A scientific project funded by the BBVA Foundation and conducted by a team from the Spanish Council for Scientific Research (CSIC) explored around 100 kilometers of practically uncharted Atlantic beach in the north of Colombia and south of Panama between the years 2006 and 2007. In the course of their work, they came across extensive nesting grounds that bring new hope for the survival of the leatherback turtle. This species suffered a grave decline in the twentieth century and is among those considered by the World Conservation Union to be in critical danger of extinction.
The project has permitted the documenting of around 6,000 new annual nests in the zone. The most important site is Armila beach in southern Panama, which is being managed by the indigenous Kuna community with stringent protection measures in place for the turtles. Armila is home to one of the highest known densities of leatherback nests, with a similarly high birth success rate. It is also an exceptional model of ancestral co-existence with a positive conservation impact for a seriously imperiled species.
The results of this study confirm the Central American Caribbean as the world’s fourth largest nesting zone for the leatherback turtle after the Guayanas, Gabon and the island of Trinidad. However the success of Armila was not repeated at remaining beaches along the exploration route, where the team detected severe disturbances that impair turtle nesting – including grave cases of nest raiding – and could jeopardize the future of this leatherback population.
The BBVA Foundation project, funded under its Call for Research Proposals in Conservation Biology, has been written up in the scientific journal Biological Conservation with the title: “Globally significant nesting of the leatherback turtle (Dermochelys coriacea) on the Caribbean coast of Colombia and Panama”, citing as authors Juan Patiño, Adolfo Marco and Liliana Quiñones, researchers at Doñana Biological Station (CSIC), and Brendan Godley from the Centre for Ecology and Conservation at the University of Exeter, United Kingdom.
An exceptional creature
The leatherback (Dermochelys coriacea) is the world’s largest turtle, with some individuals reaching two meters in length and weights of around 800 kilos. They can live up to 100 years, nest in topical zones and make the longest ocean crossings of any marine vertebrate, returning 11,000 kilometers to lay their eggs on the beach where they were born. They are also resistant to very low temperatures, meaning they can be found in all the world’s oceans. In fact, some have even been sighted near the polar regions.
The leatherback turtle chooses hot tropical beaches to make its nest. It does not breed every year, but when it does so stands out for the large quantity of its nests—normally around seven (with cases of up to 11) per season, excavated at intervals of 15 days. Each nest has between 65 and 110 eggs and can weigh between 5 and 10 kilograms.
Before covering the nest, the leatherback places smaller fake eggs on top of its own clutch, so they are protected during the development phase. It digs the deepest nesting pit of any sea turtle, up to one meter deep. This means the hatchlings born after two months’ incubation must make a Herculean effort to scale the near vertical walls to the sandy surface. They then have to make their way into the ocean waters, where they disperse and swim for over ten years until reaching maturity. They then return to the beach of their birth to begin their own breeding cycle.
Exploration and discoveries
The exploration supported by the BBVA Foundation took place between the towns of Anachukuna, in the Kunayala area of southeast Panama, and Mulatos in Colombia, during the breeding seasons of the last three years.
Prior to the study, the zone was reckoned to harbor between 100 and 250 nesting females, though many beaches were virtually unexplored. But this latest census lifts their annual number to between 1,140 and 1,300, making it a major Atlantic Ocean breeding ground and refuge for the leatherback turtle.
Of the seven nesting beaches investigated, Armila (4.5 km length) is the most abundant in annual nests, which number from 3,600 to 4,040 units or 60% to 67% of the area-wide total. Armila’s nesting density, with an average of 900 nests per kilometer of beach, is also exceptional—the highest in the Central American Caribbean ahead of Playa Chiriquí, also in Panama, whose 128 nests per kilometer were until now considered the local maximum. Armila also stands out for the high survival rate of nests and the hatch rate of clutches, which borders on 70 %.
- Juan Patino-Martinez, Adolfo Marco, Liliana Quiñones, Brendan Godley. Globally significant nesting of the leatherback turtle (Dermochelys coriacea) on the Caribbean coast of Colombia and Panama. Biological Conservation, 2008; in press DOI: 10.1016/j.biocon.2008.05.012
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