Ostional is one of the only three beaches in the world where the small leatherback turtle nests.

Mayela López, AFP/para LN
 
There are more nests than capacity on this beach in Guanacaste

Ostional is overrun by nesting leatherback turtles. 

In 20 years the amount of colonies arriving every month has increased ten fold. Despite the fact that there are more nests, the amount of offspring has not increased.

Alejandra Vargas M.
alevargas@nacion.com

The night time arrival of more than 300.000 leatherback turtles during the last week of September at Playa Ostional, in Nicoya, Guanacaste, is a reason for the country to celebrate, but is a cause for concern for scientists.

The residents of this community have congratulated themselves for the ten fold increase of colonies and eggs in the last 20 years. They attribute this to the care they have given to the beach and turtle nests.

“We are very happy and think that the cleaning of the beaches has worked and how we have protected the nests in the last 20 years. This economically benefits all of the community and helps with tourism,” said Tomás Chavarría, from the Ministry of Public Security (Ministerio de Seguridad Pública).
 
“The mass arrival of turtles happen once every month (11 times a year) and not only during the nights of the third quarter of the moon, as it was traditionally,” assured Chavarría, who has lived there for 41 years.  

Nevertheless, the happiness because of the increase in nests of an endangered species is also joined by an enormous amount of concern.

Biologists and specialists have stated that the enormous amount of turtles arriving at the beach is a serious problem because of overcrowding. 

“The current nesting exceeds the capacity that Ostional has to receive so many turtles.  In one square meter there can be up to four nests with between 80 and 100 eggs”, said Gerardo Chaves, scientist of the Biological Station at the Universidad de Costa Rica (UCR).

“Hundreds and thousands of turtles arrive during the night, but that has resulted in the birth of more offspring. In fact, the mortality rate is much higher because turtles are arriving and destroying already existing nests or they are contaminated with fungus and bacteria”, he said.

Now Playa Ostional is not enough. In the past 50 years the nesting areas has expanded by 800 meters to seven kilometres, which is the full extension of the beach. 

Scientific investigations have indicated that when a beach becomes saturated with nests the turtles stop coming to that particular coast. This has already happened in playa Nancite, located closet to playa Ostional, on the Pacífic.

“The descent of turtle nests in Nancite reflects that this is a natural cycle and does no last forever”, detailed Carlos Drews, Regional Coordinator for the Conservation of Sea Turtles in Latin American from the Worldwide Fund for Nature.   .

“¿Why did nesting begin there some 50 years ago? ¿Why does it increase or decrease? ¿How long will it go on for? There are many unanswered questions,” said Drews.

“The leatherback turtle is an endangered species and only nests on three beaches in the world. Although it may seem like the nests in Ostional are a lot, this does not mean that the population has recovered. The suggestion is that the community learns not to depend on this activity alone.” stressed Drews.

The next mass arrival of leatherback turtles will be on the 23rd of this month.