The leatherback turtle is disappearing from its most important nesting sites in the western Pacific, according to a new study.
Female leatherback turtle on nesting beach
The study found that the number of leatherback turtle nests in the Bird’s Head Peninsula of New Guinea has dropped by a staggering 78% in the last 30 years. These beaches account for three-quarters of the western Pacific’s nesting leatherback turtles, meaning this decline could have serious consequences for the future of the species in the Pacific Ocean.
“Sea turtles have been around about 100 million years and survived the extinction of the dinosaurs but are struggling to survive the impact of humans,” said Thane Wibbels, one of the researchers.
Fishermen holding a dead, captured leatherback turtle
The leatherback turtle is the largest of the world’s turtles, and is listed as Critically Endangered on the IUCN Red List. Like all sea turtles, this species faces a range of threats, including entanglement in fishing gear, boat strikes, harvesting of its eggs by humans, and predation of its eggs by feral dogs and pigs. In addition, the leatherback turtle also accidentally consumes plastic bags, mistaking them for its jellyfish prey.
Climate change is also a serious threat to the leatherback turtle. Rising sea levels and increasingly frequent and violent storms may erode nesting beaches and destroy nests, while changing ocean currents are likely to affect the turtle’s prey.
Feral dogs are a threat to leatherback turtles, digging up and eating their eggs
The gender of leatherback turtle hatchlings is determined by the temperature at which the eggs are incubated, so warmer sand is likely to produce more females, skewing the species’ sex ratio. In addition, warmer temperatures have been known to cause abnormalities in hatchlings, and to affect the health and development of the young turtles.
In comparison to the Atlantic Ocean, where several nesting populations of leatherback turtles have increased in recent years, the status of the species in other oceans is of greater concern.
“The leatherback is one of the most intriguing animals in nature, and we are watching it head towards extinction in front of our eyes,” said Wibbels.
Conservationists have begun programmes to move leatherback turtle nests to more sheltered and shaded areas, where the eggs will be cooler, in the hope of increasing the success rate of hatchlings.
Leatherback turtle hatchlings face many perils, and very few survive to adulthood
The leatherback turtle is legally protected throughout most of its range, and a variety of other conservation measures are underway to help save this impressive marine reptile. For example, the attachment of Turtle Excluder Devices (TEDs) to fishing nets to reduce bycatch of turtles has been recommended.
However, much still needs to be done to save this marine giant. According to the researchers, a range of conservation measures need to be implemented at nesting beaches and in national and international waters if the decline of the Pacific’s last remaining leatherback stronghold is to be reversed.
Turtles took over @ARKive’s Twitter account yesterday when turtle expert Professor Brendan Godley answered your burning questions about sea turtles. We loved Brendan’s guest blogs about his turtle research and leatherback turtles, so we were delighted when he offered to take time out of his busy research schedule on Ascension Island to tweet about turtles (in temperatures of 35 °C).
And Brendan wasn’t just feeling the heat on Ascension, but also on our Twitter stream. You tweeted some tricky questions to test his expertise, but we think you’ll agree that he came up turtle trumps! Here are just some of the #turtletweet highlights:
Female flatback turtle digging nest
Turtles on Ascension
@JellicleKat You’re out on Ascension Island at the moment…how long is the nesting season, and how many females nest there? #turtletweet
In the 1930s it was down to a few hundred but now about 5000 per year. 6 month season. #turtletweet
@inthefieldnews Sea turtles return to the same beach where they hatched as juveniles to breed…but where do they go in between?
They go to one or more foraging areas that can be many thousands of miles. eg here on Ascension its Brazil #turtletweet
Top Turtle Facts
@eldenney: what’s your most interesting turtle fact? Thanks! #turtletweet
The fact that green turtles can rest at the bottom of the Mediterrannean sea for as long as 10.5 hours #turtletweet
@eldenney Cool! I can’t stay underwater for much more than 30 secs! Green turtles are impressive #turtletweet
Green turtle with turtle barnacles on its shell
@clairecjl: Hi Brendan, I was wondering how long it takes leatherbacks to reach full size? #turtletweet
This is still debated, with work to be done but anywhere between 10 and 20 years seem the best estimates to date. #turtletweet
What’s the difference between a turtle and a terrapin?
