Practically seven lakh Olive ridley turtles laid eggs on the Rushikulya ‘rookery’ or nesting floor in Odisha’s Ganjam district throughout a mass nesting between February 16 and February 25. The event got here after the area didn’t witness any mass nesting final yr. In 2023, round 6.37 lakh Olive ridleys, an endangered marine species, laid eggs on the identical spot.
Olive ridley turtles (Lepidochelys olivacea) are the smallest and most considerable of all sea turtles on this planet. They get their identify from the olive inexperienced color of their heart-shaped shell, and inhabit heat waters of the Pacific, Atlantic, and Indian oceans.
Olive ridleys can develop about two ft in size, and 50 kg in weight. Scientists have no idea precisely how lengthy they reside, however like different sea turtles, Olive ridleys are doubtless long-lived — they attain maturity round 14 years of age.
In keeping with the Marine Turtle Specialist Group (MTSG) of the Worldwide Union for the Conservation of Nature (IUCN), there was a 50% discount in inhabitants dimension of those sea turtles because the Nineteen Sixties. The principle causes behind their decline embody long-term assortment of eggs and mass killing of grownup females on nesting seashores, and unintended seize in fishing gear which might result in drowning or trigger accidents that lead to demise.
These marine reptiles are finest recognized for his or her distinctive mass nesting — additionally known as arribada, Spanish for “arrival” — throughout which hundreds of females come collectively on the identical seashore to put eggs. “Arribada nesting is a behaviour discovered solely within the genus Lepidochelys which incorporates the Kemp’s ridley and olive ridley sea turtles. Though different turtles have been documented nesting in teams, no different turtles (marine or land) have been noticed nesting in such mass numbers and synchrony,” in response to a report on the US company Nationwide Oceanic and Atmospheric Administration’s (NOAA’s) web site.
Throughout nesting, greater than 600,000 females emerge from the waters, over a interval of 5 to seven days, to put eggs. They lay their eggs in conical nests which they dig with their hind flippers and are one and a half ft deep.
The place does arribada happen?
Whereas solitary nesting by Olive ridleys is thought to happen in roughly 40 international locations worldwide, arribada nesting happens on just a few seashores. The coast of Odisha (the place Rushikulya and Gahirmatha rookeries are located) is the biggest mass nesting web site for the Olive ridley, adopted by the coasts of Mexico and Costa Rica.
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Specialists say Rushikulya and Gahirmatha make for a perfect mass nesting web site on account of beneficial climate circumstances, heat sandy seashores, and an undisturbed coastal ecosystem.
Pratap Mohanty, previously with the division of marine sciences at Berhampur College (Odisha), instructed The Indian Specific that mass nesting principally happens to the north of the river mouth because the circumstances within the nearshore water and seashore sand are beneficial previous the nesting occasion and in the course of the nesting. He additionally mentioned turtles want to nest on a seashore with a gentle slope, medium width and better share of medium sand with low salinity.
“Decrease wind pace, low to reasonable waves and reasonable south-westward present earlier than nesting are useful for Olive ridley turtles to inhabit the coastal waters in giant numbers. Through the mass nesting, the enhancement in wind pace generates comparatively larger wave peak, serving to the ocean turtles to maneuver to the seashore for nesting simply,” he mentioned.
The coast in Odisha usually witnesses arribada within the first quarter of yearly.
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Why did Odisha see the arrival of so many Olive ridley turtles this yr?
In keeping with consultants, a variety of things may very well be answerable for numerous Olive ridleys arriving for nesting at Rushikulya this yr.
One may very well be beneficial climate circumstances. Sunny Khokhar, a divisional forest officer posted in Berhampur, instructed The Indian Specific that the shortage of rain in February might have contributed to this. Much less rain implies that there isn’t any erosion within the seashore, which, in flip, offers adequate house close to the river mouth for Olive ridleys to nest in giant numbers.
“The second purpose is the seashore gradient, the slope of a seashore from the highest to the water’s edge, which is much less this yr in comparison with earlier years,” Khokhar mentioned.
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Basudev Tripathy, a senior scientist of the Zoological Survey of India (ZSI), additionally echoed Khokhar’s level, saying that the Rushikulya seashore supplied sufficient house for numerous Olive ridleys to nest this yr. He mentioned that Gahirmatha may additionally witness mass nesting quickly.
Notably, Tripathy anticipated extra eggs to efficiently hatch this yr because the nesting had taken place in mid-February and never later. “The Olive ridley turtle eggs will hatch round 50 days from now. Which means fewer eggs will likely be misplaced on account of excessive temperatures and coastal erosion. The later the nesting takes place, extra eggs are misplaced to erosion which begins to change into a problem in April.”
Talking in regards to the absence of mass nesting in 2024, Tripathy mentioned it was but to be decided why precisely the arribada didn’t happen. “Mass nesting is a organic phenomenon, and a few years sea turtles skip nesting. We have no idea the precise purpose for this.”
