Sea Turtles Often Get Lost for Miles, but Always Find Their Destination
By Elizabeth Claire Alberts
When baby sea turtles hatch from their eggs, they skitter across the sand to the shoreline before disappearing into the open ocean. Many years later, by some remarkable feat, female turtles find their way back, sometimes traveling thousands of kilometers, to arrive at the exact beach where they were born. This time, it's to lay their own eggs.
It's believed that turtles use the Earth's geomagnetic field to find their way, but there is still a lot that's unknown about this process. A team of scientists, who published a new paper in Current Biology this month, used satellite tracking to study the navigation skills of female green turtles (Chelonia mydas). They found that while green turtles eventually arrived at their preferred destination, they didn't always get there with pinpoint accuracy, but followed a kind of "crude map."
A green turtle in Martinque. Michelle Roux / Coral Reef Image Bank
"I think we had this idea that turtles were running on rails, and that they had some sort of fine scale navigational ability," Alex Rattray, co-author of the paper and research fellow at the School of Life and Environmental Sciences at Deakin University in Australia, told Mongabay. "But what we found out is that they make mistakes, they miss their targets, they overshoot the targets, and they do a lot of searching."
Nesting grounds aren't the only locations sea turtles habitually return to — they also return to the same foraging grounds. In fact, another study found that migrating sea turtles were so loyal to their preferred foraging locations that they would bypass other suitable places to forage while searching for their "home" site. Green turtles, in particular, demonstrate a very high fidelity to foraging grounds, and do not stop anywhere else during open-ocean crossings, according to the study, which makes the species an ideal subject matter.
The research team collected data by fitting satellite trackers to 35 sea turtles nesting on the island of Diego Garcia in the Indian Ocean. The trackers transmitted high-accuracy Fastloc-GPS location data several times each day. Once the turtles laid their eggs, they returned to the ocean to travel to their foraging grounds off the coasts of small, isolated islands. But most of the time, the turtles did not get there directly, sometimes traveling several hundred kilometers off course before reaching their destination.
"We were also surprised at the distance that some turtles migrated," Graeme Hays, lead author of the study and the Alfred Deakin professor of marine science at Deakin University, said in a statement. "Six tracked turtles travelled more than 4,000 kilometers [2,500 miles] to the east African coast, from Mozambique in the south, to as far north as Somalia. So, these turtles complete round-trip migrations of more than 8,000 kilometers [5,000 miles] to and from their nesting beaches in the Chagos Archipelago."
While the green turtles traveled via circuitous routes, the study showed that they do have the ability to navigate vast swaths of the ocean, and to reorient themselves when astray.
"None of these turtles got irrevocably lost," Rattray said. "They all eventually found a way home. One of the turtles … [traveled off course] about 200 kilometers [120 miles] south of its destination after one month, and then spent another two months finding its way back to its target after it'd overshot it.
Green sea turtle. Greg Asner
"They're amazing creatures," he added, "and they truly are the number one navigators in the world."
Green turtles are an endangered species on the IUCN Red List. Primary threats include fishing net entanglement, habitat degradation, boat strikes, and egg harvesting. However, due to global conservation efforts, green turtle populations appear to be slowly rebounding.
Rattray said the team hopes its findings will help inform efforts to protect larger areas of the ocean, encompassing both the nesting and foraging grounds of sea turtles.
"Diego Garcia is a marine protected area … but they [female green turtles] are only there about 10% of their lives," Rattray said. "The rest of the time, they don't respect national boundaries. So, the conservation future of these turtles relies on the efforts of 12 to 15 governments. There has to be a concerted effort throughout the rest of the turtle's life cycle to protect them in some way."
Reposted with permission from Mongabay.
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By Gwen Ranniger
Fertility issues are on the rise, and new literature points to ways that your environment may be part of the problem. We've rounded up some changes you can make in your life to promote a healthy reproductive system.