@lillashaw Hi Brendan, we were debating this in the office the other day… What’s the difference between a turtle and terrapin? #turtletweet
Its semantics N america everything can be a turtle, in UK turtle is sea, terrapin is freshwater, tortoise on land. #turtletweet
Turtles and fishing
@Jess_Cripps Do you think more could be done by fisheries to reduce the bycatch of turtles in their equipment? #turtletweet
I do. Much has been done already TEDS (trawlers), Circle hooks (longlines) and these can be improved #turtletweet
One of the great ongoing challenges is that of how to minimise bycatch in gillnets #turtletweet
Green turtle trapped in fishing net
Which species of turtles are thriving? Which are endangered?
RT @DanielsImage: @ARKive@BrendanGodley How many species of sea turtles are there? Are any thriving? #turtletweet
.@DanielsImage @BrendanGodley Big winners r Atlantic green turtles, ones struggling incl Pacific leatherbacks and hawksbills. #turtletweet
Why are turtles endangered?
@harrypurplmonky What has happened to make turtles endangered? #turtletweet
Exploited for meat and eggs for a long time &have started to recover where they r protected on beach and sea#turtletweet
The shells of green turtles, butchered alive for blood and meat
.@inthefieldnews… what would you say is the biggest threat facing sea turtles worldwide?
as with all marine biodiversity; I would say it fishing followed by climate change #turtletweet
@Jess_Cripps: Do you think turtles will start to breed earlier in response to climate change? #turtletweet
Not yet but it will soon! In Cyprus they are already 90% female…will get worse with inc temps #turtletweet
@eldenney: poor boys! #turtletweet
Kemp’s ridley turtle hatchlings
@Wildlife_Jason: What would you say is the worst problem for #turtles caused by #plasticpollution in our oceans?
“Turtles, partic babies & all leatherbacks eat it..less of a problem than fisheries though” via @BrendanGodley #turtletweet
Green turtle suffocating on plastic bag
Turtles on film
@WildscreenFest: What part does wildlife filmmaking has to play in #turtle conservation? #turtletweet
@Wildlife_Film: What did you think of the footage of baby green turtles in @BBCNature #Africa?bbc.co.uk/programmes/p01… #turtletweet
As seen on recent #Africa, there is clearly a role. MT are emblomatic #turtletweet
@Podgeosaurus: When filming do you think crews should aid baby turtles, or stay hands off? #turtletweet
Difficult one; up to individs. they shouldnt do is make things worse by releasing in daylight or hold hatchlings back#turtletweet
@lauriebelch why do some populations of turtles hatch in the day when it seems that predation risk is much higher#turtletweet
.@ARKive @lauriebelch very few do, but for obvious reasons we see more of it on film. More starlight cameras needed. #turtletweet
How can we help turtles?
@eldenney: so is there anything we can do to help turtles? #turtletweet
think about seafood choices, climate change and your role, get involved or help those who are.#turtletweet
@DanielsImage: Our support $ only go so far. Are there any organizations to support turtles you favor? #turtletweet
If I was to plump for one I would choose @seaturtle .org which is a one man show, no overheads and has transformed the field
@dodger_wake Some may not like it can we not ‘farm’ the endangered turtles to allow survival rates for eggs to raise then release
It’s done in the Cayman Islands for over 40 years, adults are now returning that were released #turtletweet
Cute or shocking photos?
@wild_photos: Our question for @ARKive’s#turtletweet! What do you think is more powerful in conservation: cute turtle images or ones showing turtle loss?
.@colaciregui @wild_photos @KACHUGABUT pictures of baby turtles always draws a gasp from the crowd! :)
Young hawksbill turtle caught in a fishing net
@harrypurplmonky Wow what a #turtletweet! TY @ARKive & @brendangodley Harry’s learned so much about turtles & conservation!… http://fb.me/KGOX0CX8
@Wildlife_Jason @BrendanGodley @ARKive Thanks for an informative #turtletweet time! :)
We’d like to join our followers in thanking Professor Brendan Godley for his turtle-takeover – informative, thought-provoking, and turtle-tastic!
Get regular updates from Brendan by following him on Twitter @brendangodley, and check out his recommended top tweeters: @UoExeterCEC, @EcoSoc_Tremough, @LifeNatureMag and @BioBlitzTremou.
Would you like to see more twitter takeovers? What topics would you be interested in? Follow @ARKive and let us know!
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Like many of you out there, the ARKive team find marine turtles utterly fascinating – they have such interesting life cycles, and are so prehistoric-looking yet are totally adorable. Who doesn’t squeal with delight when Crush from Finding Nemo pops up on the TV screen?! We decided to catch up with one of the world’s leading sea turtle experts, Professor Brendan Godley, to have a chat about these wonderful reptiles, and find out more about the conservation work Brendan is involved with.
