- At Rushikulya beach in Odisha, warming sands are producing more female hatchlings. Scientists warn that this may threaten long-term genetic health and mating success.
- Over half the current global sea turtle hotspots may disappear by 2050 as ocean warming forces turtles into new territories. India’s dense shipping corridors present escalating collision risks as turtles abandon traditional foraging grounds.
- Static models of sea turtle conservation may prove inadequate for climate-driven shifts. There is need for dynamic ocean management using real-time data, seasonal speed restrictions, and flexible protection plans for turtle populations.
Each winter, the beaches of Odisha witness one of nature’s most spectacular events. Hundreds of thousands of olive ridley turtles emerge from the Bay of Bengal for mass nesting, a phenomenon known as arribada. India’s conservation success in protecting these ancient mariners is remarkable. Yet beneath this achievement, climate change is quietly rewriting the rules of survival for these endangered species.
Two interconnected crises are now unfolding. On nesting beaches, warming sands are feminising entire generations of hatchlings. In the ocean, rising temperatures are forcing turtles to abandon traditional foraging grounds, pushing them into shipping lanes where vessel strikes loom as an escalating threat. Together, these pressures are fundamentally redefining what we mean by a sea turtle hotspot in the waters around India.
Temperature determines everything for sea turtle eggs buried in sand. Warmer nests produce female hatchlings and cooler ones yield males. This temperature-dependent sex determination has served sea turtles well for millions of years, but the balance is shifting. At Rushikulya beach in Odisha, data reveals olive ridley hatchlings are emerging predominantly female, with an average of 71% over the past nine years, and ratios reaching over 97% in some years, according to Monitoring Sea Turtles in India 2008-2024 report by Dakshin Foundation.
Danger of warming sands
In the short term, a female-biased ratio can actually help promote population growth, as more females mean more eggs. But this benefit comes with a heavy cost to genetic health. Graeme C. Hays of Deakin University, an expert in sea turtle biology, cautions that while a female bias helps in the short run, the long-term concern is inescapable. “In the long-term, there need to be enough adult males to ensure mating and clutch fertility,” Hays warned. “So, highly skewed hatchling sex ratios are a concern, and, at some point, there may need to be intervention to cool some clutches to produce more males.”
Beyond the skewed sex ratios, the rising sand temperature also carries a hidden mortality toll. High incubation temperatures increase hatchling mortality in nests, shows research by Hays. Moreover, the rising temperatures of both sand and air can lead to weaker hatchlings and increased embryonic death. Even if global temperatures stabilise, localised factors such as coastal development and heat-absorbing infrastructure can worsen the thermal stress on critical nesting grounds.
Ecologist Karthik Shanker, founder trustee of the Dakshin Foundation and lead author of the monitoring report, offers a measured assessment. “In the medium term, a female-biased sex ratio is better than a male-biased one. But this can have consequences for the genetic health of the population,” said Shanker. “I would not say that it is alarming at this stage, but it can be in some decades if temperatures continue to rise and turtles continue to nest at the same time of the year.”
Perilous migration
The crisis on land is mirrored by a perilous shift at sea. Ocean warming and acidification are disrupting the intricate marine food webs, causing a reduction in phytoplankton, which is the base of the ocean’s food chain, and degrading critical foraging habitats like coral reefs and seagrass beds. These changes are forcing sea turtles, highly migratory species that travel thousands of miles, to alter their foraging and migratory routes in search of cooler, more productive waters.
This climate-driven exodus is redefining the very concept of a sea turtle hotspot. Recent research in the peer-reviewed Science Advances journal projects an alarming outcome of over 50% of current global sea turtle hotspots ceasing to exist by 2050. For India, this means that the established and protected nesting beaches may lose their vital connectivity to viable foraging grounds.
For India, telemetry studies reveal leatherback turtles from the Andaman and Nicobar Islands undertaking extensive trans-Indian Ocean migrations, reaching as far as Madagascar and Western Australia. Green turtles in Lakshadweep are expanding into new areas, overgrazing seagrass meadows and creating unexpected ecological pressures.
As turtles are compelled to move, the new, climatically suitable habitats are increasingly projected to emerge in areas of high shipping intensity. This shift raises the risk of vessel strikes, one of the major sources of adult sea turtle mortality. India’s Exclusive Economic Zone is an area extending up to 200 nautical miles from its coastline that cover approximately 2.02 million sq. km. The zone’s dense shipping corridors connecting major ports presents a collision zone in the making.
