Turtles are masters of navigation. They live their entire
lives in the sea, coming ashore once in two or three years, and then only at
night for two or three hours to nest. Then the hatchlings emerge, tiny
creatures half the size of your palm, and venture into the ocean. Years later,
they come back to their birth shore to nest.
The enigma surrounding the lives of turtles appealed to Kartik Shanker. As a student in Madras Christian College in late 1980s, he and his friends participated in turtle conservation, a regular feature on Chennai beaches by conservationists, NGOs and the forest department since the Seventies.
In 1988, though, the forest department decided to close all hatcheries. Then this bunch of college students had the “crazy idea” of hatcheries on the city’s coastline. Later on, Shanker worked on small mammal community ecology in the upper Nilgiris for his PhD and on sea turtle genetics at the Wildlife Institute of India, Dehradun, for his post-doctoral research.
A regular participant at the annual symposium on sea turtle biology and conservation, he became president of the International Sea Turtle Society in 2009, and conducted the conference in Goa in 2010. There are only seven sea turtle species, but the conferences attract various species of people—scientists, biologists, NGOs, activists, conservationists, volunteers and turtle enthusiasts.
Now, an associate professor at the Centre for Ecological Sciences, Indian Institute of Science, Shanker’s lab work was on community ecology, the large scale patterns of distribution and diversity among plants and animals, especially frogs, lizards, and snakes, and reef fish, and on tracing the evolutionary history of these species, which is called biogeography. His lab also works on mixed species feeding groups where different species group together to feed—his lab may be the only one that works on this phenomenon in both birds and fish.
In addition, Shanker has authored two picture books for children, Turtle Story and The Adventures of Philautus Frog and a novel Lori’s Magical Mystery has just been published by Penguin, its theme informed by observations on mixed groups when he worked on the Great Nicobar Island back in 2001.
Shanker is also director of the Ashoka Trust for Research in Ecology and the Environment, Bengaluru. He is a founding trustee of Dakshin Foundation, and editor of Current Conservation. His book From Soup to Superstar: The Story of Sea Turtles along the Indian Coast obviously focuses on his great obsession.
Edited excerpts from a conversation with Fountain ink.
When did you see your first turtle, how did it feel then?
How does it feel now?
I saw my first Olive Ridley on Besant Nagar beach in Chennai
in the late 1980s. We had just started the Students Sea Turtle Conservation
Network and were on one of our first walks of the season. It was probably just
past 10 p.m. and the moon was up. I had gone on several turtle walks the
previous season but had only seen tracks, no turtles. So I still remember
feeling that thrill when we saw the track leading up the beach and no track
leading down, which meant the turtle was still nesting. We crawled up carefully
behind her and watched the whole process of nesting. I’ve seen thousands of
turtles nesting since then, but you never forget the first one.
Speaking of thousands, it’s an entirely different experience when you see your first mass nesting or arribada of Olive Ridleys. I was working on sea turtle genetics with the Wildlife Institute, and was in Odisha for field work. When the arribada (arrival in Spanish) started in Gahirmatha, I was at a different beach and it took nearly 24 hours non-stop travel by jeep and boat to get to Gahirmatha. Our camp was a small offshore island, and we went by fishing boat to the nesting beach, another small island a short distance away. When we reached the beach, there were thousands, perhaps tens of thousands of turtles in various stages of nesting. Sand flying everywhere, sometimes eggs being flung around when one turtle digs into the nest of another, it seems like absolute chaos. It’s truly one of nature’s most extraordinary spectacles.
How long they have been coming here, Odisha, and in which
months? Why those months? Could you talk about the tale of their coming here,
staying here, and going back into the ocean?
While the mass nesting of Olive Ridleys has been known to
science since the early 1970s, they were obviously known to communities much
earlier. In fact, a British ship’s captain records the coast of Balasore
(northern Odisha) having a “prodigious number of sea tortoises” during his
travels in the early 1700s.
Olive Ridleys arrive along the coast of Odisha around November and December. They mate in offshore waters and nest from about December to April. The arribadas usually happen in February or March. Once nesting is complete, they return to their feeding grounds, in the Bay of Bengal and off the coasts of southern Tamil Nadu and Sri Lanka.
Laying eggs, hatching, and so on... could you explain the
time it takes for all these things?
Like other turtles, Olive Ridleys nest at night. They come
ashore, crawl above the high tide line and dig a small flask shaped nest with
their hind flippers. They lay about 100–150 eggs, the nests incubate for about
45–50 days and sex is determined by temperature (lower temperatures produce
males). Once they emerge, the hatchlings immediately enter the sea, which they
find using the reflection of moonlight or starlight on water. They then drift
with currents for many years before they become adults. Sea turtles are also
able to sense the earth’s magnetic field which they use for navigation.
