Climate change? Experts are not sure as Olive Ridley ‘Arribada’ starts a month early at Odisha’s Rushikulya

Officials and scientists are unsure as to what could have caused the start of the mass nesting or ‘Arribada’ of Olive Ridley turtles at the Rushikulya rookery in Odisha’s Ganjam district over a month ahead of last year’s nesting.

The mass nesting started early on the morning of February 23, 2023 and continued through the day to February 24. In 2022, a record 550,317 turtles nested at Rushikulya between March 27 and April 4, official sources said.

“It is a natural phenomenon. We can’t be sure of the exact cause,” Amlan Nayak, divisional forest officer (DFO), Berhampur forest division, told this reporter.

Experts said suitable climatic and beach conditions were some of the reasons for the early mass nesting of Olive Ridley turtles this year.

“The softness of the sand due to the dry weather and more space on the beach are some of the reasons for early mass nesting in the area than the previous year,” said Biswajit Mohanty, an environmentalist.

In previous years, the Arribada has usually taken place in the last week of February on Rushikulya beach as well as in the Gahirmatha Marine Sanctuary in Kendrapara district, said Mohanty. Rushikulya beach is considered as the second biggest rookery for the sea turtles in India after Gahirmatha.

Anjan Prusty, professor of environmental science, Berhampur University, said climate change might be the cause of the early nesting of the turtles. However, more detailed studies were needed to find out if there was a link, he added.

The nesting

On February 23, the first day of the mass nesting, over 0.180 million Olive Ridley turtles laid eggs on the four-km-long sandy beach from Podampeta to Bateshwar. On the second day, 0.138 million turtles laid eggs at the site.

The mass nesting continued during the day, the second occasion when this has happened at Rushikulya according to Nayak. The last time this had happened was in 2020.

Anil Mohapatra, a senior scientist and officer-in-charge of the Estuarine Biology Regional Centre (EBRC), part of the Zoological Survey India’s (ZSI) regional centre at Gopalpur-on-sea, said the mass nesting took place at the right time this year.

In previous years, the mass nesting had taken place late due to which several eggs were destroyed. “We hope more hatchlings come out this year due to the right time of mass nesting,” said Mohapatra.

Nayak said the mass nesting process is likely to take place for some more days. “We have divided the beach into 50 sectors and engaged over 200 forest staff and volunteers to protect the eggs. The entire site has been fenced off to prevent the entry of wild dogs, jackals and other predators,” he said.   

The forest officials cleaned the beach before the Arribada to facilitate the turtles’ smooth nesting. The Odisha government imposed a ban on fishing activities on the beach from November 1, 2022 to May 31, 2023.

The turtle eggs normally take 45 days to hatch. After this, tiny hatchlings come out and make their way to the sea, said Nayak.

ZSI scientists found that 55 adult female turtles (17 on February 23 and 38 on February 24) which were tagged by them in 2021 and 2022, have come again to the beach this year for nesting.

“The process of tagging and detection is going on at the mass nesting site,” said Mohapatra. 

On February 23, the scientists tagged 1,150 turtles. In the last two years, they had tagged around 8,500 turtles as part of the Olive Ridley turtle programme carried out jointly by the ZSI and state forest department to study the species’ nesting routes, according to Mohapatra.

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