Olive Ridley Sea Turtles

Context:

Pairs of Olive Ridley Sea turtles have begun emerging on the sea waters off Gahirmatha Marine Sanctuary along the Odisha coast, marking the commencement of the annual mass nesting of these endangered marine species.

Relevance:

Prelims, GS-III: Environment and Ecology

Dimensions of the Article:

1. Olive Ridley Sea Turtle
2. Breeding Grounds of the Olive Ridley Sea Turtle in India
3. Threats to the Olive Ridley Sea Turtle
4. Turtles and Turtle conservation in India

Olive Ridley Sea Turtle

• The olive ridley sea turtle (Lepidochelys olivacea), also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae.
• The species is the second smallest and most abundant of all sea turtles found in the world.
• This turtle and the related Kemps ridley turtle are best known for their unique mass nesting called arribada, where thousands of females come together on the same beach to lay eggs.
• The species is listed as Vulnerable in the IUCN Red List, Appendix 1 in CITES, and Schedule 1 in Wildlife Protection Act, 1972.
• Olive-ridleys face serious threats across their migratory route, habitat and nesting beaches, due to human activities such as unfriendly turtle fishing practices, development, and exploitation of nesting beaches for ports, and tourist centres.

Breeding Grounds of the Olive Ridley Sea Turtle in India

• The Gahirmatha Beach in Kendrapara district of Odisha (India), which is now a part of the Bhitarkanika Wildlife Sanctuary, is the largest breeding ground for these turtles.
• The Gahirmatha Marine Wildlife Sanctuary, which bounds the Bhitarkanika Wildlife Sanctuary to the east, was created in September 1997, and encompasses Gahirmatha Beach and an adjacent portion of the Bay of Bengal.
• Bhitarkanika mangroves were designated a Ramsar Wetland of International Importance in 2002. It is the world’s largest known rookery of olive ridley sea turtles.
• Apart from Gahirmatha rookery, two other mass nesting beaches have been located, which are on the mouth of rivers Rushikulya and Devi.
• The spectacular site of mass congregation of olive ridley sea turtles for mating and nesting enthralls both the scientists and the nature lovers throughout the world.

Threats to the Olive Ridley Sea Turtle

• Known predators of olive ridley eggs include raccoons, coyotes, feral dogs and pigs, opossums, coatimundi, caimans, ghost crabs, and the sunbeam snake.
• Hatchlings are preyed upon as they travel across the beach to the water by vultures, frigate birds, crabs, raccoons, coyotes, iguanas, and snakes. In the water, hatchling predators most likely include oceanic fishes, sharks, and crocodiles.
• Adults have relatively few known predators, other than sharks, and killer whales are responsible for occasional attacks. On land, nesting females may be attacked by jaguars. Notably, the jaguar is the only cat with a strong enough bite to penetrate a sea turtle’s shell, thought to be an evolutionary adaption from the Holocene extinction event.
• In recent years, increased predation on turtles by jaguars has been noted, perhaps due to habitat loss and fewer alternative food sources. Sea turtles are comparatively defenseless in this situation, as they cannot pull their heads into their shells like freshwater and terrestrial turtles.
• Humans are still listed as the leading threat to L. olivacea, responsible for unsustainable egg collection, slaughtering nesting females on the beach, and direct harvesting adults at sea for commercial sale of both the meat and hides.

Turtles and Turtle conservation in India

• There are five turtle species in Indian waters — Leatherback, Loggerhead, Hawksbill, Green and Olive Ridley.
• In India sea turtles are protected under the Indian Wildlife Protection Act of 1972, under the Schedule I Part II.
• Every year, thousands of sea turtles are accidentally captured, injured or killed by mechanised boats, trawl nets and gill nets operated and used by comercial fishermen.
• The turtle breeding season is usually between November and December. In Tamil Nadu, for example, the Olive Ridley nests between December and April along the Chennai-Kancheepuram coastline.
• Sea turtles, especially the leatherback, keep jellyfish under control, thereby helping to maintain healthy fish stocks in the oceans.
• The Green turtle feeds on sea grass beds and by cropping the grass provide a nursery for numerous species of fish, shellfish and crustaceans.

-Source: The Hindu