Olive Ridley Sea Turtle

The Olive Ridley is one of the smallest sea turtles in the world. Its scientific name is Lepidochelys olivacea, and it gets its common name from the olive-green colour of its shell. It lives in the warm waters of the Pacific, Indian and Atlantic Oceans. It is famous for one rare habit: thousands of females come ashore together on the same beach, over a few nights, to lay eggs. This mass nesting is called an arribada.

What does the turtle look like?

An adult is small for a sea turtle. Its shell (called the carapace) is usually about 60–75 cm long, and it weighs about 35–45 kg. The shell is heart-shaped and almost round. Like all sea turtles, it breathes air, so it must come to the surface to breathe. It eats jellyfish, shrimp, crabs, snails, fish and algae, so it is an omnivore (it eats both plants and animals).

What is an arribada?

"Arribada" is a Spanish word meaning "arrival". Instead of nesting alone, thousands or even lakhs of females arrive at one beach within a few days. Only one group of turtles, the genus Lepidochelys, does this. That group has two species: the Olive Ridley and the Kemp's Ridley. Scientists think nesting together is a safety-in-numbers trick: predators like dogs, jackals and birds cannot eat all the eggs, so many survive.

• The world's main arribada beaches are on the Pacific coast of Mexico and Costa Rica (for example, Ostional beach), and on the Odisha coast in India.
• In India, turtles nest here and there on both the east and west coasts. But mass nesting happens only in Odisha.

How does the life cycle work?

The turtles move through a fixed yearly pattern. In Odisha it goes like this:

1. Arrival and mating (around November): Large groups of turtles gather in the shallow sea near the nesting beaches and mate there.
2. Nesting (usually February to April): A female crawls up the beach at night, digs a pit in the sand with her back flippers, lays about 100 eggs, covers them and goes back to the sea.
3. Incubation (about 45–55 days): The eggs stay warm under the sand. No parent looks after them.
4. Hatching: Tiny hatchlings dig out and rush towards the sea, usually at night. They find the sea by moving towards the brighter horizon over the water.

The temperature of the sand decides whether a baby turtle becomes male or female. This is called temperature-dependent sex determination. Warmer sand gives more females; cooler sand gives more males. Studies at Gahirmatha found that sand above about 30°C produced almost only females. This is why climate change is a real worry for this species.

Very few hatchlings survive. Birds, crabs and fish eat many of them. Scientists commonly estimate that only about one in a thousand reaches adulthood [Unverified]. That is why every nest counts.

India's main nesting sites (all in Odisha)

• Gahirmatha beach (Kendrapara district): long described as one of the largest Olive Ridley nesting sites in the world. It lies inside the Gahirmatha Marine Sanctuary.
• Rushikulya river mouth (Ganjam district): in recent years this has often had the biggest numbers.
• Devi river mouth (Puri district): a smaller mass nesting site.

Odisha is estimated to host about half of the world's Olive Ridley population and about 90% of India's.

What is the Gahirmatha Marine Sanctuary?

The Odisha government declared it in 1997 under the Wildlife (Protection) Act, 1972. It covers about 1,435 sq km, almost all of it sea (about 1,408 sq km of water and 27 sq km of land). It sits next to the Bhitarkanika mangrove area. Bhitarkanika Wildlife Sanctuary lies on its landward side, and Bhitarkanika National Park (notified in 1998, about 145 sq km) is close by.

In 2023, the forest department placed buoys in the sea to mark the sanctuary's boundary clearly, so fishers know where they cannot go.

How is the turtle protected by law?

The protection comes in layers: international, national and state.

• IUCN Red List: Vulnerable. This means it faces a high risk of dying out in the wild if threats continue.
• CITES: listed in Appendix I. This means international trade in the turtle or its parts (shell, meat, eggs) for commercial purposes is banned.
• Convention on Migratory Species (CMS): sea turtles travel across many countries' waters, so they are covered under this treaty. India is a signatory to the CMS's Indian Ocean–South-East Asia (IOSEA) Marine Turtle MoU, a non-binding agreement for turtle protection in the region.
• Wildlife (Protection) Act, 1972: all five sea turtle species found in India, including the Olive Ridley, are in Schedule I. Schedule I gives the highest level of protection, the same as the tiger. Hunting or trading it can lead to jail.
• Wildlife (Protection) Amendment Act, 2022: this law did not change the turtle's schedule. It gave the Coast Guard powers to enter, search and detain vessels for wildlife crimes at sea, including those involving marine turtles.
• Orissa Marine Fishing Regulation Act, 1982: a state law that lets Odisha close areas of sea to fishing. Under it, the state bans fishing within 20 km of the coast near Gahirmatha and the Devi and Rushikulya river mouths during the turtle season.

