The olive ridley sea turtle, Lepidochelys olivacea, is the smallest sea turtle, typically reaching a shell length of two to two and a half feet and weighing between 77 and 110 pounds. Although considered the most abundant globally, its population has declined significantly, leading to a conservation status of Vulnerable. As a highly migratory species, the olive ridley travels vast distances between feeding and nesting grounds.
Global Presence Across Ocean Basins
The olive ridley turtle inhabits tropical and subtropical waters across a circumglobal distribution, making it one of the most widely spread marine turtle species. They are found across the Pacific, Indian, and South Atlantic Oceans, ranging into both offshore, open-ocean areas and shallower, nearshore environments.
In the Pacific Ocean, their range extends broadly from Southern California down to Northern Chile in the Eastern Pacific. Indian Ocean populations are concentrated around the eastern coast of India and Sri Lanka, where they are seen in great abundance. In the Atlantic Ocean, ridley turtles are found in the southern portion, along the coasts of West Africa and the northern part of South America. They are largely absent from the North Atlantic, preferring warmer, equatorial currents for foraging and migration.
Critical Nesting Grounds and Arribada Sites
The most defining feature of the olive ridley’s distribution is the phenomenon known as Arribada, a Spanish term meaning “arrival.” This refers to a synchronized mass nesting event where thousands of females emerge simultaneously over a few days to lay eggs on the same stretch of sand. Only a handful of beaches globally host these mass nesting events.
In the Eastern Pacific, the most significant Arribada sites are along the coasts of Mexico and Central America. Playa Escobilla in Mexico hosts hundreds of thousands of nesting females during peak seasons. Further south, the beaches of Ostional and Nancite in Costa Rica are globally recognized for their massive, recurring nesting aggregations.
Along the coast of the Indian Ocean, the state of Odisha in India hosts the largest known nesting sites. Gahirmatha Beach, the mouth of the Devi River, and the Rushikulya rookery are the primary locations in Odisha where female olive ridleys congregate. These beaches see mass nesting events, with Gahirmatha alone recording over a hundred thousand nests in a single season.
Preferred Marine Environments
While famous for their appearances on sandy beaches, olive ridleys spend the majority of their lives at sea. They are found in the neritic zone, which includes the shallow waters over the continental shelf, often near coastal bays and estuaries. These inshore areas offer a rich environment that supports their omnivorous diet.
The turtles forage on a variety of prey, including shrimp, crabs, mollusks, and tunicates, often diving to depths of 500 feet to reach these bottom-dwelling invertebrates. This preference for benthic organisms means they seek out waters with soft, silty, or muddy bottoms where their prey can be found. During long-distance migrations, the turtles travel extensively through the deeper, open-ocean pelagic zone, maintaining a preference for warm, tropical and subtropical waters.