Ultimate guide to
Sea turtles in Asia
Read this article to learn about sea turtles in general but with a focus on sea turtles in Asia.
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Conserving Asia’s Ocean Explorers: the Migratory Sea Turtle
Sea turtles are a group of seven species of marine-dwelling turtles. Six species have hard shells – including the green, hawksbill, olive ridley, loggerhead, Kemp’s ridley and flatback sea turtles. Meanwhile, the leatherback sea turtle has, as its name suggests, a soft, leathery shell. Unlike land-living turtles, sea turtles have a streamlined shell and flipper-like front limbs, making them efficient swimmers.
Sea turtles also come in all shapes and sizes. Of the seven species, the smallest is the little olive ridley, reaching a maximum size of about 75 cm long and weighing 50 kg. The largest are the leatherbacks with a shell as long as 1.75 m, and weighing up to 900 kg!
Besides their size, each species has features that make them unique! For example, leatherbacks have shells that are black, soft, and leathery with seven ridges; hawksbills have hawk-like beaks and shells with overlapping scales; loggerheads have disproportionately large heads and beaks to crush the shellfish they love eating; and green turtles are the only species that are herbivores.
Sea turtle ecology
Sea turtles are reptiles, meaning that they are cold-blooded, breathe air using lungs, and lay eggs. Sea turtles spend most of their life at sea, but females come to land during the nesting season (usually between April and October in Asia), to lay their eggs.
During the nesting process, a female comes ashore, usually at night, and prepares her nest. She uses her flippers to make a pit (body pit) in the sand for her to lie in. Then, she digs a deeper hole (egg chamber) in the ground to lay her eggs in (usually about 80-120 eggs per nest!). After about 45-60 days, the hatchlings emerge from their eggs, and make their way towards the ocean!
Females usually nest several times during the season. For example, green turtles nest an average of 5 times per season. Nesting takes a lot of energy from the mother turtles, so most females only nest every 2-4 years. But even so, females will often return to the same beach that they nested at years ago!
When not nesting, sea turtles spend their lives at sea – breeding, sleeping, and especially feeding! Each species of sea turtles have different diets – some are carnivores (eat other animals); others are omnivores (eat a mix of sea plants and other animals); and only the green turtles are herbivores (eat only sea plants such as seagrass, seaweed and algae). Even within these diets, sea turtle species have different favourite foods. For example, leatherbacks mainly eat jellyfish; loggerheads love shellfish; and hawksbill turtles make the most of their special beaks to eat sponges and coral.
But sea turtles don’t live their lives in one place. In fact, they are nature’s ocean explorers!
Being migratory animals, sea turtles travel huge distances throughout and across oceans to feed in one place, then breed and nest in another. In fact, they are the only reptiles that take part in long-distance migrations. And these are very long distances! For example, leatherback turtles can travel up to 16,000 km in one round trip! That would be like swimming from Malaysia to South Africa, and back again! These migrations are driven by changes in the ocean environment. This allows the turtles to make the most of available resources in different areas at different times.
On one hand, sea turtles are what scientists call ‘charismatic’ animals: they are much-loved by most people and are considered pretty cool, cute, or interesting! But these beautiful reptiles are also very important to the habitats that they live in. In fact, sea turtles are known as keystone species: they play a vital role in the balance of the ecosystems that they inhabit. Without sea turtles, the incredible oceans that they live in, and all the different species that they share these oceans with, will be threatened. The migratory behaviour of sea turtles means that they play a role in many ecosystems globally.
There are lots of examples of the crucial roles that sea turtles play in ocean environments, and here are just a few:
(1) Sea turtles lay a large amount of eggs on sandy beaches, and some of these never hatch. These unhatched eggs provide nutrients to the sand, allowing other species to grow and feed here, such as monitor lizards and beach vegetation. The growth of plants near sandy beaches also keeps dunes stable.
(2) Sea turtles feed on seagrass, keeping the seagrass bed healthy. A healthy seagrass population provides habitat and nutrition to lots of other species, including seahorses and juvenile fish. Healthy seagrass also keeps the ocean floor stable. Seagrass are also major oxygen producers and carbon sinks, helping control the rise of greenhouse gases.
(3) Sea turtles play an important role in the food web: for example, leatherback turtles feed on jellyfish, which are major predators for many fish species. With leatherbacks helping keep jellyfish populations at a stable level, fish populations are not threatened.
Sea turtles are also an important species from a socio-economic perspective for various populations around the world. They have been regarded as religious and cultural symbols as well as sources of income through tourism. Further, by indirectly contributing to a healthy marine ecosystem, sea turtles contribute to the livelihood of coastal communities, especially those reliant on the harvests of the ocean’s resources.
