The peak of Costa Rica’s sea turtle nesting season reached its highest point this weekend, as thousands of turtles arrived at Ostional Beach in the northwestern province of Guanacaste.

The phenomenon, known as an "arribada" (Spanish for arrival), brings hundreds of thousands of Kemp’s ridley sea turtles (Lepidochelys kempii) ashore to nest each year at the Ostional National Wildlife Refuge.

Park rangers estimate that while turtles arrive year-round, between 98,000 and 100,000 are expected from September through November, with October marking the height of the season.

Each Kemp’s ridley can grow up to 28 inches (70 centimeters) long and weigh about 220 pounds (100 kilograms).

A single turtle can lay between 80 and 120 eggs, but only about 1 percent survive natural predators and human interference.

Although the species is not currently endangered, it faces serious threats from indiscriminate fishing, ocean pollution, and egg poaching by people who consume or sell turtle eggs and meat.

The Ministry of Environment and Energy (MINAE) has implemented strict rules for visitors to the refuge, which was established in 1984 to protect nesting sites for Kemp’s ridley and other sea turtle species.

  

Visitor guidelines include:

• Tours must be booked through the Ostional Tourist Guides Association at (506) 6252-7412 or (506) 8447-0703.

• Entry is only permitted with a certified guide.

• Each turtle-watching group is limited to 10 people, including the guide.

• Visitors without authorized guides will be denied beach access.

• Flashlights, camera flashes, artificial lights, and cell phones are prohibited on the beach at night to prevent disorienting the turtles.

• Because the main road to the refuge passes through a forested area, access is restricted to four-wheel-drive or high-clearance vehicles.

The Ostional Wildlife Refuge not only safeguards nesting sea turtles but also provides habitat for marine invertebrates, amphibians, reptiles, mammals, and numerous bird species.

Four types of sea turtles nest at Ostional Beach:

• Hawksbill (Eretmochelys imbricata), which nests sporadically year-round.

• Green or black sea turtle (Chelonia mydas) nests in small numbers year-round.

• Leatherback (Dermochelys coriacea) nests from October to April.

• Kemp’s ridley (Lepidochelys kempii) nests in large numbers during both the rainy and dry seasons.

The Kemp’s ridley stands out as the only species that nests en masse during specific monthly periods, with as many as 200,000 turtles nesting both day and night between September and November.

It was the observation of this remarkable natural event that led to the creation of the Ostional National Wildlife Refuge in 1984.

   

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Have you visited the Ostional National Wildlife Refuge during peak nesting season? We would like to know your thoughts on this story. Send your comments to news@amcostarica.com