Climate change effect on turtles
Published on: Monday, June 14, 2021
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Dr Pilcher with a green turtle for scientific study.
A few weeks ago, on the 23rd of May, world turtle day was celebrated to raise awareness for turtles, tortoises and their habitats. Turtles are iconic species of the marine environment and although adored by most, nearly all the species of marine turtles are now classified as endangered.  

Why is this? Is it possible that by studying them, to protect them, we are able to gain a better understanding of the state or our planet? 

The ancestors of marine turtles date as far back as 130 million years ago, when dinosaurs were walking the Earth.

Since then, they have changed very little. Turtles have kept many of their ancestors’ characteristics, such as the outer shell (known as a carapace), their beak-like jaw and legs that are modified into flippers.

Today there are seven species of sea turtle and six of these can be found within the coral triangle. 

In the latest episode of Scubazoo’s Borneo Ocean Diaries, local presenter Alex Alexander continues her journey of discovery of the marine environment.

This week she teams up with Dr Nicolas Pilcher, Founder and Director of the Marine Research Foundation (MRF), based here in Sabah, to learn more about sea turtles found locally.

Alex, Dr Nick (as he prefers) and the rest of the MRF team of Malaysian scientists and researchers, head out to Mantanani, a small island off Kota Belud, to take part in a long term study on the impacts of climate change on turtles, that includes capturing them via a ‘turtle rodeo’. 

As exhilarating as it sounded, Alex was not sure how jumping off the side of a speeding boat onto a swimming turtle, in shallow water, could help the scientists or the turtles, but Dr Pilcher was there to explain; “Turtles generally are captured using one of two techniques: the first is a passive technique that involves putting a net out and waiting for turtles to swim into it.

This only really works if turtles are actively moving from one place to another.

It really would not work on Mantanani, because the turtles are generally not moving much as they rest or feed in the shallow reef environment.

The second most common method involves what is known as ‘rodeo’ captures, where a diver jumps and catches the turtle by hand.

These captures are quick, the diver can carefully grasp the turtle, resulting in minimal stress.

Our work over the years has recaptured the same turtles on multiple occasions, evidence that they are not overly perturbed by the action.

Rodeo captures are used by some of the world’s finest sea turtle scientists as the most efficient and stress-free way to catch turtles for scientific studies.” 

Alex had five days ahead of her on board the research boat, Tortuga Madre (Mother Turtle in Spanish) with the MRF turtle catching team. But what happens next? Catching a turtle is one thing, and as it turned out an incredibly difficult thing; but, what can we learn from the turtle once caught? As a long-term project, it turns out we can learn a lot. Dr Pilcher continued; “Mantanani is a site where we run (what is now) SE Asia’s longest running in-water research project on sea turtles.

The project started out in 2006 as a way to find out if local hatchery practices were resulting in an excess of female hatchings.

They were. We determined this by combining laparoscopy (a small surgical procedure) with genetics, and figured out that most of Mantanani’s young turtles come from areas where hatcheries were not using as much shade as was needed to produce a proportion of male turtles.” 

These studies by the MRF team are being implemented because the sex of a turtle is temperature dependent, and if the temperatures in the nest rise above a pivotal temperature more females develop and hatch; conversely, if nest temperatures are cool and drop below the pivotal temperature more males develop and hatch.

This could have major repercussions in the face of climate change. Dr Pilcher explains; “With a warming planet, we expect the atmosphere and the seas to get warmer, and therefore also the nests where turtles deposit their eggs.

If eggs incubate at warmer temperatures, we may see a skewed production of females again.

So Mantanani is now much of an ongoing watchdog in terms of understanding the impacts of climate change on sea turtles.”

So we can already see that these local studies can give us an indication of what is happening on a global scale. As Dr Pilcher says, “Every year we can look at the ratio of males and females and better understand how our climate does, or may be, impacting natural sea turtle stocks.

It can also act as an advance warning tool: if we see highly skewed female turtle stocks, hatcheries in Sabah, Sarawak and Peninsular Malaysia, where many of Mantanani’s turtles come from, we could do things like add more shade to the nests to lower incubation temperatures.

These ‘management interventions’ may be what saves sea turtle populations. Our project provides Malaysia - indeed much of the world - with the very knowledge it needs to make decisions like this.”

There are many scientists in Sabah that are undertaking groundbreaking research that is contributing to our understanding of the world’s marine environment.

Join Alex as she continues to discover more about the oceans and how we can help protect them. 

What can you do to help sea turtles? There are some simple steps that anyone can follow and if everyone does, would make a real difference:
  1. Do not buy tourist souvenirs from turtles or turtle parts, such as the shell.
  2. Do not eat turtle meat or eggs.
  3. Avoid littering, by responsibly placing all trash in public refuse bins or taking it home with you.
  4. Cut down on the amount of plastic you use.
  5. Spread the word about these issues that threaten turtles. The new series of Borneo Ocean Diaries will be shown for free on www.scubazoo.tv with the latest episode released on the 14th June 2021. 

To see more of Borneo Ocean Diaries, and many other natural history productions, please visit www.scubazoo.tv. Follow Scubazoo on Instagram and Facebook: #scubazoo

Dr Pilcher and Alex discuss the research on green turtles in Sabah.


Alex about to release a green turtle.


A green turtle feeding on seagrass.






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