Volunteering in Costa Rica - Olive Ridley sea turtle project

on 17 Oct 2012 

Arribada! Arribada! flotas flotas!

(Spanish – English translation: arrival , fleet)

You will find Olive Ridley sea turtles on any side of the coast in Costa Rica (and in many other countries – including Australia!), but it is in Ostional, a remote town on the Pacific coast where, ‘arribadas’ occur. Arribada, meaning ‘arrival’ in Spanish occurs once a month usually at the 3rd quarter moon. Here, thousands of Olive Ridley turtles come up at night to lay their eggs. It is one of only seven beaches in the world where arribadas occur and one of the three most significant – the other two being in Mexico and India.

An arribada will occur almost every month – with the exception of the peak of the dry season in December and January. During a usual arribada, you might see 1500 or so turtles throughout the course of the night – lasting anywhere between 3 and 7 days. But, in the peak of the wet season (September – October) numbers get as high as 50 000 a night and subsequently, occur in the day time also (with nesting activity unusually occurring at night).

Another great thing about this time of year are the huge hatching events (resulting from the previous month’s arribada). All you need to do is stop, wait and watch the sand. A “bubbling” will soon begin and the sand simply caves in on itself, followed by, you guessed it, a torrent of hatchlings all trying to clamber up to the surface determined to get to the water. Unfortunately, their chance of reaching full adulthood (even if they make it passed the vulchers and the dogs) to the water) is extremely low.

When an ‘Arribada’ is not occurring – solitary nesters come up on all other evenings, with a very quiet period occurring a few days before an arribada hits. A common arribada night starts once the sun dips into the ocean. You might see your firstly turtle awkwardly crawl her way up to the beach after a day (or two!) of mating in the water. She is already exhausted, and now, a ‘turtle out of water’ must find a spot to nest. Things really crank up though at night, at the peak of high tide – where there are so many turtles you need to watch your step. And if you’re working a turtle, be prepared to shove them away as they forge ahead with only one thing on their mind – to lay eggs!!
The process of laying eggs, starts with the making of the body pit, where she is essentially nestling into a spot to lay and start digging – it involves a swishing around of her body and flippers – resulting in sprays of sand towards anyone who dares to get too close. She then digs with her flippers methodically and instinctively, curving her flippers to dig and throw out sand one move at a time. It is then you get a sense of how agile and strong her flippers really are. After about 15 minutes of digging (on average) she starts laying. Average nests are about 60-130 eggs full, their ping-pong replica eggs can with stand the crowded nest due to their soft texture and light weight. Once she is done, so begins another slow process of covering the nest and my personal favourite, the “covering” of the nest with their full weight and flippers – resulting a thunderous stomping heard all along the beach (when you’re talking about thousands of turtles that is).
It is during this activity that monitoring by the turtle program staff and volunteer is performed.

According to locals and sea turtle conservationists, little is known about their behaviour and why an arribada beach becomes one at all.
So in the dark, with the aid of red cellophane covered torches and headlamps, we record information about their behaviour – e.g. their measurements, how many eggs were laid, how deep was the nest and long did it take her etc. There’s also a tagging project in place (since 2009) to determine whether or not arribada turtles go back to the same beach over and over – or if they are solitary nesters too.
What is also fascinating – aside from these huge nesting events – a sight I feel privileged to have seen, is the beach and town this all takes place, Ostional.

Ostional is a very small, very remote town about 6 hours from the capital city of San Jose. As mentioned, it is also a wildlife refuge of about 1, 100 hectares (300 ha land, 800 ocean). Access is difficult, especially during the wet seasons where rivers flood and the roads start to resemble an obstacle course. Ostional is also Costa Rica’s only national wildlife refuge that has a community living on it. The town of about 500 people go back generations before it is was ever declared a refuge and so, they remain there – having no where to go if the government decided to kick them off. There are elements in place though to aid the turtles. No lights on the beach, no houselights too close to the shore and most importantly, guards to try and stop turtle egg poaching.

Unfortunately, commercial fishing and illegal fishing are a big threat. Turtles get caught in the nets and drown, and resources provided by the government are minimal so coastguards can rarely prevent a lot of the turtle deaths that are occurring. Strays dogs are also a big issue. They dig up the nests, gorge on eggs and worse of all, eat the hatchlings. And that’s on top of the natural predators, specifically vulchers who are a constant presence on the beach, waiting for their next feed.

The work being done by just three paid staff is impressive. They are dedicated and live their life by the ‘turtle’ clock – either living on the government station or nearby with their families. Better yet, they are assisted by dozens of volunteers every month who assist in the monitoring project, beach clean and egg excavations (the gross part of turtle work where un-hatched eggs are dug up and recorded.)
Needless to say, spending 6 weeks of my life there was one of the most rewarding things I have ever done. No wonder Costa Ricans say “pura vida!” all the time… (Translation: pure life!)