Fun Sea Turtles Fact
1. They think jellyfish are delicious.
Leatherbacks and hawkbill turtles feed on jellyfish and keep their populations in check. Plastic looks like jellyfish when it’s floating in the water and that’s why so many turtles die from ingesting plastic—they were going for a tasty snack.
2. They cannot retract into their shell like other turtles.
Since they don’t have to protect themselves from predators for most of their life on water, sea turtles cannot retract their flippers and head into their shells. Their anatomy makes them more agile when under the sea but highly vulnerable when nesting and hatching.
3. Temperature dictates the sex of baby turtles.
Warmer nests lead to more females and cooler ones lead to more males—which is why climate change could drastically affect their populations by creating too many females and too few males to match them for reproduction.
4. They’ve been around for a very, very long time.
An estimated 110 million years is how long sea turtles have existed on Earth, which means they once shared the planet with T-Rex and other dinosaurs.
5. They can hold their breath for five hours underwater.
To accomplish this mighty feat they slow their heart rate to up to nine minutes in between heart beats in order to conserve oxygen.
7. They have an excellent sense of direction.
Sea turtles can detect the Earth’s magnetic field and they use it as a compass.
Sea turtle distribution in Asia
The Asia-Pacific region is a hotspot for the world’s sea turtles, hosting six of the seven species of sea turtles (excluding the Kemp’s ridley)! Five of the six species nest on Asian coastlines (excluding the flatback turtle). Basically every country in the Asia-Pacific region with a coastline hosts some form of nesting population. However, many sea turtles are known to nest in Malaysia, Indonesia, Thailand, Myanmar, the Philippines, Japan, China, India, Sri Lanka, and Papua New Guinea. Sea turtles pick their nesting habitat based on conditions that will be best for their eggs to be safe and healthy. In fact, many species of sea turtles can be found nesting in similar areas, or even on the same beaches! For example, the beaches in the state of Terengganu, Malaysia, have historically hosted the nesting populations of four sea turtle species – leatherbacks, olive ridleys, greens and hawksbills!
The Asia-Pacific region also provides important habitat for turtles to feed. Flanked by the West Pacific and Indian Oceans, the seas of the Asia-Pacific have a large diversity of species and environments to satisfy the dietary cravings of the sea turtles. Coral reefs (e.g. the Coral Triangle) provide food for the hawksbills and juvenile green turtles, and the seagrass beds in coastal areas provide for the green turtles. Open ocean and deeper areas with crustaceans and molluscs provide food for the loggerheads and olive ridleys. Food sources of sea turtles are not limited to one place (e.g. shellfish can also be found in coral reefs), so sea turtles are not limited to one foraging ground. For example, green turtles, especially those that aren’t adults yet, can be found going back and forth between seagrass beds and coral reefs.
As we mentioned earlier, sea turtles are migratory species, and in the Asia-Pacific region, they have been known to travel from Southeast Asia all the way to North America! Other sea turtles also choose to only migrate within the region e.g. within the Indian Ocean, between Japan and the Philippines or Malaysia and Vietnam. It’s quite evident that sea turtles show lots of variation in their migratory patterns – among and within species and populations. Clearly, we still have a lot to learn about the migratory behaviour of sea turtles, but it’s also quite clear that sea turtles have an adventurous nature and don’t stay close to home!
Conservation Concerns for sea turtles
5 species of sea turtles found in Asia are all classified under the International Union for the Conservation of Nature’s (IUCN) Red List:
- Olive ridley turtle: Vulnerable
- Green and loggerhead turtles: Endangered
- Leatherback and hawksbill turtles: Critically Endangered
The flatback turtle, which inhabits the waters of the Asia-Pacific region during its migration, does not have a classification as there is not enough data available. Given the large amount of habitat that the Asia-Pacific region provides for turtles, understanding these sea turtle populations, their movements, and the threats they face is therefore vitally important for global sea turtle conservation efforts.
So why are sea turtles endangered? There are a huge range of threats facing our ocean explorers. Sadly, Asia (particularly around Bangladesh, India, Indonesia, Japan, Malaysia, the Philippines and Sri Lanka) is the most dangerous place for sea turtles in the world.
Egg Poaching and meat eating are threats to sea turtles
During the nesting season, sea turtles and their eggs are at risk of poaching. Turtle eggs and meat are still eaten traditionally in several countries, such as Indonesia, Malaysia, the Borneo Islands and Vietnam. As a classic case, unfortunately, the overharvesting of leatherback turtle eggs in eastern Peninsular Malaysia resulted in the leatherback population disappearing from this area.
