Ostional Wildlife Reserve

The beach of Ostional is the scenery for a rarely-seen biological wonder. Around the third quarter of the moon, hundreds, and sometimes hundreds of thousand sea turtles come to one specific mile of beach at Ostional to dig their eggs into the black, volcanic sand.

The Ostional Wildlife Refuge in Costa Rica was created in 1984 to protect one of the world's most important nesting sites of the olive ridley sea turtle.

Only olive-ridleys and their close relatives, Kemp's Sea Turtles, the latter an Atlantic species synchronize their nesting in mass emergences or "arribadas", the Spanish word for arrivals.
(See also: Sea turtles in the Wildlife Guide)

Some days or weeks before the mass nesting, the "flotilla", an increasing number of turtles, congregates close offshore.
After some days, prompted by some secret signal, the "arribada" will begin. At first, a few hundred turtles will come out on the beach, followed by a steady stream of animals for the next three to seven days.

Turtles nest at Ostional year round, but peak time is during rainy season. From August through December arribadas occur regularly once, sometimes even twice a month and the number of nesting females are in the range of hundreds of thousands as opposed to tens of thousands for the dry season months.

The largest "arribada" thus far recorded in Ostional, took place in November 1995 when a calculated 500 000 females came ashore.

The turtles generally ride in on the high tide at night but during an arribada they start arriving around 4 p.m. and keep coming until 7 a.m. the next morning.

Used to a life in the ocean, the turtles painfully drag their heavy bodies over the beach until they get over the high tide line. There, flicking clouds of sand, they dig a nest with their flippers to deposit about 105 white, ping pong-shaped eggs.

Over the course of a five-day arribada nesting turtles will leave up to 10 million eggs on the beach of Ostional.

Amazingly, Ostional is the only beach in the world where egg poaching is legal. Scientists found out that most of the eggs deposed in the first nights of an arribada are destroyed by subsequent turtles who dig their nests.
Therefore, since 1987, the government of Costa Rica allows on an annual, temporary suspension of the international ban on turtle-egg taking that the community of Ostional may harvest the doomed eggs on the first two dawns of an arribada. In return, the community must protect the turtles, clean debris from the beaches and patrol day and night for poachers.

The baby turtles hatch within 45-54 days depending on incubation temperatures, which will also determine if they will become male or female. They face varying degrees of success in each of the clutches that are laid in large groups to increase their success of surviving.

In general the baby turtles hatch at night, but it may also happen that you are sitting in the afternoon on the beach and suddenly, next to you the sand becomes live and small heads pop up.

As soon as the hatchlings have struggled out of the sand, the race to the ocean begins. With eyes barely opened, the mini turtles smell the breeze and instantly know the right direction.

Women and children from the community of Ostional accompany the hatchlings as they clamber toward the sea, protecting them from dogs and vultures.

If you also want to help the small turtles you shouldn't carry them all the way to the beach as they need the run to develop their lungs. You can carry them a piece of way over the hottest stretch of sand and let them run the rest just trying to provide them some shade and keep the vultures away.

Having reached the ocean, the mini turtles still aren't safe - the next cast of predators awaits them under water.

Most hatchlings don't reach maturity, but those who make it will remember the smell of their beach. After 10 - 15 years they will return to their place of birth and again lay their eggs into the black sand of Ostional.

Visiting Ostional:

The Ostional Wildlife Reserve extends 15 km along the shoreline, including the beaches of Ostional, Nosara and Guiones. It is only a narrow, 200 m wide strand of beach, but extends inland along the estuaries of the rivers and mangrove swamps, protecting large colonies of birds. Offshore the reserve incorporates another 3 miles stretch of maritime zone.

Without the occurrence of an arribada you can walk alone to the beach which is littered with the white shreds of broken turtle eggs.

During the day crowds of black vultures sit in wait for the small turtles or, impatiently with their beaks, pick and scratch in the sand to get to the tasty turtle eggs.

During nesting season (Aug - Nov) solitary turtles arrive almost every night at Ostional and sometimes the rare and endangered giant leatherback turtles and green sea turtles come to nest as well.

During an arribada you must check in with the ranger booth at the southern end of Ostional where you pay the entry fee of $ 6 and another $ 7 for the guide without whom you may not go to the beach. No flashlights or flash photography is permitted.

How to get to Ostional:

Ostional is a short drive from Nosara. From the Beaches of Nosara, drive 2 kms until the turnoff to Santa Marta to the left. From here it is 7 kms to Ostional. A bridge leads over the Nosara river but there is no bridge over the Rio Montaña which can be impossible to ford in rainy season. Most hotels in Nosara will arrange tours to Ostional when there is an arribada.

Coming from the north, a road goes to Ostional south-west from Santa Cruz or south from Junquillal via Marbella and San Juanillo. For most of the year this road is in rather good condition, but Sept/Oct a 4x4 is advisable.

From Santa Cruz a bus runs daily at noon time to Ostional (3 hours) and returns to Santa Cruz at 5 a.m.

Google Site Search :