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Endangered green turtles bounce back on Seychelles beaches

6 min read

Inspiring People
Endangered green turtles bounce back on Seychelles beaches
Source: Unsplash/

After several decades of protection and monitoring, the endangered green turtle is making a comeback to the Seychelles’ Aldabra Atoll. More than 15,000 annual clutches are now appearing, up from 3,000 in the 1960s.

Endangered green turtle numbers up sixfold in Seychelles

A new study shows that after half a century of protection, green turtle numbers have only continued to climb in the Seychelles’ Aldabra Atoll. Published in Endangered Species Research, the study found that the annual number of green turtle clutches increased from the 2,000 to 3,000 range in the late 1960s, to more than 15,000 in the late 2010s—a sixfold increase. 

However, records from the early 1900s show that as many as 12,000 turtles were allowed to be taken from Aldabra each year, he says, suggesting that the nesting population then was even higher. Image: Martin van Royen courtesy Seychelles Islands Foundation.
Based on the number of clutches, he estimates that there are about 3,000 to 5,000 female green turtles nesting on Aldabra today. However, records from the early 1900s show that as many as 12,000 turtles were allowed to be taken from Aldabra each year, he says, suggesting that the nesting population then was even higher. Image: Martin van Royen courtesy Seychelles Islands Foundation. Source: popsci.com
Seagrass consumed by green turtles is quickly digested and becomes available as recycled nutrients to the many species of plants and animals that live in the sea grass ecosystem. Seagrass beds also function as nurseries for several species of invertebrates and fish, many of which are of considerable value to commercial fisheries and therefore important to human food security. © Jürgen Freund / WWF-Canon
Green turtles graze on seagrasses and algae, which maintains the seagrass beds and makes them more productive (much like mowing the lawn to keep it healthy). Seagrass consumed by green turtles is quickly digested and becomes available as recycled nutrients to the many species of plants and animals that live in the sea grass ecosystem. Seagrass beds also function as nurseries for several species of invertebrates and fish, many of which are of considerable value to commercial fisheries and therefore important to human food security. © Jürgen Freund / WWF-Canon Source: © Jürgen Freund/WWF

reason for hope for the world’s largest green turtle population

Green turtles, the only herbivore and one of the largest among sea turtles, nest in more than 80 countries and live in coastal areas throughout the world. Their populations have suffered drastic declines historically as a result of human exploitation for their fat, meat, and eggs. Today, the global population of the endangered species is still in decline.

But in Aldabra, home to one of the world’s largest green turtle populations, there is reason for hope. The population on this coral atoll still has plenty of room to grow, lead author Adam Pritchard from the University of Exeter told Popular Science. 

Based on the number of clutches, he estimates that there are about 3,000 to 5,000 female green turtles nesting on Aldabra today. However, records from the early 1900s show that as many as 12,000 turtles were allowed to be taken from Aldabra each year, he says, suggesting that the nesting population then was even higher.

“The fact that we’re at around 3,000 to 5,000 now, which is already so much more than there were in the 1960s, implies that there’s potential for this population to double, triple—we’re not even sure,” Pritchard says. “This could just be the start. It’s amazing that, after slower growth at the beginning, there’s been this real explosion in recent years.”

Source: PopularScience 

Uncontrolled coastal development, vehicle traffic on beaches, and other human activities have directly destroyed or disturbed sea turtle nesting beaches around the world. Green turtle feeding grounds such as seagrass beds are also at risk from coastal development onshore, which leads to pollution and sedimentation in the nearby waters. © Roger Hooper / WWF-Canon
Sea turtles are dependent on beaches for nesting. Uncontrolled coastal development, vehicle traffic on beaches, and other human activities have directly destroyed or disturbed sea turtle nesting beaches around the world. Green turtle feeding grounds such as seagrass beds are also at risk from coastal development onshore, which leads to pollution and sedimentation in the nearby waters. © Roger Hooper / WWF-Canon Source: © Roger Hooper / WWF
In the Eastern Pacific, a group of green turtles that have darker shells are called black turtles by the local community. Green turtles are found mainly in tropical and subtropical waters. Like other sea turtles, they migrate long distances between feeding grounds and the beaches from where they hatched. Classified as endangered, green turtles are threatened by over harvesting of their eggs, hunting of adults, being caught in fishing gear and loss of nesting beach sites.
The green turtle is one of the largest sea turtles and the only herbivore among the different species. Green turtles are in fact named for the greenish color of their cartilage and fat, not their shells. In the Eastern Pacific, a group of green turtles that have darker shells are called black turtles by the local community. Green turtles are found mainly in tropical and subtropical waters. Like other sea turtles, they migrate long distances between feeding grounds and the beaches from where they hatched. Classified as endangered, green turtles are threatened by over harvesting of their eggs, hunting of adults, being caught in fishing gear and loss of nesting beach sites. Source: Unsplash/Roberto Lopez