Coastal development is damaging nesting and foraging sites
Further, sea turtles lose beaches that provide vital nesting habitat when they are developed into coastal human settlements. In Pakistan, olive ridley turtles used to nest on its beaches, but have not been spotted nesting since 2013, perhaps due to human developments. Hatchlings are also affected by human developments. When baby turtles emerge from their eggs, they may be at risk of trampling on busy beaches. They may also become distracted by artificial lights and not successfully reach the ocean.
Sea turtles drown in fishing nets
When the turtles reach the ocean, or during migration, they may be caught accidentally in fishing nets. Hundreds of thousands of turtles are killed worldwide in fishing activities every year. Sometimes, people hunt turtles for their shells and meat too, and known-feeding grounds of turtles are often targeted by international fisherman. This happens commonly in the waters around Malaysia, Indonesia and the Philippines, common spots for feeding. In addition, hawksbill turtle populations have suffered greatly in Vietnam, where their shells have been sold locally, and illegally imported to China and Japan.
Turtles are at risk of being hit by boats
In places with high boat traffic such as touristic places, sea turtles are at risk of boat strikes. As sea turtles are reptiles and thus have lungs, they need to surface every few minutes to breathe. If there is an incoming boat on the way and both do not avoid each other in time, a collision happens. While the boats may not even notice, sea turtles get severe and fatal injuries, usually via propeller cuts.
The destruction of the ocean environment such as untreated waste discharge and bottom-trawling also affects the resources available to turtles, such as the seagrass beds on which they feed. Turtles may also accidentally ingest pollutants, such as plastics, that litter the ocean, mistaking them for food.
Finally, the global threat of climate change may reduce available habitat for nesting with rising sea levels. Additionally, as temperatures rise, sea turtle hatchlings may be negatively affected, as temperatures determine the sex of the hatchlings. Over time, a skew in sex-proportions of hatchlings could have severe effects on populations.
Unfortunately, two major characteristics of sea turtles put them at even more risk. Firstly, sea turtles take a long time to reach adulthood. Some species of sea turtles don’t begin to breed until the age of 30. This increases their inherent risk because it means that each turtle must survive for a long time before it is able to reproduce and contribute to its population. When fewer turtles are able to survive until adulthood, there will be a lower reproductive rate, and the population may decrease.
The long time between hatching and reproduction may also allow a ‘lag’ in negative effects. This makes it more difficult to assess the state of current populations of sea turtles. For example, if fewer turtles are born this year, we may not see a big drop in our nesting populations of turtles for several years or decades. Sadly, due to the long maturation time of sea turtles, and the many threats facing them as they grow, only 1 in 10,000 hatchlings born today are likely to make it to adulthood.
The second characteristic of sea turtles that puts them at risk is their migratory lifestyle. As described earlier, sea turtles travel tens of thousands of kilometers a year! This means that sea turtles may come into contact with many more threats than just those nearby their nesting or feeding locations. This makes effective conservation work more difficult too. We need collaborative policies to protect species on a more global scale if we want to see real protection occurring. Creating policies and coming to agreements on management is much harder to coordinate across many different countries and jurisdictions.
Above is a very informative video about the threats to seas turtles and how they can be overcome.
Sea Turtles can use all the help they can get. Learn about some historical and modern efforts to conserve these animals.
Introduction 0:00
5 species of Sea Turtles 1:14
Sea Turtle Conservancy – record year for Green Turtles, endangered species act, and more 1:44
Shrimp Trawls and Turtle Excluder Devices (TEDs) 3:43
Turtle Safe Lighting 4:38
FWC Florida Statewide Nesting Survey Program 5:25
Sea Turtle Nests in Northeast Florida 8:01
Nest Excavation I: A failed nest 11:05
Nest Excavation II: A successful nest. 14:45
Baby Sea Turtles released into the ocean! 17:46
Pip: Cartoon of baby sea turtle growing into an adult and laying a nest of her own! 19:31
What you can do 21:53
Conservation Measures for sea turtles
After learning about the many, many threats to sea turtles, you can probably see that conserving sea turtles is a huge, complex task. Fortunately, some global efforts for sea turtle conservation have been put in place, such as the Convention on International Trade in Endangered Species (CITES), which protects sea turtles from international trade.
Other international collaboration, such as determining best fishing practices to protect sea turtles is occurring. Regional collaboration is also important, such as the Northern Indian Ocean Marine Turtle Task Force (NIO-MTFF). NIO-MTFF has meetings to discuss the best-practice to reduce threats, and works to enforce policies within their own countries to protect sea turtles.
On a more local scale, nesting habitats can be protected against poaching, and disturbances can be reduced. For example, the Indonesian Government has created protected marine areas, and placed restrictions on the hunting of sea turtles.
