Olive Ridley Sea Turtle & Costa Rica

The olive ridley turtle is the second smallest sea turtle species and the most abundant. Its name is derived from the color of its shell, which resembles olive green. In Costa Rica, this species can only be observed on the Pacific Coast, where a unique phenomenon called “Arribadas” occurs. During an Arribada, hundreds of thousands of female olive ridleys gather on the same beach to lay their eggs. While the nesting cycle of each individual female lasts a couple of hours, during the arribadas, you will see thousands of turtles laying their eggs at the beach for over a week.

One such location where Arribadas occur is Playa Ostional, on the Pacific coast of Costa Rica. Here, a large number of olive ridleys gather during these mass nesting events, with thousands of turtles congregating at a single location over a short period. This typically coincides with changing moon phases.

Following the first day of nesting, the community at Playa Ostional harvests the eggs for consumption. This practice is allowed as it is believed to reduce the number of nests that later arrivals might otherwise destroy by digging up old nests. Ostional is the only community in Costa Rica with government permission to legally trade these eggs, which sometimes makes conservation efforts in the Caribbean more challenging. The lack of regulations on how those eggs are traded facilitates the commercialization of illegally harvested sea turtle eggs.

Scientific name

Lepidochelys olivacea

Common names

English: Olive Ridley

Spanish: Lora, cotorra.

Size and wight

Weight adult: Up to 50Kg (110 lbs), length adult: 74 – 80 cm (24-30 in).

Distribution

The olive ridley turtle has a widespread distribution throughout the tropical and subtropical waters of the Pacific, Atlantic, and Indian Oceans, primarily concentrated in the Indo-Pacific region. In the Pacific, sightings of this species have been documented from northern Mexico to Chile, encompassing central Pacific islands. In the Atlantic, olive ridleys have been reported from the Azores Islands in the North Atlantic to Uruguay. This broad distribution underscores the global presence of the olive ridley turtle across various oceanic regions.

Diet

The olive ridley turtle is an omnivorous species, which means it consumes a diverse range of food items. Its diet includes algae, lobster, crabs, tunicates, and mollusks. Olive ridleys exhibit impressive diving capabilities, reaching depths of up to 500 feet to forage on benthic invertebrates. They employ various feeding strategies, such as foraging in open waters off the coast, as well as showing a preference for areas with high levels of biological productivity, including the coast, continental shelf, and continental slope. This adaptability in feeding behavior allows olive ridleys to exploit a wide range of habitats and food sources.

Identifying features

Olive Ridley turtles exhibit a distinct olive/grayish green coloration and are characterized by a heart-shaped carapace. They typically possess 5 to 9 pairs of costal scutes along their shell. Each of their four flippers features one or two claws. Variations in size and form can be observed among olive ridleys across different populations worldwide.

Conservation status

The olive ridley turtle is recognized as one of the most plentiful among the seven sea turtle species. However, despite its abundance, the population has experienced a significant decline primarily due to overharvesting of their eggs during the 20th century and the hunting of females for their skin and flesh at nesting sites. As a result, the species is categorized as vulnerable on the IUCN Red List, and its trade is protected under CITES.

In addition to historical threats, the olive ridley faces contemporary challenges such as climate change, habitat loss leading to reduced nesting areas, and incidental capture in fishing gear (bycatch). These ongoing threats further exacerbate the vulnerability of olive ridley populations, emphasizing the urgent need for conservation efforts to ensure their long-term survival.