By Meera Dolasia
Every year four of the world's seven species of marine turtles arrive on the Pacific coast of Costa Rica to nest. Among them is the Olive Ridley, an ancient turtle that has been around for more that 100,000,000 years and was at one time amongst the most prolific and abundant of all turtle species.
Thanks to extensive fishing and egg harvesting, the population of this ancient turtle that was once believed to be as high as ten million was decimated so badly that like other sea turtles it had to be placed on the 'endangered' list. Then about two decades ago, a rather controversial sounding plan was put in place by the conservationists at Costa Rica's Ostional National Wildlife refuge for the 8 X 200 meter wide Ostional beach where these turtles arrive by the hundreds of thousands twice a year - Once between January to April and the second time between May to December for an ancient reproductive ritual that the locals call arribadas ('arrivals' in Spanish).
The earlier season is usually a shorter one, spanning less then four days with about 5,000 turtles coming ashore to lay eggs. The second, which is during the wetter months of the year, involves more then 300,000 turtles and can last anywhere between 8-10 days. Sometimes the turtles even arrive twice during the rainy season!
Not only that, the females lay not one, but clutches of 100 eggs at a time, which means that over the course of the nesting season there can be millions of eggs strewn all over the beach. While this is great news, herein lies the problem. Because the turtles all rush in droves, they tend to trample over existing nests, which not only destroy the previous eggs, but also, cause them to rot and contaminate the surrounding sand. This in turn diminishes the hatching success of the surviving eggs to just 1-2%! More....