Mind sets are shifting on the remote island of Príncipe, where communities are joining the fight to protect sea turtles. Sea turtles have become a global symbol in the war against plastic. The effect of single-use plastic in the ocean is felt by all seven species of sea turtle, even in the remotest parts of the planet. One of these far-flung locations is the Chocolate Isles of São Tomé and Príncipe, off Africa’s west coast.
Sea turtles gather in this tropical paradise to breed. In 2018, 30% of the recorded sea turtle deaths on Príncipe were a result of plastic – a significant increase from the previous three years of monitoring. With a population of only 7 000 people, Príncipe is focused on sustainability, but as long as other countries continue to use plastic the implications will be felt everywhere.
“In the 2017/2018 breeding season we saw a new record number of nests on our beaches,” says Vanessa Schmitt, project coordinator of The Príncipe Trust’s Marine Turtle Protection and Conservation Project, ProTetuga.
The ProTetuga team recorded 2 103 nests scattered across more than 28 beaches. “This figure is an outlier. In the 2016/17 nesting season we only had 743 nests, and we have not seen the same number in the 2018/19 breeding season,” warns Schmitt.
Green turtle nests made up the majority of this figure, laying are record number of 2 050 nests. While
45 hawksbill nests were recorded, this figure remains consistent with previous years. Only eight leatherback nests were recorded, showing a 50% decline. The olive ridley sea turtle is also known to nest in São Tomé. The majority of the sea turtle nests (55%) were on Praia Grande, the largest and most popular turtling beach on the island, while 30% of the nests were located on Praia Infante. “Praia Infante, located to the south of the island, is more isolated, so the nests are less vulnerable. Increased breeding here may contribute to future population growth,” explains Schmitt. “ProTetuga focuses on three main pillars: protection and monitoring; education and awareness; and research,” she says.
Protecting and monitoring sea turtles on Príncipe
Communities living on São Tomé and Príncipe lack a sufficient protein source and are reliant on marine resources for food. Although on the decline, turtles form an important part of their diet. The estimated number of illegal catches has reduced by 50% compared to previous turtle seasons. “Nesting female turtles are increasingly vulnerable to capture,” explains Vanessa Schmitt. Conservation efforts also received a
boost in 2014 with the publication of a national law prohibiting the capture, sale, and consumption of sea turtle meat throughout the country.” In the ocean, both juveniles and adults are captured for meat. Fishermen often dive to catch fish, octopus, and turtles, making it hard to find traces of dead turtles. “We had 14 cases of turtles captured for meat, but these are only the ones we found,” says Schmitt.
Kaxí Tetuga Museum: sea turtle education and awareness
The Kaxí Tetuga Museum on Praia Grande is the only institute of marine biodiversity on the Island. “During the 2017/2018 turtling season €8 735 was raised for the community fund,” says Schmitt. “It’s important for Príncipeans to see more value in a living turtle than a dead one.” The Kaxí Tetuga Museum also focuses on marine education among local school children and gives children the opportunity to see the hatching process first-hand.
After braving crabs and seabirds on the beach the hatchlings enter the pelagic part of their life phase, meaning they roam the open oceans. During this period they are generalist feeders. Only one in 100 sea turtles survive into adulthood.
ProTetuga sea turtle research
Of the seven sea turtle species, each has a role to play in ocean ecology. The leatherback keeps jellyfish populations in check. The hawksbill, being a spongivore, helps maintain the delicate equilibrium between sponges and corals that compete on the reef. Green turtles mow seagrass beds and clip mangrove shoots, keeping the beach clear of encroaching vegetation. Turtles are also believed to play a crucial role in
the dispersal of epibionts, often acting as barnacle buses.
Green sea turtles in Príncipe
Much like islanders around the world, sailors also relied on turtle meat for protein. The green turtle (Chelonia mydas) got its name from its jade-coloured fat. The green turtles are the second-largest sea turtle and the slowest growing. The green turtle is the most commonly seen turtle in São Tomé and Príncipe, therefore it was chosen for the Arribada Initiative, a tagging project aiming to develop affordable conservation technologies that allow humans to venture into the secret world of wildlife.
“To date, we have tagged about 20 turtles,” says Alasdair Davies, founder of the Arribada Initiative. “We selected green turtles as they were numerous and also a good size to work with. Hawksbills are smaller and require a smaller tag, and you can’t tag leatherbacks using epoxy solution to attach the tag to their skin.” Unlike other sea turtles, leatherbacks do not have a shell. They are also not common in the area.
From this project, researchers were able to determine that breeding green turtles fed on algae in the absence of seagrass beds. “Breeding green turtles use Praia Grande as a safe location to rest between laying cycles,” explains Davies. “Using the GPS data we can better protect their nesting grounds and inform fishermen as to when and where they should be aware of turtles to avoid boat crashes.”
Green sea turtle facts
- Average age: 80 years.
- Diet: Primarily vegetarian, feeding on seagrass, algae and mangrove shoots.
- Eggs: Females breed every two to four years, laying three to five clutches of between 85 and 200 eggs per season.
- Status: Endangered.
Hawksbill sea turtles
The hawksbill turtle (Eretmochelys imbricata) resides on coral reefs in tropical waters worldwide. It has a
parrot-like beak and is often seen in the presence of angelfish, another spongivore. Hawksbills maintain defined territories on the reef and will migrate miles to their natal beach. They can migrate miles from the feeding grounds to breed and then return again. The hawksbill is targeted by São Toméans for its shell, which is used to make crafts.
Hawksbill sea turtle facts
- Lifespan: 30 to 50 years.
- Diet: Omnivores with a preference for sponges.
- Eggs: Females breed every two to three years, laying three to six clutches of 160 eggs per season.
- Status: Critically endangered.
Leatherback sea turtles
The leatherback (Dermochelys coriacea), often regarded as a living fossil, is an ocean-faring heavyweight; a fully grown adult can clock in at almost a ton. The leatherback is capable of diving to depths frequented by sperm whales while feeding in the deep scattering layer. It is able to hold its breath for 85 minutes.
Its mouth is a terrifying one-way tract lined with scary-looking papillae that make it immune to jellyfish stings. Because of this, when it starts to ingest plastic, it is unable to spit it out. Adult leatherbacks roam the ocean freely searching for food, making their way to warmer areas like the Chocolate Isles to breed every few years. It is still uncertain as to why leatherback populations have declined in Príncipe. The leatherback has the widest distribution of turtles and has been known to appear as far north as Norway. They are also less loyal to their natal beach and will flirt with other suitable nesting locations.
Leatherback sea turtle facts
- Age: 30 to 50 years.
- Diet: Jellyfish, sea jellies and soft body organisms.
- Eggs: Females breed every three years, producing nine clutches of 110 eggs each in a season.
- Status: Vulnerable
Turtling on Príncipe
Guests can arrange to go turtling via the four hotels on the island: Bom Bom, Sundy Praia, Roça Sundy and Hotel Roça Belo Monte. Turtle tours take place on Praia Grande and are led by trained guides. Space is limited and tours cost around €35 per person. Turtle season on Príncipe is from September to March, with tours operating from November onwards.
Written by: Georgina Lockwood
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