‘Not related to the lockdown’
Once hatchlings break out of their shells and climb up the steep wall of their nest, they skitter across the sand toward the ocean, guided by the moonlight. During this journey, these tiny animals memorize the sand and shoreline, enabling them to return to this same spot when, a few decades later, it’s time for them to build their own nests.
Humans tend to be the biggest disturbance to sea turtle nesting. Something as simple as walking on the beach at night can scare away a nesting mother, and result in what’s called a “false crawl.”
“The turtle will return to the ocean, leaving just tracks, without laying any eggs,” Perrault said. “Sea turtles may expend precious energy reserves crawling onto the beach without actually laying their eggs. Furthermore, sea turtles have a window of time when they can lay their eggs, [and] if they false crawl at the end of this window, they may even drop their eggs in the surf or the ocean, causing embryonic mortality.”
As for hatchlings, they often get blocked, or completely stopped, by litter, man-made holes, and even footprints. Light pollution can make them travel in the wrong direction.
“If you think about it in a world without humans, the only lights are going to be moonlight reflecting off the water, and so the hatchlings are evolutionary primed and geared towards crawling down the beach … toward the moonlight on the water,” said Kyle Van Houtan, turtle expert and chief scientist at the Monterey Bay Aquarium. “But if there’s a bunch of development and hotels and cities with all sorts of light, they could draw the turtles inland where they get run over or picked up by birds.”
COVID-19 lockdowns could provide short-term benefits for nesting mothers and their hatchlings, but Perrault said he doesn’t expect the pandemic to make a significant impact on turtle populations in the long term.
“Sea turtles are a long-lived and highly migratory species, so a temporary shut down only provides sea turtles a healthy break from some human-related disturbances, and we do not expect many long-term benefits to population recovery due to this short shutdown,” Perrault said. “The hope for survival comes from continued vigilance of local beach-goers and local, national, and international protections for these imperiled species.”
In Phuket, Kanokwan Homcha-aim, supervisor of Maikhao Marine Turtle Foundation, a local group that educates the community about turtle conservation, told Mongabay the return of the leatherbacks “is not related to the lockdown” since they were already nesting before the pandemic hit.
According to Van Houtan, a bumper nesting season tends to be influenced more by the availability of food and the ability of female sea turtles to get enough nutrition to produce eggs.
“Female sea turtles don’t nest every year; they nest every three to seven years, depending on the excess amount of calories that they have,” he told Mongabay. “Their parenting essentially goes into the yolk which makes those eggs, and they’re only going to do that if they have the excess calories and the metabolic energy to allocate to that, and that means that they’ve been eating a lot and the place where they forage has been producing enough food. And this is something that is months in making … and so this is reflecting something that happened before the pandemic.”
If the pandemic does yield any benefits for sea turtles, Godfrey says it will take a long time to see.
“It’s possible that some additional hatchlings will survive this year that otherwise might have died,” Godfrey told Mongabay. “In short, we may see increased survivorship of nests this year. However, given that it takes about 30 years for hatchlings to mature and nest themselves, by the time we get three decades down the road it will be impossible to ever determine if a change in nesting rates was due to the pandemic. Too many variables at play that far in the future.”
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May 23, 2020 at 04:22AM
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Slow and steady: Sea turtles mount a long-term recovery - Mongabay.com
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