How does enforcement work on the ground?

Several agencies work together each season.

• The forest department runs the fishing ban, patrol boats and protection camps on the beaches and islands.
• The Indian Coast Guard runs Operation Olivia every year during the breeding season (roughly November to May). It uses ships and aircraft to catch trawlers fishing illegally in the closed zones.
• Marine police stations along the coast help stop illegal boats.
• Volunteers and local communities, especially at Rushikulya, guard nests, fence nesting areas and help hatchlings reach the sea.

Why do the turtles need protection? The main threats

• Trawler nets (bycatch): This is the biggest threat. Turtles get trapped in fishing nets, cannot come up to breathe, and drown. Every year many dead turtles wash up on Odisha's beaches.
• Loss and erosion of nesting beaches: Sea erosion, ports and construction shrink the sandy beaches. Gahirmatha's nesting island has been badly eroded in some years.
• Light pollution: Bright lights near beaches confuse hatchlings. They crawl towards the lights on land instead of the sea and die.
• Predators and egg theft: Stray dogs, jackals and people dig up nests.
• Climate change: Hotter sand produces too many females. Rising seas and storms also wash away nests.

Why does mass nesting sometimes not happen?

In some years, no arribada takes place on a beach at all. At Gahirmatha this happened in years such as 1982, 1988, 1997 and 2002, and the whole Odisha coast saw no arribada in 2026. Forest officials explain that this is usually a natural event, not proof that the population is falling. Untimely rain, eroded beaches and very high tides near full moon and new moon can stop turtles from coming ashore. Such turtles may nest later or elsewhere.

Commonly confused concepts

• Olive Ridley vs Leatherback: The Olive Ridley is one of the smallest sea turtles and nests in huge groups (arribada). The Leatherback is the largest sea turtle. It has no hard shell (its back is leathery skin) and nests alone, for example on the Andaman and Nicobar Islands. Its IUCN status is also Vulnerable at the global level.
• Arribada vs solitary nesting: In an arribada, thousands nest together over a few nights. In solitary nesting, females come ashore one by one through the season. Olive Ridleys can do both.
• Marine Sanctuary vs National Park: Both are protected areas under the Wildlife (Protection) Act, 1972. A sanctuary allows some regulated human activity. A national park has stricter rules, and people cannot hold rights such as grazing inside it. Gahirmatha is a sanctuary; Bhitarkanika has both a national park and a sanctuary.
• Gahirmatha vs Rushikulya: Gahirmatha is in Kendrapara district, inside a marine sanctuary and close to the Bhitarkanika mangroves. Rushikulya is in Ganjam district, further south, near the Rushikulya river mouth.

Issues, criticism and the way forward

• Fishers' livelihoods: A seven-month ban hits small fishing families hard. Many say the compensation or alternative income given to them is too small or comes late. Without their support, illegal fishing continues.
• Weak enforcement: The sea area is big and patrol boats are few. Trawlers from other states sometimes enter the closed zones.
• Dead turtles every year: Hundreds of turtles still wash up dead each season, which shows bycatch remains high.
• Way forward: Experts suggest using Turtle Excluder Devices in all trawlers, paying fair and timely compensation, involving fishing communities as turtle guards, controlling lights near nesting beaches, and protecting beaches from erosion. Long-term scientific monitoring, including tagging turtles, helps track population changes.

Concepts to Know

• Carapace: The upper, hard part of a turtle's shell.
• Bycatch: Animals caught in a fishing net by accident, when fishers were trying to catch something else. For example, turtles caught in a net meant for shrimp.
• Trawler: A fishing boat that drags a large cone-shaped net (a trawl net) through the water or along the sea floor.
• IUCN Red List: A global list, run by the International Union for Conservation of Nature, that grades how close each species is to dying out (for example: Least Concern, Vulnerable, Endangered, Critically Endangered).
• CITES: The Convention on International Trade in Endangered Species of Wild Fauna and Flora. It controls trade in wild animals and plants between countries. Appendix I species cannot be traded commercially.
• Rookery: A place where many animals gather to breed or nest.
• Hatchling: A baby animal that has just come out of its egg.