Could you talk about species, the ones we get here and
the others as well?
There are seven species of sea turtles in the world. Five
species—leatherback, green, hawskbill, loggerhead and Olive Ridley—are found
globally, and all occur in India. The Kemps Ridley is found in the Atlantic and
nests only on the east coast of Mexico, and the flatback is found only in
Australia. Olive Ridleys nest on both coasts of mainland India as well as in
the island groups. India’s best nesting beaches for leatherbacks and hawksbills
are in the Andaman and Nicobar Islands. Green turtles nest in Gujarat, Andamans
Olive Ridleys—their characteristics, unique features,
their weight, length, and their lives, anything that you personally found
touching or scientifically intriguing.
They are the smallest of sea turtles, unique in their mass nesting behaviour. Scientists have speculated that they do this so that the hatchlings can escape predation. When millions of hatchlings emerge together, then a fair number are going to escape predators on land and at sea. It’s called ‘predator satiation’.
Do their numbers vary and why? Any census?
There are not particularly good records of nesting in
Gahirmatha, though monitoring began in the 1970s. In a paper we wrote about 15
years ago, we found adult sizes were decreasing and we speculated that the
population may be declining. However, we have now been monitoring nesting at
Rushikulya for the last 10 years, and we have had some of the largest arribadas
there in the last four or five years, with about 200,000 or more turtles in
each arribada. Similarly, data from about 30 years from the students’ group in
Chennai seems to indicate that the population is stable or increasing.
Actually, population trends are hard to discern for sea turtles because of the inherent variation in nesting. Sometimes, numbers just fluctuate madly from one year to the next, and when they go down, everyone—the media, conservationists, government—gets upset and starts worrying. But there is a lot of year-to-year fluctuation, so only really long term studies can tell us what’s going on.
Turtles have to live long enough—until their teens—to lay
eggs. How many make it to that stage? Could you talk about their
survival and survival rates, both In India and in other parts of the world?
Olive Ridleys probably mature at 10 to 15 years, while green turtles could take 30 years or longer. It has been speculated that only 1 in 1,000 hatchlings makes it to adulthood, but there are not enough studies about survival rates.
Do we have any specific programmes that help turtles;
NGOs working for their survival and rehabilitation and moving them away from
There have been conservation groups for sea turtles since
the 1970s, when Rom Whitaker, Satish Bhaskar and others started turtle walks in
Chennai. While SSTCN is one of the longest running volunteer groups in India
(and probably the world), there are now NGOs in every single coastal state that
monitor turtles, protect their nests and carry out various outreach programmes.
Turtles nest on the Arabian Sea coast and the Bay of
Bengal. Please talk about their habitats, the miles they travel, their nests,
the temperature they prefer, the food they eat, and so on.
Olive Ridleys nest on both coasts, but their numbers are
much higher on the east coast with, of course, arribadas occurring in Odisha.
Very little is known about the populations in the Arabian Sea. As hatchlings,
most species are carried around by trans-oceanic currents, some of which go
around the entire Atlantic or Pacific. At this stage, they are omnivorous. As adults,
they become specialised in diet and habitat. Leatherbacks eat mostly jellyfish
and foray into very cold temperate waters and dive hundreds of metres in search
of food. Green turtles become totally herbivorous and feed on sea grass and
algae. The sea grass meadows of the Lakshadweep Islands provide excellent
feeding for greens. Hawksbills eat sponges, and loggerheads and Ridleys feed on
fish and crabs. Ridleys are known to feed on flying fish along the coast of Sri
Could you tell the tale of their migration?
Most sea turtles migrate thousands of kilometres between
feeding and breeding grounds. Loggerheads feeding along the coast of Baja
California migrate all the way across the Pacific to nest in Japan. Green
turtles feeding off the coast of Brazil migrate to the Atlantic and find
Ascension Island, a speck in the middle of the ocean.
We tracked 10 leatherbacks from Andaman and Nicobar. The first seven or eight went east along the coast of Sumatra, some reaching the west coast of Australia. We were then pretty sure that leatherbacks from this region had feeding grounds in the eastern Indian Ocean. But the last two ruined that theory. They went west and reached Mozambique and Madagascar, along the east coast of Africa.
Turtles have that evolutionary élan. They have been here
long before dinosaurs, before all of us, and may live long after we’re gone for
good. They have been part of so much of earth’s history. Could you talk about
their evolutionary persistence, their constancy in flux, their stubbornness?
Sea turtles evolved more than a hundred million years ago.
The two Ridley turtles, Olive and Kemps, probably evolved about 10 million
years ago and then diverged 4 to 5 million years back. Our genetic studies have
shown that the population on the east coast is ancestral to the ones in the
Pacific and Atlantic, so they have been around a long time.
