Sea Turtle Comeback

It’s a warm night on a beach in Central Mexico. Dozens of scientists and locals are gathered along the shore. They trudge through the sand, scanning the dark waves. Suddenly, someone spots movement in the water: It’s a green sea turtle!

Each year, thousands of female green sea turtles return to this beach—the same one where they were born—to dig nests and lay their eggs (see “A Sea Turtle’s Life,”, below). And when they arrive, conservationists are waiting to protect the animals—and their eggs—from predators and humans looking to harm them. “We’re protecting them because that’s what you do when you love something,” says Bryan Wallace. He’s a wildlife biologist at Ecolibrium, an environmental organization that supports sea turtle recovery efforts in Mexico and Central America.

With their brown-scaled flippers and intricately patterned shell, green sea turtles are iconic marine animals. You may recognize them as the inspiration for the character Crush in the movie Finding Nemo. Green sea turtles were once abundant in tropical waters around the globe. But hunting, fishing, and habitat loss caused their populations to plummet. By the 1970s, green sea turtles were declared endangered—or on track to disappear completely.

But that is no longer the case. This past October, the International Union for the Conservation of Nature (IUCN) announced that it was taking green sea turtles off its endangered list. Thanks to decades of conservation efforts, the species is officially on the rebound!

It’s a warm night on a beach in central Mexico. Dozens of scientists and locals gather along the shore. They plod through the sand as they scan the dark waves. Then someone spots movement in the water. It’s a green sea turtle!

Each year, thousands of female green sea turtles come to this beach. They were born here. Now they return to dig nests and lay their eggs (see “A Sea Turtle’s Life”). And when they arrive, conservationists are waiting. They protect the animals and their eggs so predators and people don’t harm them. “We’re protecting them because that’s what you do when you love something,” says Bryan Wallace. He’s a wildlife biologist at Ecolibrium. This environmental organization supports sea turtle recovery efforts in Mexico and Central America.

Green sea turtles are well-known marine animals. They have brown-scaled flippers and shells with detailed patterns. You may recognize them from the movie Finding Nemo. They inspired the character Crush. In the past, green sea turtles were abundant in tropical waters around the globe. But their populations plummeted because of hunting, fishing, and habitat loss. By the 1970s, green sea turtles were declared endangered. They were on track to disappear completely.

But that is no longer true. This past October, the International Union for the Conservation of Nature (IUCN) took green sea turtles off its endangered list. Decades of conservation efforts have paid off. The species is officially on the rebound!

Centuries ago, tens of millions of green sea turtles filled the seas. There were so many of these creatures that, on dark nights, European sailors would navigate unfamiliar waters by listening for the thud of turtle shells against their wooden boats and the little gasps of turtles surfacing for air. “That’s how explorers in the 1500s knew they were nearing land,” says Wallace. “The closer they got to an island, the more sea turtles there would be grazing for food and nesting.”

Green sea turtles have long played an important role in ocean ecosystems—communities of organisms interacting with each other and their physical surroundings. “We like to call them the lawn mowers of the sea,” says Josefa Muñoz, a graduate student researching sea turtles at the Hawaii Institute of Marine Biology. Adult green sea turtles are herbivores, or plant eaters. They keep coral reefs and underwater meadows healthy by munching on algae and seagrass. The animals are also an important spiritual symbol for many Indigenous cultures.

As European colonists spread across the world in the 16th to 19th centuries, they began hunting sea turtles and harvesting their eggs. Green sea turtles were hit especially hard, since this species was prized for its meat. Colonists “could take 50 sea turtles off a beach on a given night and do it again the next night,” says Wallace. “The supply of sea turtles seemed endless.”

Centuries ago, tens of millions of green sea turtles filled the seas. Because these creatures were so numerous, their sounds helped European sailors navigate unfamiliar waters. On dark nights, the sailors listened. Turtle shells thudded against their wooden boats. And turtles made little gasps when they surfaced for air. “That’s how explorers in the 1500s knew they were nearing land,” says Wallace. “The closer they got to an island, the more sea turtles there would be grazing for food and nesting.”

Green sea turtles have long been important to ocean ecosystems. These are communities of organisms that interact with each other and their surroundings. Josefa Muñoz is a graduate student who researches sea turtles at the Hawaii Institute of Marine Biology. “We like to call them the lawn mowers of the sea,” she says. Adult green sea turtles are herbivores. These plant eaters munch on algae and seagrass. That keeps coral reefs and underwater meadows healthy. The animals are also an important spiritual symbol for many Indigenous cultures.

In the 16th to 19th centuries, European colonists spread across the world. They hunted sea turtles and harvested their eggs. Green sea turtles were hit especially hard because they were prized for their meat. Colonists “could take 50 sea turtles off a beach on a given night and do it again the next night,” says Wallace. “The supply of sea turtles seemed endless.”

