tag:theconversation.com,2011:/uk/topics/green-turtle-6850/articlesGreen Turtle – The Conversation2022-06-13T13:30:19Ztag:theconversation.com,2011:article/1838582022-06-13T13:30:19Z2022-06-13T13:30:19ZWe attached tracking devices to West Africa’s green turtles. This is what we learnt<figure><img src="https://images.theconversation.com/files/467692/original/file-20220608-11-g7wuc5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4968%2C3049&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A green turtle with a satellite tag at Poilão Island, Guinea-Bissau. Photo: Miguel Varela</span> <span class="attribution"><span class="source">Miguel Varela</span></span></figcaption></figure><p>Sea turtles have been swimming the world’s oceans and nesting on its beaches for over 120 million years. They even survived mass extinction events, including the one that saw the end of the large dinosaurs. </p>
<p>Throughout human history sea turtles have played key roles in the culture and diet of <a href="https://link.springer.com/article/10.1007/s00338-007-0234-x">coastal populations around the world</a>. But in modern times, over-exploitation of sea turtle meat, eggs, cartilage, oil, and body parts, <a href="https://books.google.com.ng/books?hl=en&lr=&id=9H_LBQAAQBAJ&oi=fnd&pg=PA259&dq=info:V6Ayhu7Eac0J:scholar.google.com&ots=meZAPXfFFg&sig=vsar51Ue3_AuxxfHnG-YQJwqYkM&redir_esc=y#v=onepage&q&f=false">caused</a> population declines and even local extinctions. They also face threats from plastic ingestion and climate change. </p>
<p>Among the seven species of sea turtles, the green turtle was historically <a href="https://books.google.com.ng/books?hl=en&lr=&id=SezaciNIQUIC&oi=fnd&pg=PP1&dq=Rieser+A+(2012)+The+case+of+the+green+turtle:+An+uncensored+history+of+a+conservation+icon.+JHU+Press&ots=khf3kOyiqK&sig=-3Fbb9z95c5gP_hb9-e1p1rPIaw&redir_esc=y#v=onepage&q=Rieser%20A%20(2012)%20The%20case%20of%20the%20green%20turtle%3A%20An%20uncensored%20history%20of%20a%20conservation%20icon.%20JHU%20Press&f=false">the most exploited for human consumption</a>. Green turtles are a key element of West Africa’s biodiversity heritage and contribute to the health of coastal marine ecosystems in the region. But protecting them is difficult, in part because they perform some of the longest migrations known in the animal kingdom.</p>
<p>These grand movements pose a major conservation challenge: how do we protect animals that cross international borders and can therefore experience varying levels of protection and human-caused threats? </p>
<p>We conducted <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.812144/full">research</a> around the small island of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.14520?casa_token=BAA5pYK_-dAAAAAA%3AtcFPSFiUEYjX00CNRzOMyNQRw0D77Wr6-WB54pQdhqRuYGu2v6xeXdRINcHGWOWptGcNHobu6TyF3RU">Poilão</a> off the coast of Guinea-Bissau. The island is part of the Bijagós archipelago which hosts one of the <a href="https://meridian.allenpress.com/ccb/article-abstract/8/2/150/26648/Status-Ecology-and-Conservation-of-Sea-Turtles-in">largest green turtle populations in the world</a>. The core nesting site for this population is Poilão island where around 25,000 turtles make their nests annually.</p>
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<img alt="Man and woman wearing headlamps studying a sea turtle on the beach" src="https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467693/original/file-20220608-20-4kwbjm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Researchers attaching satellite tags on a green turtle.</span>
<span class="attribution"><span class="source">French Connection films</span></span>
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</figure>
<p>In our <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.812144/full">recent study</a>, we glued tracking devices to the shells of green turtles to study their movements. These devices transmitted their locations to orbiting satellites, allowing us to know where they are in near real-time.</p>
<p>We used the turtles’ positions to map the marine areas they occupy and estimate how much time they spent within marine protected areas. </p>
<p>We found that the green turtles from Poilão connect at least five West African nations. Some turtles remained year-round in the waters of Guinea-Bissau or nearby in Guinea, to the south. Others travelled some 400 km north <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.812144/full">to feed</a> in Senegal and The Gambia, or even as far as 1000 km northwards to the Bay of Arguin, in Mauritania. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467752/original/file-20220608-18-y32hg4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Feeding sites of West Africa green turtles.</span>
<span class="attribution"><span class="source">Usifo Omozokpea / Frontiers in marine science</span></span>
</figcaption>
</figure>