How are turtles connected with the waters they swim in,
the sand they lay their eggs on, the climate they inhabit, with the rest of
nature, including human beings? How are they connected with the web of life?
Sea turtles have complex roles in the ecosystem, because of
the habitats they nest and forage in and their different diets. Green turtles
are ecosystem engineers and can completely transform sea grass meadows.
Turtles—in fact, all the creatures—affect ecosystems in
various ways, through the way they eat, procreate and live. How do turtles
transform them and what’s their role in food webs?
When I said that green turtles transform sea grass meadows,
I meant that they can actually destroy them. In Lakshadweep, they seem to feed
in one island lagoon till the sea grass has been depleted and then move on to
another one. This has caused quite a bit of conflict with fishermen, because
they believe this has led to the decline of fish in the lagoons.
It is believed that there were over a million green turtles in the Caribbean a few centuries ago. Imagine the effect they must have had. It is true that the decline of these large mega-vertebrates could have ecosystem effects. We don’t understand these effects, but we should be thinking of conservation of ecosystems as a whole.
Turtles are masters of navigation. Could you tell us how
they come here, how they live? Why here? Could you show their navigation?
Turtles navigate using the Earth’s magnetic field. They are
sensitive to its intensity as well as angle of inclination, which gives them a
compass sense. This helps them find the beaches where they were born when they
return to nest as adults. Both males and females seem to return to their natal
beaches. In some species and populations, this is very specific, i.e. they come
back to the same beaches (like Ascension
Island) and in others, it’s a bit more general, say like the east coast of
Could you talk about their oceanic lives?
As adults, hawksbills and green turtles live in island and coastal
habitats near coral reefs and lagoons with sea grass. Ridleys can be oceanic or
coastal as adults. Leatherbacks are largely oceanic and spend more time in
colder waters than any other reptile. They are able to regulate their body
temperature at several degrees above their surroundings.
What are we learning from satellite telemetry and
Satellite telemetry can tell us the exact migratory routes
of turtles, as well about the biotic and abiotic factors that determine their
routes and feeding behaviour. Their dive behaviour can also be studied using
transmitters. Apart from the scientific value of this data, tracking turtles
can identify interactions with and threats from fisheries.
Genetic studies help identify different populations and evolutionarily significant units, like the population of Ridleys on the east coast of India, which we found to be distinct from the ones in the Pacific and Atlantic. Genetics can also help connect populations in feeding grounds to breeding grounds and vice versa. It was critical in helping demonstrate the natal homing hypothesis, that turtles do indeed return to nest at the beaches where they were born.
What do turtles and their lives say about the state of
Healthy turtle populations likely indicate healthy oceans.
Or at least, that’s what we turtle biologists like to believe.
What do turtles and their lives say about the state of
our coasts. How do pollution runoffs, dead zones, oxygen-less waters affect them?
There is a lot of work on ingestion of debris such as
plastics, etc., which can be fatal for turtles. Leatherback turtles often
mistake plastic bags for jellyfish, for example. Pollution can either affect
them directly or make them vulnerable to disease.
Any particular diseases affecting them?
Fibropapillomatosis (tumours both external and internal) has
been known to affect sea turtles, particularly green turtles, in many parts of
the world. Some populations have been severely affected. There have been a few
cases recorded from Olive Ridleys in Odisha.
India’s role in turtle preservation and conservation....
what are the main ideas for conserving turtles? What ideas are yielding
There are conservation groups in every state—Prakruti Nature Club in Gujarat, Sahaydri Nisarga Mitra in Maharashtra, Canara Green Academy in Karnataka, Neythal and Theeram in Kerala, SSTCN and TREE Foundation in Tamil Nadu, VSPCA in Andhra, and several in Odisha like the Rushikulya Sea Turtle Protection Committee, Devi Sea Turtle Action Programme and APOWA in Gahirmatha. Each of these groups focuses on different activities such as beach monitoring and protection, and outreach. In addition, national organisations like WWF and Dakshin Foundation have conservation programmes at multiple sites. Several Forest Departments are also involved in sea turtle conservation, mainly through maintaining hatcheries.
Apart from listing sea turtles in Schedule 1 of the WLPA, India is a signatory to several international instruments that protect turtles such as CITES, Convention on Conservation of Migratory Species (CMS) and the CMS-UNEP MoU on the Conservation and Management of Sea turtles in the Indian Ocean and South East Asia (IOSEA)
Please talk about your work in turtle conservation.
I have been involved in sea turtle conservation since the
late 1980s when I helped set up SSTCN in Chennai. I am proud that this largely
student-led group has survived nearly 30 years and continues to generate such
enthusiasm among young people.