Hi Brendan, welcome to the ARKive blog! Can you tell us a little bit about yourself? Where and what did you study?
I am Professor of Conservation Science at the University of Exeter’s Centre for Ecology and Conservation in the picturesque Cornish town of Penryn, near Falmouth. Originally from Scotland, I began studying turtles in 1989, as a 19-year-old zoology student, when I took part in a Glasgow University student expedition to Trinidad. I completed a vet degree and then went on to do a PhD on the ecology of sea turtles, including causes of mortality.
Why sea turtles? What is it about them in particular that made you want to study them?
At the tender age of 19, I was intoxicated by the mixture of excitement of seeing turtles crawling out of the dark Caribbean Sea, the joy of being in such a colourful and vibrant place, and the satisfaction of overcoming the trials and tribulations of fieldwork. The fact that sea turtles were of conservation concern and that so much was yet to be known about their biology meant that I found a raison d’être, and my path was set.
Sea turtles are incredible animals; those that nest on Ascension Island live in Brazil, which means they have to swim across the whole Atlantic to breed. Incredibly, some of the females we have observed there have lost all but a stump of one of their front flippers and have still managed to make it. I think this is the kind of robustness that has allowed sea turtles to be among the great survivors.
Where else in the world does your research take you? Do you have a favourite location to work in?
I used to spend ten months of the year in the field, but now I am more UK-based because I need to be at the university during the academic year in order to teach conservation students from around the world. My research group, however, supports long-term monitoring and conservation efforts for green turtles in Northern Cyprus, on Ascension Island, and on the Cayman Islands – all places I often visit for bouts of fieldwork. I really cannot pick a favourite location as they are all so different. I feel lucky to be exposed to the variety of people, habitats, conservation problems and research questions associated with each of these field sites.
Green turtle swimming over reef
You mentioned green turtles – what are the main threats to this species at present? What are the conservation difficulties for this particular species?
Sea turtles face a range of threats. Principal among these are direct and indirect capture in fisheries, habitat loss and degradation, pollution and climate change. At the moment, the main threat facing green turtles is that they are still quite heavily exploited for food in many places, and some of these harvests may not be sustainable. Many people have heard of turtle soup. This was mainly made from green turtles, millions of which were exploited for centuries, leading to a drastic reduction in their numbers. The good news is that their populations have started to rise very fast in many places where people are not so dependent on the direct exploitation of wild living resources, and where harvests, especially of adult turtles, have been stopped.
What is your green turtle research focus at the moment?
In recent years, we have been trying to take our work away from the nesting beaches, so we have been using techniques such as satellite tracking, genetics and in-water studies to gain an understanding of turtle migratory routes and key foraging areas. We recently collaborated with a crowd of international researchers to analyse green turtle satellite tracking data from around the world. Interestingly, we found that a notable proportion of turtles were utilising the small proportion of sea that is covered by Marine Protected Areas (MPAs). This does not seem to have happened by chance, and may reflect the fact that these areas are better protected, or that sea grasses, which green turtles eat, are featured within Marine Protected Areas (MPAs). Either way, it is an intriguing conservation finding. You can read the paper here.
Green turtle nesting on Ascension Island
That all sounds really interesting! Can you tell us a funny anecdote stemming from your work with green turtles?!
Turtle work can be very tiring, especially in the peak of the season when you’re up working on the beaches all night and the heat makes it difficult to sleep in the day. Equally, green turtles undertake a great deal of work to cover their nests, often moving tonnes of sand and digging a trench up to ten metres long. There was one occasion where one of our students in Cyprus was observing a turtle laying her clutch and must have nodded off. When I returned to team up with the student I couldn’t find him. Amazingly – although luckily not life-threateningly – he had managed to sleep through the process of being almost completely buried by the female as she covered her eggs.
Oh goodness! A lucky escape! Lastly, what is your favourite green turtle photo on ARKive?
There are many beautiful and impactful pictures, but two stood out for me. Firstly, the turtle trapped in the net, as it highlights the threat of the impacts of fisheries.
Green turtle trapped in fishing net
Additionally, the female nesting in plastic resonates quite profoundly. No matter where I go in the world, even the remotest nesting beaches far from human habitation, plastic is there on the beaches. This is clearly a problem that is going to worsen in coming years.
Debris on green turtle nesting beach
Those certainly are powerful images. Thanks, Brendan, we’ll catch up with you again soon!
An unusual species of turtle has been found to excrete waste substances through its mouth, according to a team of scientists in Singapore.