<p>We concluded from our findings that meeting the challenge of protecting the sea turtles calls for international cooperation for conservation coupled with an understanding of the geographic connectivity that they create.</p>
<h2>The life-cycle of green turtles</h2>
<p>When newly hatched green turtles emerge from the nest, they quickly crawl to the sea and soon disappear from sight. </p>
<p>They spend the first three to five years in the vast open ocean,
after which they approach the coast to settle in areas rich in food.</p>
<p>For a green turtle, <a href="https://www.int-res.com/abstracts/esr/v23/n1/p51-62/">beds of seagrass and macroalgae are the typical habitats they seek for nourishment</a>.</p>
<p>Female green turtles <a href="https://www.int-res.com/abstracts/esr/v23/n1/p51-62/">only reach adulthood at about 20 years old</a>, at which point they return to lay their eggs on the same sandy beach where they emerged as hatchlings all those years ago.</p>
<p>After breeding, they return to their feeding grounds and take a much needed break from travelling, mating, making and laying eggs, <a href="https://repository.library.noaa.gov/view/noaa/4922">which usually lasts about three years</a>.</p>
<p>The beach at Poilão is patrolled by conservation teams during the peak of the nesting season (August to November), granting protection to the turtles that come ashore to nest. But turtles don’t stay long on the beach. Within two hours they have laid their eggs and returned to the sea. </p>
<p>Throughout the course of a breeding season, females lay between three and six clutches of eggs, at 12-day intervals, after which they migrate to their feeding grounds.</p>
<p>As green turtles are known to migrate sometimes thousands of kilometres between nesting and feeding areas, knowing their whereabouts is essential to assessing what threats they may face along the way. For example, if turtles were heavily captured for their meat at faraway feeding areas, the efforts in place on the nesting beaches of Poilão would be fruitless.</p>
<p>Studying the movements of turtles from the Bijagós Archipelago was therefore necessary to understand what level of protection the population has while at sea.</p>
<h2>Revelations from satellite tracking</h2>
<p>The research was conducted in partnership with biodiversity managers from Guinea-Bissau, Senegal and Mauritania, and provides a scientific basis for decision-making on effective conservation measures. </p>
<p>Based on the movements of the turtles, we were able to provide recommendations for conservation managers on how they could improve protection of important sites.</p>
<p>For example, we show for the first time that most of the coastal waters of the Bolama-Bijagós Biosphere Reserve in Guinea-Bissau are used as feeding grounds by this population. This is a strong argument for implementing fishing regulations in this reserve to reduce the risk of turtles being captured in fishing gear. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A turtle swimming in the water" src="https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467694/original/file-20220608-223-dupy0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Poilão Island is a popular nesting place for green turtles.</span>
<span class="attribution"><span class="source">Miguel Varela</span></span>
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</figure>
<p>Our findings <a href="https://www.frontiersin.org/articles/10.3389/fmars.2022.812144/full">also show that the Regional Network of Marine Protected Areas of West Africa</a> encompasses most of the habitats used by this important population. Turtles spent over 90% of their time inside the boundaries of the area during breeding, and 78% of their time when foraging.</p>
<p>However, we also identified locations, particularly during migration, where protection could be improved.</p>
<p>Our findings also have relevance for local communities in the region. For the Bijagós people it is a matter of pride that green turtles travel from so many different places to nest on their pristine beaches. Likewise, the Imraguen people, the sole residents of the Banc d’Arguin National Park, take pride in maintaining productive waters with vast seagrass beds, where green turtles can flourish. </p>
<p>Additionally, healthy sea turtle populations can promote eco-tourism through turtle watching activities, suggesting that the successful conservation of this globally important population may be economically beneficial to people across the region.</p><img src="https://counter.theconversation.com/content/183858/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Protecting green turtles is difficult because they perform some of the longest migrations known in the animal kingdom.Ana Rita Patricio, Postdoctoral research fellow, University of ExeterMartin Beal, Research Assistant, ISPALicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/293402014-07-22T04:34:50Z2014-07-22T04:34:50ZSpace tracking reveals turtles’ record-breaking ocean swim<figure><img src="https://images.theconversation.com/files/54415/original/68cbjxcv-1405928947.jpg?ixlib=rb-1.1.0&rect=32%2C18%2C3089%2C2319&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Green turtles can travel immense distances using stored fat reserves.</span> <span class="attribution"><span class="source">R.D Kirkby & B.S Kirkby</span></span></figcaption></figure><p>A satellite-tracking study of green turtles in the Indian Ocean has rewritten the record books for long-distance marine animal migration, showing that they can travel some 4000 kilometres without stopping for food. </p>
