Every year, sometime in the months of February and March, about a week after the new moon, something phenomenal occurs on the beaches of Rushikulya and Gahirmatha, Odisha.
Hundreds of thousands of turtles ascend on the beach, looking to meet old friends and lay their eggs. This is the very beach where they had emerged as hatchlings themselves, so this is, infact, a return of the olive ridleys. This is no ordinary social gathering – this unique mass nesting phenomenon is called arribada, from the Spanish, meaning “arrival”
Olive ridley turtles are the smallest of the marine turtlespecies in the world. The coast of Odisha in India is one of the world’s largest mass nesting site along with the coasts of Mexico and Costa Rica. It is often believed that potentially only one hatchling survives to reach adulthood for every 1000 hatchlings that enter the sea!
The olive ridleys arrive at the offshore waters of Odisha during the months of November and December during the breeding season and mate in the near-shore waters within five kilometres of the coastline.
Any time between the months of February and March female ridleys synchronously start coming ashore to lay their eggs over a period 3-10 days.
During an arribada, upto 50000 turtles can come ashore to nest in a single night - the largest ever nesting recorded at Rushikulya was over 400,000 turtles over a period of 6 nights in February 2017!
The turtles lay their eggs in flask shaped nests about a foot and a half deep, which they laboriously dig with their hind flippers. The eggs incubate under the sand for a period of 45-55 days depending on the weather conditions.
After the arribada, the females head back into the sea and typically migrate back to their foraging grounds.
After about 45-65 days, the eggs begin to hatch and these beaches are swamped with crawling olive ridley turtle babies, making their first trek towards the vast ocean.
Once near the surface, the hatchlings will wait until the temperature of the sand cools, usually indicating night time, when they are less likely to be eaten by predators or tire due to the heat. Hatchlings use the natural light horizon, which is usually over the ocean, along with the white crests of the waves to reach the water when they emerge from the nest. Other light sources such as beachfront lighting, street lights or headlights from vehicles can disorient them, causing thousands of hatchling deaths.
The fishermen community, along with WWF-India, has been involved in protecting the olive ridley hatchery at the mass nesting site at Rushikulya, in Odisha, by fencing off the nesting area and patrolling it till hatching and ensuring a safe passage for the hatchlings to the sea.
Though international trade in olive ridley turtles and their products is banned under CITES Appendix I, the most severe threat they face is the loss of nesting habitat due to large scale coastal development projects such as ports and harbour constructions.
Direct threats such as poaching of adults for meat, shell and leather as well as eggs have drastically reduced along the Indian coast thanks to widespread conservation education programmes that are conducted along the coast various conservation agencies. The accidental killing of adult turtles through entanglement in trawl and gill nets due to intensive fishing during their mating season around nesting beaches has also had a severe impact on most breeding populations.
WWF-India works with the local community and volunteers in Rushikulya by erecting Tuflex net fence (as protection from predators), patrolling beaches and recording data that will help in the conservation of this vulnerable species.
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