Education and monitoring are also vital. Firstly, increasing public awareness of threats to sea turtles encourages individuals to think carefully about their own actions, and the organizations that they choose to support. Individuals may even choose to volunteer their time, or donate their money to worthy causes. Public awareness may also lead to increased pressures on governing bodies to prioritize turtle conservation.
Secondly, monitoring sea turtles helps us better understand the state of populations, and is crucial to inform effective conservation policies. There are many great conservation organizations working on the ground to protect nesting habitat, monitor populations, and increase awareness (see list at the end of this article). To help illustrate some of these conservation measures, we will use the Perhentian Turtle Project as a case study.
Perhentian Turtle Project
The Perhentian Turtle Project (PTP) is a sea turtle conservation and research project under Fuze Ecoteer Outdoor Adventures, in the Perhentian Islands Marine Park, Malaysia. The overarching aim of PTP is to help conserve the green sea turtles that feed and nest in the islands. To do this, PTP collects long-term data to monitor the turtles in the area via the photographic identification (photo ID) of each individual’s facial scale patterns.
PTP obtains photos of those facial scale patterns during
- in-water surveys where they snorkel and free dive looking for green turtles eating at a seagrass bed (Figure 6).
- night patrols where they look for nesting mama turtles and relocate her eggs into a hatchery alongside rangers from the Department of Fisheries.
- citizen science programs to encourage tourists and stakeholders to submit photos of turtles they saw during their time in the islands.
Overall, these allow PTP to estimate the population size and dynamics of the green turtles in the area to better inform subsequent conservation steps.
In addition to the turtles, PTP also works alongside community members and stakeholders via various educational programs to raise awareness of sea turtle conservation (Figure 8). Moreover, PTP’s location in the islands’ village has allowed them to form good relationships with the local community based on mutual respect. Consequently, PTP’s presence on the nesting beach and snorkel spots around the islands deters poaching and puts snorkel guides on their best behaviour.
PTP also has a strong volunteer program, which gives people from all over the world the chance to both learn more about, and directly contribute to turtle conservation!
What you can do to help
Firstly, we want to thank you for reading this article. Taking the time to learn about the amazing creatures we share this planet with. The threats they face, environmental education is such an important step for effective conservation!
We hope you might also share what you have learnt with friends and family. Learning about conservation issues encourages us to be more mindful of how we choose to live our lives, the organizations we support, and perhaps the governing bodies we choose to vote for. We may choose to reduce our plastic consumption, or reduce our carbon footprint. There are so many ways we can do this – choosing to bike or walk instead of drive, refusing to use plastic straws etc! We’re sure most of you have heard many of these great ideas, and there are lots of resources on the internet to help you with these that we encourage you to look out for.
In terms of sea turtles specifically, you may decide that you want to volunteer at a local project. That’s awesome! It doesn’t matter if you have never done this type of work before – if you care about turtles and want to help, there is surely a position out there for you! We have shared below some examples of great organizations you may choose to support. And if you want to know more, or have any questions, feel free to reach out to us :
- Perhentian Turtle Project, Malaysia
- Marine Research Foundation (MRF), Malaysia
- Kudat Turtle Conservation Society, Malaysia
- Scuba Junkie, Malaysia
- Lang Tengah Turtle Watch (LTTW), Malaysia
- Juara Turtle Project (JTP), Malaysia
- Tengah Island Conservation (TIC), Malaysia
- Sea Turtle Research Unit (SEATRU), Malaysia
- Tropical Research and Conservation Centre, Malaysia
- Large Marine Vertebrates Research Institute (LAMAVE), Philippines
- Sea Turtle 911, China
- Yayasan Pulau Banyak, Indonesia
- Sumatran Sea Turtle Conservation, Indonesia
- Sea Turtle Association of Japan, Japan
- Cambodian Turtle Conservation Project, Cambodia
- Marine Conservation Cambodia, Cambodia
- The Royal Thai Navy Sea Turtle Conservation Project, Thailand
- Kosgoda Sea Turtle Conservation Project (KSTCP), Sri Lanka
- Ningaloo Turtle Program, Australia
Watch our 5 episode Change Starts with Action series. You will learn how to reduce your negative impact on the seas and oceans that turtles call their home.
Support our causes and buy some merchandise
You can support the Fuze Ecoteer projects and supported organisations by buying their merchandise. A minimum of 60% of your fee goes directly towards the conservation cause linked to that product. The other percentage is for production costs.
Turtle Adoption
You can adopt one of our turtles in the Perhentian islands. Through our turtle photo ID database we have identified over 260 turtles that have been seen around the Perhentian Islands. Support our important conservation and adopt today.