Published April 14, 2015
Against the odds, seven species of sea turtle have withstood the test of time and captured the hearts of humans, but they could soon be ancient history without our help.
Earth was a different place 150 million years ago. The continents were drifting, the earliest flowers were just beginning to evolve and dinosaurs roamed the land. Few plants and animals from this period would endure the catastrophic events to come.
But what survives that which the dinosaurs cannot? As it turns out, one of Earth’s most long-lived creatures isn’t the fearsome predator you might imagine. We’re talking about the sea turtle, a beloved marine marvel whose tenacity would have made Darwin proud.
These prehistoric reptiles face overwhelming odds from the get-go, with only five out of 100 making it through their first day in existence. After hatching, they emerge from their sand-covered nests to make a run for the waves. Our beaches are their battlefields, laden with enemies occupying land, air and sea. If the hatchlings evade the beach’s birds and crabs, they begin round two—this time against the predatory fish and seabirds combing the water’s surface for snacks.
The lucky ones that escape an early fate will likely go on to live long lives—sometimes 60 years or more. Like salmon, the females eventually return to the same nesting grounds where they were born, laying up to 12 nests—with about 100 eggs each—per season.
While hatchlings face countless risks, adult sea turtles managed to get on Mother Nature’s good side. Other than the occasional shark attack, they’re relatively immune to predation. But this coveted place on the food chain doesn’t come without responsibilities.
In reef habitats, for example, coral and sponge species are always competing for dominance. Thankfully, coral has an ally in the hawksbill sea turtle. These guys feed on a few predominate sponge species, keeping their numbers in check and giving coral the upper hand.
Sea turtles also help maintain healthy prey populations. Jellies, for instance, are the choice cuisine of many marine turtle species. This includes the giant leatherback, which can down more than 440 pounds of jellies in a single day. To put things in perspective: That’s nearly the weight of a full-grown pig.
Now imagine what happens when that insatiable species disappears. Seafood lovers of the world, be warned: This could spell trouble for your favorite aquatic cuisine. With the help of overfishing and a lack of predators, these gelatinous opportunists could have significant environmental and economic implications in the future.
Canaries in a Coal Mine
The sad reality is that we’re fast approaching a world without sea turtles. After relentlessly persevering through 150 million years of evolutionary hurdles, these incredible animals have finally hit a snag that could end their streak—and it’s not because of birds, crabs, fish or other natural threats. It’s because of us.
Today, six out of the seven sea turtle species are endangered or threatened. No. 7, the flatback, is simply listed by the IUCN Red List of Threatened Species as “data-deficient.” There’s a term for statistics like that: a red flag. An indicator of a larger problem. So what destroys what should be indestructible?
Dedicated sea turtle researchers have some answers. Entanglement in commercial fishing gear takes the cake for deadliest threat facing these resilient reptiles. Hundreds of thousands of turtles are accidentally caught in shrimp trawl nets, on longline hooks and in fishing gillnets each year. Those that don’t escape drown, unable to return to the water’s surface for air.
Some of the survivors are repeat offenders. With the help of satellite tagging, National Aquarium Animal Rescue Manager Jenn Dittmar has noticed the same turtles returning to the same nets. “They’ve unfortunately learned that if they get into the nets, it’s a seafood buffet for them,” she says.
Commercial fishing isn’t the only culprit. Recreational fishing can affect these populations as well. “We’re seeing an increase in the number being hooked by recreational fishing line,” she explains. “We’ll see turtles that have swallowed hooks when they come in.”
Other threats are more deliberate. Outside of the United States, tens of thousands of endangered sea turtles are being hunted every year for their eggs, meat, skin and shells. Even one of the National Aquarium Animal Rescue’s rehabilitated patients was taken for food after its release into the ocean. Dittmar knew something wasn’t right when she noticed its satellite tag suddenly transmitting from Honduras after a slow and steady migration south. Contacts in Costa Rica followed up and confirmed her suspicions: A local fishing village had the tag.
Illegal trade has also played a role in dwindling sea turtle populations. In fact, it’s the biggest threat to hawksbills, which are prized for their beautiful brown and yellow carapace plates. These stunning turtle shells are used to create jewelry, ornaments and other souvenirs.
Lastly, sea turtles don’t have the habitat they once had. The beaches they require for nesting grounds have been destroyed and disturbed by coastal development, vehicle traffic and other human activity, including armoring beaches with rock sea walls to prevent erosion. Pollution has infiltrated the waters they call home, throwing new risks into the mix. Leatherback sea turtles, for example, commonly mistake floating plastic bags for tasty jellyfish, resulting in a potentially deadly meal.
Fixing the Future
Part of the problem lies in the lack of international protection. Sea turtles travel great distances in the course of a year. “A female leatherback sea turtle may be laying eggs on a French Guianan beach at one point in the year; be swimming off of Ocean City, Maryland, at another time of year; and feeding on jellyfish in the chilly waters off of Nova Scotia at another time of year,” Cover says. It will take international conservation efforts to change the fate of these critical species, giving them a chance to thrive once again.
The good news is there’s still time to make that happen.