6 lakh Olive ridley turtles return to Odisha's beaches to lay eggs
With the arrival of more than six lakh endangered Olive Ridley sea turtles, the serene and idyllic Gahirmatha beach in Odisha’s Kendrapara district has re-established itself as the world’s largest known rookery of these marine animals.
The delicate marine species which have dug out neat pits on the sandy beach have so far laid over whopping seven crore eggs. However, space constraints on the nesting beach has led to the damage of eggs with the marine animals re-digging the pits where nests had been erected earlier, a forest official said.
Since the commencement of mass-nesting otherwise described as ‘arribada’ (a Spanish term used for en masse laying eggs by turtle species) on February 22, the third highest ever congregation of marine species has taken place in the idyllic unmanned island with 6,01,641 turtles turning up for nesting, the official said.
The highest record of mass nesting was registered in 2001 with 7,41,000 turtles while the second best was 7,11,000 turtles in 2000. This year the spectacular natural phenomenon is still continuing since the past one week and is expected to last for at least three to four days, they said.
“It will be no surprise if the mass nesting record of past years is bettered this time,” said Subrat Patra, forest range officer, Gahirmatha marine sanctuary.
It’s only the female turtles that virtually invade the nesting beaches usually at the dead of night for laying eggs. After indulgence in instinctive egg-laying, the turtles leave the nesting ground to stride into the deep sea water.
Hatchlings emerge from these eggs after 45-60 days. It is a rare natural phenomenon where the babies grow without their mothers by their sides, the official said.
While six lakh turtles have laid over seven crore eggs, nearly 1.5 crore eggs were smashed by nesting turtles who loitered around the beach to find a congenial location to dig pit and lay eggs. The breeding turtles little knowing the existence of nests were sighted digging up the spot dismantling the already existing nests and eggs.
The one-km-long nesting ground has inadequate space to accommodate six lakh marine visitors. Therefore, it’s not humanly possible to stop the destruction of eggs, he said.
Each olive species lays about 80 to 120 eggs in pits they dig up for the purpose. They climb the shore after sunset and vanish into the sea before sunrise after laying eggs.
However, the rate of mortality of these endangered species is quite high. As hatching requires 45 to 60 days, many get destroyed, the official said. Besides, eggs are also washed away by sea waves during high tide. The eggs are incubated in the nest and grow, sans mother, to emerge as hatchlings. The hatchlings after breaking open from eggshells then enter the sea. It takes nearly 25 years for a turtle to attain adulthood and be able to mate and lay eggs, said Patra.
Endangered Olive Ridley sea turtles, which were tagged for the purpose of studying their migration pattern, have reappeared for mass nesting on the sandy Gahirmatha beach in Odisha.
The sighting of 'tagged' turtles on February 22 night, the day mass nesting of Olive Ridley turtles started this year, established the belief that these marine creatures prefer Odisha for laying eggs.
Forest Range Officer, Gahirmatha Forest Range, Subrat Patra, who was on duty at the beach and was a witness to this unique phenomenon said, ten female turtles with metallic tags fitted on their flippers were sighted on the beach during mass nesting.
The figure of the tagged turtles could have been higher since locating them amid millions of turtles in the darkness of the night was a Herculean task, he said.
The reappearance of tagged turtles in Gahirmatha provides evidence to the fact that the female turtles return to the same beach annually for laying their eggs, where they were born decades ago, Patra said.
There is every possibility of more tagged turtles turning up to lay eggs, he added.
The state forest department and Wildlife Institute of India (WII) over the years had tagged around 30,000 turtles with metallic labels to keep a tab on their pre and post-breeding migration, during arrival of these turtles for mass nesting.
The tagged turtles were spotted re-emerging at the nesting beaches of Gahirmatha, Devi river mouth and Rushikulya river mouth off Odisha coast.
Meanwhile, mass nesting of these delicate reptiles, which commenced a few days back on February 22 night, is in full swing.
Around 3,35,099 turtles have already laid eggs on the Gahiramatha Beach, world's largest rookery of sea turtles since February 22 night, said the Gahirmatha Forest Range Officer.
"We are hopeful of convergence of more turtles on the Gahirmatha Beach for mass nesting as a large congregation of turtles are still being sighted in mid sea," he said.
The number of turtles arriving at the odisha coast was much lower last year.
Before the tagging was undertaken, little was known regarding movement of these animals, said Divisional Forest Officer, Rajnagar Mangrove (wildlife) Forest Division, Bimal Prasanna Acharya.
Wildlife Institute of India in a joint endeavour with forest department in past years had tagged over 25,000 female turtles.
Tagging is most often conducted to obtain information on reproductive biology, movements and growth rates.
The tagging helps in studying the turtle's migratory route and areas of foraging, said forest officials.
Sea turtles throughout the world are known to migrate thousands of kilometers between their nesting beaches and feeding grounds.
Apart from tagging turtles to study their itinerant behaviour, Wildlife Institute of India (WII) in 2007 had experimented by fitting four turtles with Platform Transmitter Terminals (PTTs) with online monitoring of migratory routes.
The PTT fitted turtles were found to have migrated south towards Sri Lanka. However, the experiment had failed as four PTT-fitted turtles had stopped transmitting within two to four months, either due to some technical problems or mortality, said forest officials.