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.
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 classified in the International Union for the Conservation of Nature (IUCN) Red List, either as ‘vulnerable’ (loggerhead, leatherback and olive ridley), ‘endangered’ (green turtle) or ‘critically endangered’ (hawksbill and kemp ridley).
FOUR of the seven extant species of sea turtles NESTS in Guinea-Bissau