By the 1950s, up to two-thirds of the world’s green sea turtles were gone. Scientists estimate that in some places, like Florida, popula- tions had declined by more than 90 percent. And hunting was no longer the only threat. Turtles frequently ended up as bycatch—animals caught accidentally in the nets of commercial fishing boats. Plus, green sea turtles were losing critical habitat as people constructed roads, housing developments, and resorts on beaches where the animals built their nests.

Scientists and policymakers began to sound the alarm. If something wasn’t done, green sea turtles would not exist much longer. The solution would require an international collaboration between governments, scientists, and the communities living alongside turtles.

The first major step happened in 1973, when 21 countries agreed to ban the trade of endangered wild plants and animals, including sea turtles. This agreement has since expanded to include 184 countries. Policies like this one have played an important role in helping hundreds of endangered species make a comeback (see“Back From the Brink,” below).

Countries like the United States, Canada, and Mexico also began working together to limit fishing practices that harm sea turtles. Many nations passed laws protecting sea turtle habitat and banning the sale of sea turtle shells, meat, and eggs. “With those protections, baby turtles were allowed to grow older, adults were allowed to breed, and gradually, populations began to increase,” says Brendan Godley, a conservation scientist at the University of Exeter in the United Kingdom.

By the 1950s, up to two-thirds of the world’s green sea turtles were gone. Losses were greater in some places, like Florida. Scientists estimate that populations dropped by more than 90 percent there. Hunting was no longer the only threat. Turtles often ended up as bycatch. They were caught accidentally in the nets of commercial fishing boats. And green sea turtles were losing important habitat. People constructed roads, housing developments, and resorts on beaches. That’s where the animals built their nests.

Scientists and policymakers sounded the alarm. If something wasn’t done, green sea turtles would disappear. The solution would require international teamwork. Governments, scientists, and communities near turtles needed to work together.

The first major step happened in 1973. Twenty-one countries agreed to ban the trade of endangered wild plants and animals. That included sea turtles. This agreement has expanded to include 184 countries. Policies like this one have helped hundreds of endangered species make a comeback (see “Back From the Brink”).

Countries like the United States, Canada, and Mexico also worked together. They limited fishing practices that harm sea turtles. Many nations passed laws to protect sea turtle habitat. And they banned the sale of sea turtle shells, meat, and eggs. “With those protections, baby turtles were allowed to grow older, adults were allowed to breed, and gradually, populations began to increase,” says Brendan Godley. He’s a conservation scientist at the University of Exeter in the United Kingdom.

When it comes to saving green sea turtles, some of the most impactful efforts are happening on beaches where scientists and community members keep an eye out for nesting turtles, says Wallace. These beach patrollers have two goals: to study the animals and to make sure mother and baby sea turtles can safely complete their journey back to the sea.

Community members stay up all night guarding nests from people trying to illegally harvest the eggs. Sometimes a female sea turtle will lay her eggs too close to predators, foot traffic, or the ocean. The patrollers will collect the eggs and bring them to a hatchery where they can be incubated—or be kept warm—out of harm’s way. Once the babies hatch, community members release them on the beach and watch them race to the ocean. “There are thousands of people at hundreds of sites doing this kind of work,” says Wallace.

Wallace has seen the results of these efforts firsthand. At many of the sites he visits, more and more green sea turtles are returning each year. In fact, green sea turtle populations have increased by nearly 30 percent since the 1970s. At some beaches, populations have returned to levels people haven’t seen since the arrival of European colonists. This hard work must continue if we want to keep green sea turtles off the endangered species list, says Wallace. Threats to sea turtles haven’t completely disappeared, and green sea turtle populations are still threatened in many parts of the world. “We’re seeing green sea turtles recover thanks to this collective action,” says Wallace. “But the job isn’t finished yet.”

On beaches, scientists and community members watch out for nesting turtles. These are some of the most effective efforts for saving green sea turtles, says Wallace. The beach patrollers have two goals. They want to study the animals. And they make sure mother and baby sea turtles can safely complete their journey back to the sea.

People try to illegally harvest the eggs. So community members stay up all night to guard the nests. Sometimes a female sea turtle will lay her eggs too close to predators, foot traffic, or the ocean. The patrollers will collect the eggs and bring them to a hatchery. There, the eggs can be safely incubated, or kept warm. When the babies hatch, community members release them on the beach. Then they watch them race to the ocean. “There are thousands of people at hundreds of sites doing this kind of work,” says Wallace.

Wallace sees the results of these efforts firsthand. He visits turtle nesting sites. At many of them, more and more green sea turtles are returning each year. In fact, green sea turtle populations have grown nearly 30 percent since the 1970s. Some beaches now have as many turtles as when European colonists arrived. To keep green sea turtles off the endangered species list, this hard work must continue, says Wallace. Threats to sea turtles aren’t completely gone. And green sea turtle populations are still threatened in many parts of the world. “We’re seeing green sea turtles recover thanks to this collective action,” says Wallace. “But the job isn’t finished yet.”