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Turtles in the Cape Verdes

Loggerhead turtles in Boa Vista

Four species of turtle breed on Boa Vista and these can be seen coming ashore at night to lay eggs, at certain times of year. Boa Vista has one of the largest turtle breeding grounds in the world for loggerhead, hawksbill, leatherback and green turtles. They land in summer to breed.The vast marine turtles site at Ervatao beach on sparsely populated Boa Vista was discovered quite recently. It is the world's third most important loggerhead nesting site. Environmentalists fear that Cape Verde's growing tourism industry will wipe out also this nesting site. Slowly dragging its shell onto the beach, a turtle emerges from the ocean. It is midnight and the moon is casting its shadow over the remote, white-sandy coastline of Boa Vista. The slow turtle, if not disturbed, will make a nest for more than 40 whitish, golf ball-sized eggs and return to the ocean. Every year, from late May to September, more than 3,000 loggerhead turtles (Caretta caretta) come ashore to Cape Verde's beaches, particularly at Ervatao beach, the third most important loggerhead nesting site in the world after Oman's Massirah Island and the Florida Keys. Amazingly enough, the Boa Vista site was discovered only a few years ago.

"Marine turtles have been wiped out on almost all of the other Cape Verde islands, but they have thrived so far on Boa Vista where human predation and pressure is lower,"
Dr Luis Felipe Lopez, a 64 year-old Spanish biology professor from Las Palmas University,in the Canaries told the environmentalist group WWF. Mr Lopez is leading a local conservation group, Natura 2000, to protect the turtles' nesting habitat at Ervatao. With only 4,200 people living on the 620 km2 island - mostly inhabiting the small town of Sal Rei and a few neighbouring villages - Boa Vista is one of the archipelago's most pristine islands.
"But for how long?"
environmentalists ask. Ironically, the island's biggest threat - and by extension a threat to the turtles - may come from the unspoiled coastline itself. With 50 km of beautiful, uninhabited beaches, the island is likely to become a magnet for sun-seekers, especially if the Government's plans to develop the area for tourism proceed.

Their journeys are among the longest in the animal kingdom and they have largely remained a mystery until now. An international team of scientists has uncovered the migratory secrets of endangered loggerhead turtles in West Africa and the results could have huge implications for strategies to protect them. In a paper in the journal Current Biology, Drs. Brendan Godley and Michael Coyne and an international team describe how they used satellite tracking systems to follow the journeys of ten turtles from Boa Vista, which is one of the world's largest nesting sites for loggerheads and also a hotspot for industrial fishing. What they found could turn current conservation strategies upside down, as the team discovered the turtles adopted two distinct approaches to finding food, linked to their size. Previously it was thought that hatchlings left the coastal region to forage far out at sea before returning, later in life, to find food closer to shore. However the new findings show that the oceanic habitats contained far larger animals than was previously thought. The team tracked the turtles as they left nesting sites, following them for up to two years over ranges that covered more than half a million square kilometres.

Dr Brendan Godley, of the University of Exeter, said:

"We were surprised to find such large turtles looking for food out in the open ocean, as it was previously thought that animals of this size would have moved back to forage in coastal zones. This means there are much greater numbers of the breeding population out at sea and far more that are vulnerable to the intensive long-line fishing effort that occurs in that region."

Dr Michael Coyne, Director of SEATURTLE.org and a research scientist at Duke University, added:

"From the information collected, we have been able to determine how much time these animals are spending within the sovereign boundaries of each country in the region. This research highlights how complicated the migration of marine vertebrates really is and how sophisticated our conservation efforts must be to safeguard these animals. Given the range these reptiles can cover an international cooperative effort in seven African states is needed to create a strategy that would protect them."

Research* shows that in 2000 1.4 billion hooks were cast into the world's oceans through industrial fishing. It's thought that more than 200,000 loggerhead turtles were incidentally caught by fisherman around the world scouring the waters for other species such as tuna and swordfish. Of these, tens of thousands are thought to die as a result. 37% of this fishing effort was in the Atlantic and a major hotspot for fishing is found off West Africa, the region where the Cape Verdean turtles reside. In recent years marine turtle researchers have been using satellite telemetry to track turtle migrations. Satellite transmitter tags are attached to the shell of the turtle so that every time the turtle surfaces to breathe, the tag transmits the turtle's position, as well as other information (e.g. depth and duration of dives), to satellites orbiting above, which then relay the data by e-mail to the computer of the scientist who attached the tag. Full article is available at Current Biology:

It is estimated that no more than 300 tourists currently visit the turtle breeding beaches on Boa Vista annually. University of Algarve at Faro is studying turtle nesting on Santiago beaches.

"Sea turtles are an integral part of the natural heritage of Cape Verde and historical evidence of their consumptive use by people dates back to the 15th Century. One record from Alvise da Ca’ da Mosto (1507), probably one of first Europeans that arrived to the Boavista and Santiago Islands, in 1456, states that: “we found a large number of sea turtles, whose carapaces were bigger than military leather shields, and we killed many and cooked...; finally, we salted a lot of them, that we carried into the ship to eat later”. Another report from Valenty Fernandez (Monod et al. 1951): “During the months of May June July and August there is in these islands a great abundance of sea turtles that help one recover from the leprosy illness.” Santiago Island, the largest in Cape Verde, was the first island to be settled, and the population of turtles nesting on the beaches of Santiago and in the near shore waters likely experienced high levels of human predation. Four species of sea turtles occur in and around Santiago Island, Cape Verde. The loggerhead (Caretta caretta) is the only species that has been confirmed nesting and is also encountered in coastal waters. The green turtle (Chelonia mydas) is present in the waters of Santiago, but only as juveniles. Some are captured incidentally in fisheries, and there are a few anecdotal reports of fishermen directly targeting green turtles for food, although their small size (25 to 40 cm CCL) makes them less appealing than large juveniles or adults. The leatherback (Dermochelys coriacea) is rarely sighted in the waters of Santiago, although interviews with elderly fishers suggest that they were more abundant in the past. The hawksbill (Eretmochelys imbricata) is also rare, and only records of juveniles have been reported from the waters of Santiago. Since 2002, all sea turtles and their habitats are protected by law (Decreto-Regulamentar n° 7/2002), but the consumption of sea turtle meat and eggs has not significantly decreased. National authorities are increasing their efforts to reduce sea turtle captures."