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We study the in-water movements of sea turtles, especially hawksbills (Eretmochelys imbricata), mating, nesting and feeding along the Caribbean coast. We survey individuals in-water, tag them, collect morphological data and tissue samples and attach satellite transmitters to a subset of individuals (nesting females and individuals captured in-water) to follow their travels during the nesting season, as well as their (post-nesting) migrations to their feeding grounds.



We study the migrations and in-water movements of the olive ridley (Lepidochelys olivacea), hawksbill (Eretmochelys imbricata), and Pacific green turtle (Chelonia mydas agassizii) populations gathering in front of the Peninsula Nicoya. We survey individuals in-water, tag them, collect morphological data and tissue samples and attach satellite transmitters to a subset of nesting females and male turtles to follow their travels during the nesting season, as well as their post-nesting migrations to their feeding grounds.


We are further interested in conducting a saturated tagging and intense recapture project at Ostional beach to answer some basic and important questions about the nesting phenology of olive ridley turtles that remain unanswered. 


Since 2022, we have been financing the sea turtle hatchery in Ostional that is mainly meant to safely incubate eggs of the critically endangered Eastern Pacific leatherback turtle (Dermochelys coriacea), but is also used to relocate nests of the Pacific green turtle (Chelonia mydas agassizii).


Ostional Beach is known for the synchronized mass nesting of olive ridley turtles, that arrive once a month to lay their eggs in large groups of up to 500,000 females. The resulting high nest density is responsible for the low hatching success of other sea turtle nests on the same beach. Our beach hatchery helps to raise the hatching success. 

Sea Turtle Nesting on the Peninsula Osa (COPROT - Tortugas de Osa)

Since 2020, we are supporting COPROT with their monitoring and conservation efforts of nesting olive ridley turtles (Lepidochelys olivacea) and Pacific green turtles (Chelonia mydas agassizii) on the peninsula Osa.


The Osa Peninsula is on the far south Pacific tip of Costa Rica, one of the most biodiverse areas on the planet. It is home to Corcovado National Park, which encompasses a wide variety of distinct ecosystems including old-growth primary rainforest, palm forests, mangrove swamps, and coastal and marine habitats. With this variety of ecosystems comes numerous endemic and migratory species. The Osa Peninsula alone holds an estimated 2.5% of global biodiversity, with some 250,000 plant and animal species, over 300 of which are found nowhere else on the planet.  

One side of the peninsula faces the Pacific Ocean, with powerful waves and strong currents on wild, pristine beaches that have been largely saved from coastal development. The other side harbours Golfo Dulce (the sweet gulf), the only tropical fjord found on the American continent and an ecosystem with incredibly unique oceanographic characteristics. The gulf is an "inner sea" that sits between the Osa Peninsula and Piedras Blancas National Park on the mainland and acts as a critical site for feeding and reproduction in numerous keystone species, including humpback whales and sea turtles.

The beaches in our conservation area face the Pacific Ocean and are some of the most important index beaches for sea turtle nesting on the Pacific coast of Cosa Rica with over 7,000 nests recorded annually from the olive ridley and Pacific green turtles.


 In 2020, COASTS reinstated a formal monitoring and conservation program for sea turtles nesting at beaches in the Gandoca-Manzanillo Wildlife Refuge. 

The Gandoca-Manzanillo National Wildlife Refuge (RNVSGM) is located in the very South of the Caribbean coast in Costa Rica and is known for its rich biodiversity and pristine habitats. RNVSGM still has one of the last patches of primary rainforest and a large area of mangroves. It also harbours three resident sea turtle species that are using the RNVSGM as feeding and nesting site, hawksbill turtles (Eretmochelys imbricata), leatherback turtles (Dermochelys coriacea), and green turtles (Chelonia mydas). The nesting habitat within the RNVSGM encompasses 9.8 km of beach adjacent to the community of Gandoca and several smaller playitas between Gandoca and Manzanillo. The RNVSGM also harbours coral reefs and seagrass beds, which are popular feeding sites for hawksbills and greens of different life stages.

RNVSGM harbours the two small communities of Gandoca and Manzanillo.

The community of Gandoca is economically mainly dependent on the nearby banana plantations and subsistence farming, whereas Manzanillo is a small artisanal fishing community that in recent years has become a popular tourist destination.  However, some members of both communities are still poaching eggs and turtles to eat and sell, and turtles are killed accidentally in fishing gear. 

Historically, the small community of Gandoca is known for a successful community-centered sea turtle conservation project. From 1985 until 2011, a project that monitored sea turtle nesting activities was led by the Costa Rican NGO ANAI (later WIDECAST Costa Rica). However, due to a lack of funding and the conflict-prone nature of the adjacent community, the project was suspended and no active monitoring of sea turtle activity in RNVSGM happened for close to a decade. 


We run an independent environmental education and outreach program in the Southern Caribbean of Costa Rica. The program involves regular visits to local schools to increase awareness about the conservation status of sea turtles, the reasons why they are threatened, what everyone can do to help and why we shouldn't eat sea turtle eggs and meat.  We also regularly organize beach clean-ups to educate Costa Ricans about the detrimental effects of plastic pollution on marine wildlife, and have organized various workshops on diverse topics that affect sea turtles.

Additionally, we organize workshops for adults to teach the use of new communication technologies that can be used to promote and grow local businesses. 

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