<p>The turtles roam far beyond the borders of large marine protected areas, raising questions about whether large marine parks, in isolation, offer enough protection for migratory species.</p>
<p>The <a href="http://chagos-trust.org/about/chagos-marine-reserve">Chagos Archipelago protected area</a> covers 640,000 square kilometres around the isolated group of islands in the middle of the Indian Ocean. When it was set up in 2010 it was the world’s largest marine protected area and supports some of the most pristine coral reefs.</p>
<p>My colleagues and I <a href="http://onlinelibrary.wiley.com/doi/10.1111/cobi.12325/abstract">monitored the movements</a> of the green turtle, a migratory species that breeds on the Chagos Islands. We attached small tags to the shells of eight nesting turtles, and then tracked them by satellite for more than a year.</p>
<p>Seven of the eight tracked individuals visited distant foraging grounds outside the protected area, with some travelling around 4000 km to mainland Africa. Only one of the turtles stayed inside the protected area after the breeding season had finished.</p>
<h2>Tropical travellers</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/54416/original/6z5f89h2-1405929071.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Are marine parks up to the job of protecting such wide-roaming species?</span>
<span class="attribution"><span class="source">R.D Kirkby & B.S Kirkby</span></span>
</figcaption>
</figure>
<p>Green turtles are found in tropical and subtropical waters, mainly in the Atlantic and Indo-Pacific. They are <a href="http://www.iucnredlist.org/details/4615/0">officially endangered</a>, and are hunted both legally and illegally for food. They also fall victim to fishing by-catch or boat collisions as they move through the sea. </p>
<p>Green turtles are some of the most accomplished long-distance travellers on the planet. Several decades ago the migration of green turtles was documented between their isolated nesting beaches on Ascension Island, in the middle of the Atlantic, and their feeding areas more than 2000 km away on the Brazilian coast. This was thought to be the longest migration this species could undertake. The navigational feats of animals finding remote targets in the vast ocean expanses have continued to perplex scientists. </p>
<p>Green turtles need extraordinary physiology to complete these journeys. They are vegetarian, feeding on sea grass and seaweed. On this diet, green turtles can grow to 1.5 metres in length, weigh around 300 kilograms, and live for many decades. Yet during their long migrations they do not feed, relying instead on stored fat reserves. Similar-sized warm-blooded mammals, like seals or dolphins, would be unable to complete such a trip without starving to death.</p>
<h2>Whole-life protection</h2>
<p>Our work shows that networks of small protected areas need to be developed alongside larger ones, so species that migrate long distances can stay in safe zones for as much time as possible. The Chagos Archipelago protected area certainly has huge conservation benefit. As well as protecting coral reefs and other important habitats and species, it will also protect turtles during key periods of their lives, during nesting and incubation. </p>
<p>But international cooperation will be required to develop the network of small protected areas across the Indian Ocean that will be needed to protect the turtles at other times of their lives. </p>
<p>The challenge will be to translate our results into some real-world impact, in terms both of maintaining large marine parks, and of establishing effective networks of smaller protected areas to work alongside them. </p>
<p>Turning scientific findings into real-world conservation measures will help not just sea turtles, but also the many other endangered species that need our help too. </p><img src="https://counter.theconversation.com/content/29340/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graeme Hays does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A satellite-tracking study of green turtles in the Indian Ocean has rewritten the record books for long-distance marine animal migration, showing that they can travel some 4000 kilometres without stopping…Graeme Hays, Professor of Marine Science, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.