long-term data is crucial since conservation work will not show instant results

The success of green turtle conservation in Aldabra is a testament to the importance of long-term protection. The turtles seem to have not only benefited from the hunting ban in 1968, but also Aldabra’s designation as a UNESCO Heritage Site in 1982. Located in the Indian Ocean off East Africa, Aldabra is a coral atoll that is part of the Seychelles, an archipelago of 115 islands. The remoteness and inaccessibility of Aldabra has allowed it to remain largely untouched by humans for the majority of its existence.

“It could’ve gone the other way so easily if people had made some other decision to not protect Aldabra,” says co-author Cheryl Sanchez from the Seychelles Island Foundation (SIF). “That would’ve been it, if it weren’t for people’s foresight and these incredible Seychellois leaders who are proud of their natural resources and want to protect them.”

What’s equally important is the dedication and patience required to sustain long-term monitoring. For a species like the green turtle, which takes at least 20 to 50 years to reach sexual maturity and reproduce, long-term data is crucial since conservation work will not show instant results. If it weren’t for the hundreds of people who gathered decades of data across Aldabra’s more than 50 beaches, it would have been difficult to track the progress made in turtle conservation, Pritchard says.

Source: PopularScience

If it weren’t for the hundreds of people who gathered decades of data across Aldabra’s more than 50 beaches, it would have been difficult to track the progress made in turtle conservation.
For a species like the green turtle, which takes at least 20 to 50 years to reach sexual maturity and reproduce, long-term data is crucial since conservation work will not show instant results. If it weren’t for the hundreds of people who gathered decades of data across Aldabra’s more than 50 beaches, it would have been difficult to track the progress made in turtle conservation. Source: Unsplash/Bruce Warrington
Instead of killing a turtle to sell its body parts, the country could now use the species to attract tourism, a much more sustainable and low-impact source of profit.
The Seychelles government made the decision to ban turtle hunting in 1968 and start protecting the endangered species. Instead of killing a turtle to sell its body parts, the country could now use the species to attract tourism, a much more sustainable and low-impact source of profit. Source: Unsplash/Filipe Silvia

There is much to learn from Aldabra

After realising that Aldabra’s turtle would cease to exist if nothing was done, the Seychelles government made the decision to ban turtle hunting in 1968 and start protecting the endangered species. Instead of killing a turtle to sell its body parts, the country could now use the species to attract tourism, a much more sustainable and low-impact source of profit.

The annual team of less than 20 people on Aldabra monitor not just sea turtles, but also giant tortoises, frigatebirds, rainfall, and more. Sanchez, who has contributed to SIF’s work on Aldabra, emphasises the amount of effort that goes into the data collection process. 

The small team visits sites all over the massive atoll by boat, while navigating extreme tides and rough weather. The fact that people have maintained this monitoring program for so long is astounding, Sanchez says, and sets an example for what can be done elsewhere if it can be done in an environment as tough as Aldabra.

There’s also much to learn from Aldabra in terms of how to successfully restore a turtle population. Aldabra’s green turtle restoration is not the only win for the species in recent years. Similar recoveries have been recorded in the US, Costa Rica, and Ascension Island to name a few. And in each of these cases, a common message rings clear: If we protect the beaches, the turtles can handle the rest. They will recover. 

Source: PopularScience

They will recover.
If we protect the beaches, the turtles can handle the rest. They will recover. Source: Unsplash/Marco Bicca
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