humor of COTORCO people who shared it with us. Thank you all for these very special moments in Carate!

Volunteer: Becky Holland

Review: We started our 6-hour shift at the hatchery as the sun was setting over Carate beach. The sky was washed with pastel yellows and pinks. Once it was dark, we started to walk the beach and it wasn't long before we saw our first turtle of the night. Her nest had to be relocated as she dug by the shoreline and the sea was flooding her nest.

Further down the beach we saw another turtle digging, this time though she picked a good place to lay. We watched as go 4 ball sized white eggs dropped from the turtle into a carefully dug chamber. Once she was finished she covered her nest and patted down with her flippers.

With the full moon above us, we no longer needed to use our red lights to see. We saw one more turtle laying before we finished our patrol and headed back to the cabins for much needed sleep.

Volunteer: Yeicol Ramires Salavar

Review: OK trabaje en el vivero porque necesito el trabajo al igual que me gustan mochos las tortugas más trabajar con ellas. Pienso que el vivero es demasiado importante porque hace que caidemas los huevos y que again muchas tortuguitas también trayendo los huevos al vivero no podían robarlos es algo que beneficia mucha las tortugas marinas. Me gustó mucho trabajar para el proyecto de tortugas Cotorco aprendí demasiado de tortugas aquí en el proyecto espero todas los años cresla mas y más muchas gracia. ;)

Volunteer: Nadine

Review: I enjoyed any time at Carate very much! I like the beautiful nature and the people here so much. All off the were so friendly. And it was really exiting to do the patrols in expectation to see a turtle :)

Volunteer: Sophia

Review: I was astonished when I first saw the sea turtle during the night patrol. I've never saw one in "real life" before and it was a magical moment. I've never felt so harmonious with nature and the environment before. Everyone who gets to experience this should cherish this moment forever. !Pura Vida!

Volunteer: Patrick Jeshe

Name: Hatchery name: Will-A-Way! It was a special experience taking part in the turtle project in Carate, with the beautiful sunrise and the exotic animals roaming around. An unforgettable experience!