TREE Foundation
After swimming thousands and thousands of miles in the magical oceans, the Olive Ridley turtles, not all but some, arrive on the city shores every year to nest. These sea turtles invoke no less fascination in Tamil Nadu than in Odisha, where they mass-nest, famously referred to as arribada, a spectacle that enthrals wildlife enthusiasts.
In the ever-expanding metropolis of Chennai, solitary female Olive Ridleys arrive in the stormy or starlit nights by the end of winter monsoons on the same stretch of the coast, where they were born, to nest in peace. Each turtle lays around 50 to 150 eggs, which take nearly two months to hatch. By the beginning of summer, the tiny Ridleys waddle through the warm sands into the blue bay to begin a life unpredictable in the oceans. Over the years, the Tamil Nadu government’s efforts at conserving sea turtles have strengthened, along with the active support of non-governmental organisations. However, while the effect of ocean warming, brought on by climate change, is threatening the turtle population by skewing the gender ratio, anthropogenic factors and poor enforcement of regulations continue to have a negative impact on Olive Ridleys, which are listed in Schedule I of the Wildlife (Protection) Act, 1972, and as ‘vulnerable’ by the International Union for Conservation of Nature.
Trapped in nets
One of the primary threats to Olive Ridleys is fishing gear, especially ‘ghost’ nets. Owing to the high cost of nets, fishermen use them for many years. Ideally, the nets should be replaced every three to five years. Because of the wear and tear, the nets get disconnected in sea and end up becoming ghost nets. As sea mammals need to swim up for breathing regularly — 45 minutes in the case of Olive Ridleys — they get entangled in the ghost nets, leading to drowning. “When we did the dugong recovery programmes in two States and a Union Territory [Gujarat and Tamil Nadu, and Andaman and Nicobar Islands], we realised that ghost nets were one of the most important problems for dugongs, especially in Gujarat and Tamil Nadu,” says K. Sivakumar, Department of Ecology and Environmental Sciences, School of Life Sciences, Pondicherry University.
A former scientist at the Wildlife Institute of India, Mr. Sivakumar worked on the National Marine Turtle Action Plan, which was launched by the Ministry of Environment, Forest and Climate Change in 2021. “In fact, it is a big problem for the fishers too. Nets get entangled in ghost nets. Or they lose their catch sometimes. It is a problem not only for the wildlife but also for fishermen,” he says, suggesting that the States subsidise the timely replacement of fishing nets.
Supraja Dharini, founder and chairperson, TREE Foundation, a non-governmental organisation working in marine conservation, says her team has observed around 165 turtles wash ashore dead so far this nesting season. The Foundation works with the Forest Department and fishermen of Neelankarai in Chennai district and Alamparai in Chengalpattu. At a workshop conducted by Ms. Dharini’s team at the Thazhuthali Kuppam estuary in Chengalpattu last week to demonstrate the right methods to remove sea turtles, whales, and sharks from fishing nets, it was said fishermen of Chinnakuppam, a hamlet in the Kadalur panchayat, came across nine Olive Ridley turtles entangled in a ghost net on February 6 and freed them in the sea.
The ghost nets apart, the nets set for ray fish and squid, called thirukka valai and kadamba valai respectively in the northern Tamil Nadu coast, pose a major threat to the sea turtles. “From the information we have got from fishermen along the coast from Neelankarai to Alamparai, a few of the villagers have set nets for ray fish, and a lot of turtles have been dying here. We have also heard that a net for squid is trapping a lot of turtles because it is set parallel to the beach from the evening to the next morning, when the turtles come ashore for nesting,” she explains. In a letter to officials of the Department of Fisheries, Ms. Dharini has requested that the ban on ray fish and squid nets during the turtle nesting season be enforced strictly. “They can ask fishermen to hand the nets over to the department till the month of April,” she suggests.
Letting turtles escape
In areas where trawlers are used for commercial fishing, it is recommended that the nets be fitted with the Turtle Excluder Device (TED) to help turtles escape. TEDs have helped to reduce mortality in Odisha where they are mandatory, says Mr. Sivakumar. “Fishermen say that when they use the TEDs, they lose catch. Of course, there is a 5%-8% of catch loss and that is a substantial loss for the fishermen. It needs to be compensated by the government by [giving] a discount on diesel or something else, he adds. For fishermen like Selvam of Cuddalore, who fishes on trawlers, turtles are akin to God. “Most of our fishing nets have TEDs and if we get a turtle on board by chance, we let it go back to the sea with a prayer and after lighting a piece of camphor or an agarbatti. We never harm turtles,” he says.