“Rising temperatures, shifting currents, and changes in productivity and oxygen are driving the projected loss of more than half of sea turtle hotspots by 2050,” said Denis Fournier, research associate at the Université Libre de Bruxelles in Belgium and co-author of the Science Advances study. “As turtles move into cooler waters, many will overlap with major shipping routes, raising collision and bycatch risks, and threatening both turtle populations and the coastal ecosystems that depend on them.”
Complex policy challenges
Despite India’s strong commitment to conservation of sea turtles, from wildlife protection safeguards to making Turtle Excluder Devices (TEDs) in fishing nets mandatory in coastal seas where turtles are found, the pace and scale of climate change have exposed a flaw in traditional policy.
The policy challenge is immense, requiring complex, shifting climate science to be integrated into national conservation law and requiring cross-jurisdictional cooperation through agreements like the Indian Ocean – South-East Asian (IOSEA) Marine Turtle Memorandum of Understanding. “The real action is in the realm of climate policy and habitat protection,” Shanker pointed out. “Sea turtle population recover rapidly when nesting and foraging habitats are intact.”
Fournier maintained that static conservation alone would fail under climate change because the animals are already shifting into new, often high-risk, human-use areas. “The conservation community and national policymakers must prioritise anticipatory, dynamic measures like monitoring, flexible spatial protections, and regulation of shipping and fisheries that can be implemented rapidly where and when turtles appear,” he said. Protecting the process of movement, connectivity and low-mortality pathways, and not just a fixed place, is the right way to go, Fournier said.
International agreements could provide a framework to help drive sea turtle conservation measures, said Hays. “The global initiative for countries to designate 30% of their oceans as protected areas by 2030 can help sea turtles by providing safer areas for them with reduced threats,” he said.
India has a strong foundation for sea turtle conservation. All species found in seas around India are protected under Schedule I of the Wildlife (Protection) Act, 1972, the strongest safeguard the law offers. The mandatory use of TEDs in Odisha and Andhra Pradesh has reduced bycatch, and seasonal fishing bans offer temporary respite. But these measures were designed for a more stable world.
Path to resilience
India’s coastal communities have long revered sea turtles. In Andhra Pradesh’s Kurma Kulam caste and Odisha’s turtle worship rituals, cultural reverence has provided a protective buffer against exploitation. Yet tradition cannot cool warming sand or redirect shipping lanes.
The scale of the potential crisis demands a paradigm shift, from static, place-based conservation to adaptive, process-based protection, said Fournier. This means reimagining how and where we protect sea turtles. Dynamic ocean management offers one promising approach. Using real-time data from satellite telemetry and vessel tracking, managers can implement seasonal speed restrictions or temporary fishing closures in areas where turtles are known to aggregate. Such strategies are flexible and responsive and can be integrated with existing shipping and fisheries governance.
On land, interventions such as shaded nests or irrigation can help cool incubation temperatures and produce more males. “Simple, community-led interventions, like nest shading or controlled hatcheries, can have a meaningful impact,” said Hays. But these measures must be applied judiciously. “There is still a need for local information on hatchling sex ratios, the abundance of adult males, and when intervention to cool clutches is needed,” Hays added. However, Shanker is sceptical of such interventions to mass nesting sites such as those found on Odisha’s coast.
The olive ridley population at Rushikulya, a lineage dating back 3-4 million years, survived past ice ages and ocean upheavals. Its resilience across millennia contrasts starkly with the unprecedented pace of anthropogenic climate change. Perhaps the most critical step is protecting the ecological processes that enable sea turtles to adapt. “We must prioritise anticipatory, dynamic measures that can be implemented rapidly where and when turtles appear,” said Fournier. “Conservation can’t be anchored to fixed lines on a map. It must follow the animals.”
The survival of India’s sea turtles increasingly depends on aligning conservation with a changing planet. Integrating climate science into marine policy, operationalising regional cooperation, and embracing adaptive, dynamic protection are essential steps. Without them, India risks guarding beaches fewer turtles visit and waters they no longer frequent, while these ancient mariners find themselves stranded amid the shipping lanes of the Anthropocene.
Banner image: Warming sands lead to more female hatchlings which may have long-term effects on the population. Sea turtle nests are influenced by temperatures. Warmer nests produce female hatchlings, and cooler ones yield males. Image by Pawar Pooja via Wikimedia Commons (CC BY-SA 4.0).
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