Sea turtles of Guinea-Bissau

Guinea-Bissau is of global importance for the conservation of sea turtles, hosting one of the world's largest populations of green turtle. Olive ridleys, hawksbills and leatherbacks also nest in the sandy beaches of the Bijagós, and important developmental grounds exist for juvenile green turtles. The illegal harvesting of turtles and their eggs, bycatch by industrial and artisanal fishing vessels, and the decline in surface and quality of nesting habitat due to coastal erosion, flooding, unregulated tourism practices, and predation by invasive species are the main threats.

Green turtle, Chelonia mydas

Distribution in Guinea-Bissau

In Guinea-Bissau, green turtles nest mostly in the islands of the Bijagós Archipelago, with recent nesting confirmed in Formosa, Caravela, Unhocomo, Unhocomozinho, Orango, Bubaque, Canhabaque, Bubaque, João Vieira, Meio, Cavalos, Poilão and Cabras. Nesting also occurs in some sites of the mainland coast; Cape Roxo, Varela area and the islands of Jeta and Pecixe in the north, and the island of Melo in the south. Most of the nesting is concentrated on the islands of the Marine National Park of João Vieira Poilão, with probably over 90% of the clutches laid at a single small island, Poilão. This island alone hosts one of the largest green turtle populations worldwide, with a mean of 25,000 clutches laid anually. Foraging juveniles and adults are also common in the coastal waters of the Bijagós archipelago, Bolama Island and Varela.

Breeding season

In Guinea-Bissau, the green turtles breed mostly during the rainy season, from June to December, with a peak in July, August and September, however, nesting can occur throughout the year, with lower numbers between April and May. Most of the hatching happens in October and November, when the beach at Poilão gets filled with crawling baby turtles!

Name in Krioul: Tataruga preto

Name in Bijagós: Etchunko

Olive ridley, Lepidochelys olivacea

Distribution in Guinea-Bissau

The most important site for olive ridley nesting within Guinea-Bissau is the Orango National Park, in the Bijagós Archipelago, with ca. 100 nests recorded per year.

Breeding season

In Guinea-Bissau, the olive ridley nests during the dry season, from December to May, with a peak of nesting during January and February.

Name in Krioul: Pikinino

Name in Bijagós: Emvara

Hawksbill, Eretmochelys imbricata

Distribution in Guinea-Bissau

In Guinea-Bissau, hawksbill turtles nest in Poilão Island, but their population there is very reduced, with under ten nests per year. Nesting also occurs in some islands of the Orango National Park, such as Adonga, and in Unhocomo and Unhocomozinho Islands, Ilhéu dos Porcos (South of Carache) and Nago Island (part of the Urok group of islands). Some nesting is also reported from Varela, in the mainland, but the extent of the hawksbill nesting population in the country is yet unknown.

Breeding season

As with the green turtle, the nesting season coincides with the rainy season, between July and December, but even in the dry season some nesting occurs.

Name in Krioul: Burmedjo

Name in Bijagós: Djassaka

leatherback, dermochelys coriacea

Distribution in Guinea-Bissau

In Guinea-Bissau, leatherbacks nest preferentially on the beaches of the Orango National Park, such as An-hôr beach, and on the islands of Unhocomo and Unhocomozinho, but they have also been registered on other Bijagos islands.

Breeding season

Nesting occurs during the dry season, from December to May.

Name in Krioul: Gigante

Name in Bijagó: Djummeme

Sea turtles have been around for over 120 million years. They have survived the mass extinction that decimated dinosaurs. Since prehistorian times humans have exploited sea turtles, mainly for the consumption of meat, eggs, and for religious ceremonies. Other products, such as oil, cartilage and shell, were also used in traditional medicine, or to manufacture jewellery and other luxury items. This has led to broad scale population declines and to local extinctions.

More recently, new threats became extremely important jeopardizing the sustainability of several populations globally: bycatch from industrial and artisanal fisheries, habitat degradation due to coastal development and mass tourism, coastal erosion, plastics and oil pollution, and the introduction of invasive species in breeding islands.

Seven species of marine turtles have survived to our days: the green turtle Chelonia mydas, the loggerhead Caretta caretta, the hawksbill Eretmochelys imbricata, the leatherback Dermochelys coriacea, the olive ridley Lepidochelys olivacea, the kemp ridley Lepidochelys kempii and the flat back Natator depressus.

Except for the flat back, found only in coastal waters of Australia and Papua New Guinea, and the kemp ridley, limited to the Gulf of Mexico and the subtropical and temperate Northwest Atlantic, the other five species have a global distribution, nesting on tropical (C. mydas, E. imbricata, D. coriacea, L. olivacea) or subtropical to temperate (C. caretta) sandy beaches.

Six of the seven species are listed in the International Union for the Conservation of Nature (IUCN) Red List: as ‘vulnerable’ (loggerhead, leatherback, olive ridley), ‘endangered’ (green turtle), and ‘critically endangered’ (hawksbill, kemp ridley).