The scientists were puzzled by the behaviour of the Chinese softshell turtle (Pelodiscus sinensis) as, despite needing to breathe air, it often submerged its head in water for up to 100 minutes at a time.
When they studied the turtle in the lab, the team found that it regularly dipped its head into water and rinsed it through its mouth. The rhythmic motion of its throat, not to mention the fact that it did not drown, indicated that it was still ‘breathing’ while submerged.
After testing the water, the scientists found increased levels of the chemical compound urea, a nitrogen-rich waste substance that is excreted by most vertebrates via the kidneys and passed out as urine. In turtles, urea normally passes out of the cloaca, a single orifice used for excretion and for reproduction.
However, the team’s findings showed that the Chinese softshell turtle excretes significantly more urea through its mouth than through its cloaca. This adds to previous research that indicated that this species has highly specialised mouth tissues, a fact first discussed over a century ago when it was suggested that their velvety mouth functions in a similar way to fish gills. The findings of the research have been published in The Journal of Experimental Biology.
According to Professor Ip Yuen Kwong, one of the researchers, “These results indicate for the first time that [mouth tissue] processes and rhythmic [throat] movements were involved in urea excretion in P. sinensis.”
“We were greatly surprised by our novel results because it is generally accepted that the kidney is responsible for the excretion of urea in vertebrates – except fish,” he said.
The Chinese softshell turtle is typically found in swampy, brackish water, and the scientists have suggested that the ability to excrete urea via the mouth may have helped this and other soft-shelled turtles to successfully invade brackish and marine environments.
To produce urine in the kidneys, the turtles would have to regularly take in water, which would be harmful when the water is too salty. By simply rinsing its mouth with the brackish water, the turtle can avoid the problems associated with drinking it.
The Chinese softshell turtle may also be able to take in oxygen through its mouth tissues.
Considered a delicacy in many parts of Asia, this species is farmed in vast numbers for food, but its wild populations also continue to be exploited. As a result, the Chinese softshell turtle is in decline, and has been classified as Vulnerable on the IUCN Red List.
The 23rd of May is World Turtle Day – a whole 24 hours dedicated to highlighting the plight of the 300 or more turtle species around the world. Here at ARKive we thought we would celebrate by sharing our top turtle facts.
Did you know…
Turtles are found on every continent, except for Antarctica
The age of most juvenile turtles can be determined by the upper shell, which grows each year from a central point
Turtles are thought to have lived on earth for over 200 million years
The sex of most turtle hatchlings is dependent on the temperature which they are incubated at, with males hatching at low temperatures and females hatching when the temperature is higher
Loggerhead turtles are regularly caught as bycatch along their migration routes
The loggerhead turtle has powerful jaws that can make easy work of its hard-shelled prey.
It is highly migratory and is known to cross oceans.
Not a jack in a box
Ornate box turtles are popular pets in in Europe and the United States
Box turtles gain their common name from their hinged shell which enables them to completely close their shell to protect themselves.
The male ornate box turtle has enlarged claws on its hindfeet to grip onto the female while mating.
The greatest threat to the leatherback turtle is thought to be the effects of climate change
The leatherback turtle is the world’s largest turtle, with the average carapace (the shell covering the back) reaching around 160 centimetres and the largest recorded individual weighing up to 916 kilograms.
Uniquely, the leatherback turtle is able to maintain an elevated body temperature, giving it the ability to dive to depths of up to 1,000 metres in pursuit of prey.
Snappy by name, snappy by nature
The alligator snapping turtle is used as an ingredient in the delicacy 'turtle soup'
The alligator snapping turtle is nicknamed the ‘dinosaur of the turtle world’ due to its prehistoric, alligator-like appearance, from which it gains its common name.
The tongue of the alligator snapping turtle has a small, worm-like projection, which is wiggled to attract prey.
What is being done to help?
Shrimp fisheries are now using Turtle Excluder Devices, which only allow shrimp-sized objects to enter the nets, preventing turtles from being caught as bycatch.
Many species are now listed on the Convention on International Trade in Endangered Species (CITES), which means that international trade is strictly monitored and controlled. This should hopefully prevent some collection of wild turtles for the international pet trade.
Some nesting sites are protected during the nesting season to ensure that eggs cannot be collected and subsequently sold.
The protection of areas which are known to support turtle populations, as well as captive breeding programmes, could ensure the long term survival of these magnificent and fascinating reptiles.
Global warming poses a major threat, as populations have begun to show skewed sex ratios, with higher temperatures meaning more females than males. Although global warming is unlikely to be reversed, reducing greenhouse gas emissions may limit some damage.