Infertility and Environmental Health: The Facts<ul> <li>Sperm count is declining steeply, significantly, and continuously in Western countries, with no signs of tapering off. Erectile dysfunction is on the rise, and women are facing increasing rates of miscarriage and difficulty conceiving.</li><li>Why? A huge factor is our environmental health. Hormones (particularly testosterone and estrogen) are what make reproductive function possible, and our hormones are increasingly being negatively affected by harmful, endocrine-disrupting chemicals commonplace in the modern world—in our homes, foods, and lifestyles.</li></ul>
What You Can Do About It<p>It should be noted that infertility can be caused by any number of factors, including medical conditions that cannot be solved with a simple change at home.</p><p><em>If you or a loved one are struggling with infertility, our hearts and sympathies are with you. Your pain is validated and we hope you receive answers to your struggles.</em></p><p>Read on to discover our tips to restore or improve reproductive health by removing harmful habits and chemicals from your environment.</p>
Edit Your Health<ul><li>If you smoke, quit! Smoking is toxic, period. If someone in your household smokes, urge them to quit or institute a no-smoking ban in the house. It is just as important to avoid secondhand smoke.</li><li>Maintain a healthy weight. Make sure your caloric intake is right for your body and strive for moderate exercise.</li><li>Eat cleanly! Focus on whole foods and less processed meals and snacks. Studies have found that eating a Mediterranean-style diet is linked to increased fertility.</li><li>Minimize negative/constant stress—or find ways to manage it. Hobbies such as meditation or yoga that encourage practiced breathing are great options to reduce the physical toll of stress.</li></ul>
Edit Your Home<p>We spend a lot of time in our homes—and care that what we bring into them will not harm us. You may not be aware that many commonly found household items are sources of harmful, endocrine-disrupting compounds. Read on to find steps you can take—and replacements you should make—in your home.</p><p><strong>In the Kitchen</strong></p><ul> <li>Buy organic, fresh, unprocessed foods whenever possible. <a href="https://www.ehn.org/clean-grocery-shopping-guide-2648563801.html" target="_blank">Read our grocery shopping guide for more tips about food.</a></li><li>Switch to glass, ceramics, or stainless steel for food storage: plastics often contain endocrine-disrupting chemicals that affect fertility. <a href="https://www.ehn.org/bpa-pollution-2645493129.html" target="_blank" rel="noopener noreferrer">Learn more about the dangers of plastic here.</a></li><li>Ban plastic from the microwave. If you have a plastic splatter cover, use paper towel, parchment paper, or an upside-down plate instead.</li><li>Upgrade your cookware: non-stick may make life easier, but it is made with unsafe chemical compounds that seep into your food. Cast-iron and stainless steel are great alternatives.</li><li>Filter tap water. Glass filter pitchers are an inexpensive solution; if you want to invest you may opt for an under-the-sink filter.</li><li>Check your cleaning products—many mainstream products are full of unsafe chemicals. <a href="https://www.ehn.org/how-to-shop-for-cleaning-products-while-avoiding-toxics-2648130273.html" target="_blank" rel="noopener noreferrer">Check out our guide to safe cleaning products for more info</a>.</li></ul><p><strong>In the Bathroom </strong></p><ul> <li>Check the labels on your bathroom products: <em>fragrance-free, paraben-free, phthalate-free</em> and organic labels are all great signs. You can also scan the ingredients lists for red-flag chemicals such as: triclosan, parabens, and dibutyl phthalate. Use the <a href="https://www.ewg.org/skindeep/" target="_blank">EWG Skin Deep database</a> to vet your personal products.</li><li>Ditch the vinyl shower curtain—that new shower curtain smell is chemical-off gassing. Choose a cotton or linen based curtain instead.</li><li>Banish air fresheners—use natural fresheners (an open window, baking soda, essential oils) instead.</li></ul><p><strong>Everywhere Else</strong></p><ul><li>Remove wall-to-wall carpet. If you've been considering wood or tile, here's your sign: many synthetic carpets can emit harmful chemicals for years. If you want a rug, choose wool or plant materials such as jute or sisal.</li><li>Prevent dust build-up. Dust can absorb chemicals in the air and keep them lingering in your home. Vacuum rugs and wipe furniture, trim, windowsills, fans, TVs, etc. Make sure to have a window open while you're cleaning!</li><li>Leave shoes at the door! When you wear your shoes throughout the house, you're tracking in all kinds of chemicals. If you like wearing shoes inside, consider a dedicated pair of "indoor shoes" or slippers.</li><li>Clean out your closet—use cedar chips or lavender sachets instead of mothballs, and use "green" dry-cleaning services over traditional methods. If that isn't possible, let the clothes air out outside or in your garage for a day before putting them back in your closet.</li><li>Say no to plastic bags!</li><li>We asked 22 endocrinologists what products they use - and steer clear of—in their homes. <a href="https://www.ehn.org/nontoxic-products-2648564261.html" target="_blank">Check out their responses here</a>.</li></ul>
Learn More<ul><li>For more information and action steps, be sure to check out <em>Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race</em> by EHS adjunct scientist Shanna Swan, PhD: <a href="https://www.shannaswan.com/" target="_blank" rel="noopener noreferrer">available for purchase here.</a></li><li><a href="https://www.ehn.org/st/Subscribe_to_Above_The_Fold" target="_blank" rel="noopener noreferrer">Sign up for our Above the Fold Newsletter </a>to stay up to date about impacts on the environment and your health.</li></ul>
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