Arribadas: Harvesting Turtle Eggs in Ostional, Costa Rica
The first indication came on a picture perfect Monday afternoon when a solo turtle emerged from the waves on Playa Ostional. She was the first of thousands that would follow soon after sunset. Welcome to Ostional, the arribadas has begun!
The mass arrival of Olive Ridley turtles occurs on only nine beaches worldwide during the week leading up to a full moon. Thousands of turtles return to the beach where they were born. They creep up the coastline, dig a hole and lay their eggs. They cover the eggs with sand and return to the sea.
In Costa Rica, this means harvesting turtle eggs, promoting eco-tourism and biological study. All of these interests are carefully planned and executed by caring volunteers. A diverse cadre work together to gather eggs, protect the beach, escort/educate visitors and observation.
The locals - los Costarricenses (ticos) - have 36 hours after the initial onslaught to retrieve eggs. Because the turtles cleverly camouflage their sandy nest, it is difficult to locate buried eggs. The ticos walk the beach, digging their heels into the sand and locate the nests by feel. When the eggs are extracted they are loaded into large bags that the ticos carry around on their shoulders. The eggs are surprisingly robust and resist breakage because they have a flexible shell.
The shells are covered in a sticky membrane which the ticos wash off in the ocean by dousing the bags. Once clean, they are separated into smaller bags of 200, which is how they are sold. As of this writing (December 2003), each bag costs 4,200 colones (approx. US $10.00). The eggs must be distributed quickly and/or kept cold if possible as they will spoil in three to four weeks.
The entire process is completed in an afternoon. After the sun sets, the beach is cleared for another night of egg-laying. Visitors are permitted to watch the action at night, but must be accompanied by a guide. Biologists are also on the beach counting eggs and reading the tags previously placed on the animals. All this activity continues with minimal interruption to the turtles' homecoming.
The arribadas is an amazing event and Alana's favorite part of our trip to Costa Rica
Making Good on the arribadas
As part of a plan designed to help save the Ridley, the residents of Ostional hold a unique license to harvest the turtles' eggs and sell them. Because so many turtles pack the beach during the arribada (or egg-laying) season, eggs laid on the first few nights are often destroyed by turtles on subsequent nights; at the same time, incubating eggs are often dug up and destroyed when another arribada occurs before the first batch has hatched. To make matters even worse, poaching by locals was threatening to reduce the already severely stressed Ridley population beyond the point of no return.
In 1987 the government of Costa Rica approved a plan to permit residents to harvest a quota of eggs - those that would likely be destroyed anyway - during the first 36 hours of each arribada. By removing these eggs, bacterial infections have been reduced and significantly more eggs are hatching.
The local community has benefited from the new income, fostering support for conservation, while the presence on the market of eggs bearing the stamp of approval has undercut the market for eggs poached from other beaches.
Excerpt taken from:
Baker, Christopher P. National Geographic Traveler's Costa Rica National Geographic; Revised edition (March 2003)
NOAA - Olive Ridley Sea Turtle
U.S. Fish & Wildlife Service - Olive Ridley Sea Turtle
Douglas Robinson Marine Turtle Research Centre
ARRIBADA - FAQ