I started my work on sea turtle genetics in Odisha in the late 1990s and became interested in conservation issues there. We helped set up the Orissa Marine Resources Conservation Consortium in 2004, a platform for conservationists and local communities to work towards marine conservation. A few years later, my colleagues at Dakshin and I set up the Turtle Action Group which brings together all the NGOs in India for dialogue and capacity building. We produce the Indian Ocean Turtle Newsletter (www.iotn.org) and maintain a vast repository of information on the website, www.seaturtlesofindia.org.
Through Dakshin Foundation and the Indian Institute of Science, we have set up sea turtle monitoring and conservation programmes for Olive Ridleys in Odisha, leatherbacks in the Andamans and green turtles in Lakshadweep. I’ve written extensively about sea turtle conservation in India in my book From Soup to Superstar.
How is habitat loss affecting them?
Conservationists tend to get upset about issues like mortality which are just more stark and visible. A thousand dead turtles on the Odisha coast, or even a hundred on a Chennai beach, attract attention and can be disturbing. However, habitat loss is worse and potentially irreversible. Populations can recover, but beaches might not. So, coastal development, especially of the type that has irreversible impacts such as ports and harbours, can destroy nesting habitats and have worse impacts in the long term than, say, fishing related mortality, which gets much of the media spotlight. Of course, one must make efforts to curb fishery-related mortality as well, but coastal development is far more harmful in the long run.
Also, what are the losses to the wildlife trade? Why are
Sea turtles have been traded for thousands of years,
including from India and Sri Lanka to the Roman Empire. Turtle meat and eggs
were widely consumed, and the hawksbill’s is used to make various products.
There was trade in green turtles from the Gulf of Mannar till the 1960s–1970s,
and of Ridleys from Odisha to West Bengal in the 1970s, when tens of thousands
of adults were captured. However, they are protected by the Wild Life
Protection Act, and there has been little or no trade in recent years. There
may, of course, be local consumption.
There are many instances of fishermen and others who cook
and eat all the eggs when they find them. What are your ideas on saving turtles
when these things happen everywhere in India?
There are legal programmes for taking turtle eggs in some
parts of the world, notably Ostional in Costa Rica, where locals collect eggs
from the first few days of the arribada. These eggs would likely be destroyed
by later nesters. I don’t think there is anything intrinsically wrong with the
consumption of turtle meat or eggs. The problem, whether it’s turtles or fish
or any other natural resource, is sustainability. Unfortunately, it’s not
possible to have any kind of discussion about sustainable use, whether it’s sea
turtles or crocodiles or any other animal, in India, because of a strong lobby
for protection in its strictest sense.
There is a temple for turtles in Andhra. They have
enormous mythological and socio-cultural significance. Moreover, they are a
symbol for longevity, just being there all the time. Do you think conservation
practices and ideas can factor these in and help protect turtles—in fact, other
wildlife—from going extinct?
Sea turtles are revered by some communities because they represent Kurma, the second avatar of Vishnu. I have maintained that Kurma must be an Olive Ridley, since the Sri Kurmam temple is located in Srikakulam and only this species nests in large numbers there.
Could you talk about your experiences in turtle conservation
conferences? And also your role as the president.
The annual symposium on sea turtle biology and conservation
is an extraordinary event. For a taxonomic group that has only seven species
worldwide, 500 to 1,000 people attend each event, from over 70 countries.
Almost every country that has a coastline has some species of sea turtle
nesting on its beaches or in offshore waters, and biologists or
conservationists working on those turtles. In a sense, they are global
flagships for conservation. The conference is also different from many other
taxon specific conferences, in that it attracts not only academics (social and
natural scientists), but conservationists of various hues, including grassroots
community groups, national and international NGOs, activists, volunteers,
educationists and so on.
Organising it in Goa was quite a job. We had over 500 participants, over 300 international attendees, making it one of the largest ecology meetings in India. It was great to bring some of the world’s best turtle biologists to India so that the community here could get to hear about their work. My mentors, Brian Bowen, a marine evolutionary biologist and pioneer of sea turtle genetics, and Jack Frazier, a veteran of sea turtle biology and conservation, both gave keynote addresses, as did Rom Whitaker. The MOEF came through in a time of crisis and providing significant financial support. And I had a great team.
Approaches to conservation—what’s the ‘in’ thing now and
why? Can you give the low-down on how approaches changed over the years and
Conservation today is much more inclusive. Across the
spectrum, conservationists recognise that it is important to acknowledge and
involve communities and civil society. They are beginning to realise that it’s
important to incorporate principles of social and environmental justice in
their work and that local communities, especially resource dependant ones, need
to be involved in the long term management and stewardship of those resources.
ATREE, where I am currently posted as director, is a pioneering institution in India when it comes to bringing principles of environmental justice to conservation, and to integrating conservation and livelihoods. Dakshin Foundation brings the same philosophy to coastal and marine conservation issues.
Title photo: Courtesy Kartik Shanker