Jothi, a net-maker who trims, cuts, and mends the nets to suit the needs of around 600 boats at the Kasimedu fishing harbour in Chennai, says all the boats he handles have TEDs. “After the COVID-19 pandemic, we have been given a new design of TED. The size of the gaps in the net at the bottom corner has been increased from 18 mm to 45 mm, allowing the turtles more freedom. Though fishermen end up losing a portion of their catch by using TEDs, they do not mind it since they do not want to harm the turtles,” he explains.
Sources in the Department of Fisheries say that after the trial of the new TED by the Central Institute of Fisheries Technology (CIFT), Kochi, scientists have concluded that it is better than the previous one. The M.S. Swaminathan Research Foundation (MSSRF) has been organising trials, awareness programmes, and training modules on the modified TED, along with the CIFT. “We have been working consistently with the fishing community on various issues. The TED design has been modified by the CIFT. The new design was developed on the basis of the recommendations of the National Oceanic and Atmospheric Administration, the U.S., and the Marine Products Export Development Authority (MPEDA), besides the needs of the Indian trawling sector,” says S. Velvizhi, head of Fish For All Centre, MSSRF.
According to some, mortality of around 10% of the turtles coming ashore to nest is normal. However, it is important to note that a very small percentage of hatchlings, released into the sea, survive in the first place; so, every death counts. “Scientifically, we do not have any documentation on what percentage of mortality is ‘normal’. But what we know, from our work on the Odisha coast for almost two decades, is that in the early days before taking any action [for conservation], we used to lose about 80,000 to 1.5 lakh turtles every year (out of over 6 lakh turtles) during mass-nesting because of fisheries interference. But recently the number has dropped vastly, to below 1,000,” points out Mr. Sivakumar. He attributes the reduction in deaths to TEDs. Policy change, awareness, and enforcement are essential for controlling mortality due to fishing gear, he adds.
Coastal pollution
Debris and light and noise pollution pose a threat to Olive Ridleys. Plastic waste continues to be abundant on beaches. The threats to sea turtles in the Tamil Nadu coast, as listed in the National Marine Turtle Action Plan, include nest predation, plastic and light pollution, and habitat degradation. Notably, the southern Chennai and Puducherry coasts are dotted with resorts, many of which are bulk waste generators.
While one part of the threats from plastic is the ingestion of polythene covers and fragments of fishing nets, according to recent studies, such as the one in Frontiers in Marine Science, it is said high concentrations of microplastics in sand could be an issue for marine turtles as any change in sand temperature may affect the sex ratio of hatchlings or alter the nest productivity.
Artificial lights can misdirect turtles going seawards after nesting and disorient hatchlings, both of which have an innate ability to find their way to the sea using the reflection of the moon and the stars on the water. The lights disrupt nest site selection and cause abandonment of nesting. A report from the Wildlife Institute of India notes that increasing thrust on coastal development is likely to drive up hatchling mortality due to light pollution. “Many resorts along the shore should not be there in the first place. But our Coastal Regulation Zone [policy] is often amended. It is one of the most amended policies in the country. Not only waste but also light and footprints on the beaches are not conducive to nesting of sea turtles,” says Mr. Sivakumar.
The tourist season, unfortunately, coincides with the turtle nesting season, says Zai Whitaker, founder of the Madras Crocodile Bank Trust (MCBT), Vada Nemmeli. “We have had people who come for projects here, staying at a close-by resort. They left because they could not sleep. Because the focus is now on loud music and harsh lights, hotels look more like mandapams,” she says. Sound from woofer speakers at nearby resorts and halls are heard at the MCBT, which, given its greenery, is also a nesting site for birds, she adds.
Police officers of the Kanathur station, told The Hindu that they would receive complaints about loud music through the helpline number 100 — although not regularly — during weddings, holiday season, or weekends. As the first step towards controlling the noise and light pollution along the coast, Ms. Whitaker suggests that the Forest Department hold a mandatory workshop for representatives of resorts, non-governmental organisations, fisherfolk, and village panchayats to discuss measures to have dim lights and control loud music.
(With inputs from Deepa H. Ramakrishnan.)
