{"id":4012,"date":"2022-04-12T22:00:00","date_gmt":"2022-04-12T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=4012"},"modified":"2022-03-28T05:57:18","modified_gmt":"2022-03-28T05:57:18","slug":"how-we-discovered-that-sea-turtles-in-seychelles-have-recovered-from-the-brink","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/how-we-discovered-that-sea-turtles-in-seychelles-have-recovered-from-the-brink\/","title":{"rendered":"How we discovered that sea turtles in Seychelles have recovered from the brink"},"content":{"rendered":"\n
\n \n
\n \n Rich Baxter<\/span>, Author provided<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\nApril Burt<\/a>, University of Oxford<\/a><\/em>; Adam Pritchard<\/a>, University of Exeter<\/a><\/em>, and Cheryl Sanchez<\/a>, University of Pisa<\/a><\/em><\/span>\n\n

It\u2019s not always easy to assess whether animal conservation measures have worked. But we\u2019ve discovered that green turtles of Seychelles \u2013 once almost hunted to extinction \u2013 are now thriving again. And it\u2019s all because of crucial protection that was given to the species around 50 years ago.<\/p>\n\n

Today, sea turtles are a well-loved<\/a> icon for conservation, their image used worldwide to remind us why we need to clean up and protect our oceans. But back in 1888, turtle meat was the order of the day \u2013 with turtle soup<\/a> a hugely popular delicacy throughout Europe.<\/p>\n\n

One of the popular hunting grounds was the Seychelles archipelago in the western Indian Ocean, and in particular, an isolated place called Aldabra Atoll, one of the largest atolls<\/a> in the world. <\/p>\n\n

Around 12,000 turtles a year<\/a> were hunted, resulting in Aldabra\u2019s green turtle (Chelonia mydas<\/em>) population collapsing to critically low levels \u2013 surveys carried out from 1967 to 1968 found no evidence<\/a> of either recent or old nesting activity on the settlement beach, which was the targeted location for harvesting nesting turtles. <\/p>\n\n

That was a turning point for Aldabra.<\/p>\n\n

The Royal Society (an eminent scientific organisation in the UK) recommended<\/a> that the atoll should become a nature reserve with complete turtle protection \u2013 and on August 13 1968 the Green Turtle Protection Regulations were implemented throughout the territory (which was under British rule at the time but gained independence in 1976). Since then many other protective area designations have been put in place in recognition of Aldabra\u2019s importance to the natural world, including selection as a Unesco World Heritage site<\/a> in 1982. <\/p>\n\n\n\n

Thanks to all of these measures green turtles have remained largely undisturbed at Aldabra since 1968, and the effect of the protection has been astounding. As we report in our recent study<\/a> in the journal Endangered Species Research, Aldabra now has the second-largest green turtle breeding population in the western Indian Ocean region. <\/p>\n\n

Monitoring the turtles<\/h2>\n\n

Since the 1970s, the Seychelles Islands Foundation (Sif) \u2013 a public trust that took ownership of Aldabra\u2019s management in 1979 \u2013 has worked with Dr Jeanne Mortimer, a turtle scientist, on a rigorous turtle-track monitoring programme to record the turtles\u2019 recovery. <\/p>\n\n\n\n

The survey effort has been atoll-wide with the most frequent surveys on the 2km settlement beach. It is walked every morning by an Aldabra ranger to count the number of \u201cturtle nesting emergences\u201d \u2013 that\u2019s when a female comes out of the sea to attempt to nest and is recorded by counting the number of turtle tracks on the beach from the previous night. One female will leave one up and one down track \u2013 and rangers are able to distinguish between when she has actually laid eggs and when she has aborted the attempt.<\/p>\n\n

From 1980-2019 over 128,000 turtle tracks across 44,000 turtle track surveys were recorded. So, under the guidance of Professor Brendan Godley, we worked with Sif to analyse this huge dataset.<\/p>\n\n

Green turtle nests were found to have increased by between 410% and 665% since those early 1968 estimates, from around 2,500 to around 15,000 nests annually by 2019 \u2013 an estimated 2.6% annual growth rate in nest numbers. That equates to between 3,000\u20135,000 female turtles nesting each year at Aldabra today, because each female will nest several times each season.<\/p>\n\n

Notably, the greatest increase was seen at settlement beach, which is the longest beach on the atoll and, historically, the hardest hit by exploitation.<\/p>\n\n

Estimates for Aldabra\u2019s turtle population before peak exploitation were as high as 8,000 nesting females per year<\/a>, suggesting the current population could double again.<\/p>\n\n

We also uncovered many other interesting patterns in the detailed data.<\/p>\n\n

There were almost twice as many nesting attempts abandoned by the nesting females because of obstacles on the beach, such as steep banks from coastal erosion and, potentially, also a result of increased litter<\/a> washing up on the beaches.<\/p>\n\n\n\n

We also saw a potential shift in the nesting patterns of the turtles with peak nesting activity happening later in the year, perhaps a shift in their breeding season due to climate change<\/a>. <\/p>\n\n

More animal success stories<\/h2>\n\n

Similar recoveries have now been recorded in green turtle populations in Australia<\/a>, Costa Rica<\/a>, Hawaii<\/a>, Mexico<\/a> and on Ascension Island<\/a>. All of these successes highlight the value of protecting nesting areas for species recovery. <\/p>\n\n

And the benefits don\u2019t end there. The protection of habitats at Aldabra has not only been a lifeline for marine turtles in the region but a whole range of other species too \u2013 not least, the iconic Aldabra giant tortoise<\/a> that was also close to extinction as a result of extensive harvesting from Aldabra. It now has the largest population of giant tortoises worldwide.<\/p>\n\n\n\n

The atoll is also the only site in Seychelles where dugongs \u2013 a sea cow related to manatees \u2013 are found<\/a>, which is probably linked to the healthy seagrass beds that the turtles maintain through grazing. <\/p>\n\n

The importance of marine turtles<\/a> to ecosystems is widely acknowledged \u2013 but there are still a number of huge threats to these iconic animals that no amount of protection at Aldabra can stop, including unsustainable fisheries, climate change and plastic pollution.<\/p>\n\n

But undoubtedly protected sites are a crucial tool for regional ecosystem recovery and health, and the Aldabra story can serve as encouragement to conservation efforts around the world. It shows that, given the chance, animals have an extraordinary capacity to recover from the brink.\"The<\/p>\n\n

April Burt<\/a>, PhD Candidate, Conservation, University of Oxford<\/a><\/em>; Adam Pritchard<\/a>, Visiting Researcher in Conservation, University of Exeter<\/a><\/em>, and Cheryl Sanchez<\/a>, PhD Candidate, Biology, University of Pisa<\/a><\/em><\/span><\/p>\n\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"Rich Baxter, Author provided April Burt, University of Oxford; Adam Pritchard, University of Exeter, and Cheryl Sanchez, University…\n","protected":false},"author":23,"featured_media":4013,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[11],"tags":[193,474],"class_list":{"0":"post-4012","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-nature","8":"tag-conservation","9":"tag-the-conversation","10":"cs-entry","11":"cs-video-wrap"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/4012","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/users\/23"}],"replies":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/comments?post=4012"}],"version-history":[{"count":2,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/4012\/revisions"}],"predecessor-version":[{"id":4019,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/4012\/revisions\/4019"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media\/4013"}],"wp:attachment":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media?parent=4012"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/categories?post=4012"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/tags?post=4012"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}