Green turtle; Tortue comestible, tortue franche, tortue verte (Fr); Tortuga blanca, tortuga verde (Sp)
IUCN: Endangered A2bd CITES: Appendix I CMS listing: Appendix I and II
Approx. 203,000 nesting females
Widely harvested for meat
Equally as worrying are the high numbers, in some areas, of green turtles suffering from debilitating and potentially lethal tumours. The cause of these tumours is unknown but there is suspicion that increasing chemical pollution levels might make turtles more vulnerable.
From 80 to 150cm in length and up to 130kg in weight.
Dark black-brown or greenish yellow.
Current Population and Distribution
There are important green turtle nesting and feeding grounds around the whole coast of Africa, India and South East Asia, along the entire tropical coastline of Australia and the South Pacific Islands. They are also found in the Mediterranean and occasionally as far north as the coastal waters of Great Britain.
In the West Atlantic the range extends from Cape Cod through Central America as far south as southern Brazil. Populations in the Eastern Pacific stretch from northern USA to the southernmost record in northern Chile. Nesting occurs widely throughout the range, even on the central Pacific islands, where few other species of nesting turtles now occur.
A current estimate of worldwide numbers of breeding female green turtles is 203,000. 1989 data suggest the main nesting beaches were in Queensland, Australia and in Indonesia.
Current estimates suggest the age of sexual maturity is 45 to 50 years. Females migrate huge distances between feeding grounds and nesting areas, but tend to follow coastlines rather than cross open water.
An individual female nests approximately every 3 years, and lays 1-6 clutches of between 70 and 110 eggs. The incubation period lasts 50 to 70 days.
Adult green turtles are the only truly herbivorous marine turtles. They feed mainly on seagrasses or algae, mostly in the tropics and subtropics.
Indo-Malayan, Indo-Pacific, Palearctic, Nearctic
Mediterranean Sea, Northeast Atlantic Shelf Marine, Southern Australian Marine, Benguela Current, Humboldt Current, Agulhas Current, Western Australia Marine, Gulf of California, Galapagos Marine, Canary Current, Sulu-Sulawesi Seas, Bismarck-Solomon Seas, Banda-Flores Sea, Great Barrier Reef, Palau Marine, Andaman Sea, Arabian Sea, East African Marine, West Madagascar Marine, Mesoamerican Caribbean Reef, Greater Antillean Marine, Southern Caribbean Sea, Northeast Brazil Shelf Marine
What are the main threats?
- Habitat loss and degradation
- Wildlife trade
- Collection of eggs and meat for consumption
- Incidental capture (bycatch)
- Climate change
Green turtle consumption in Bali peaked in the late 1970s when more than 30,000 green turtles were landed each year. In 2002, landings were estimated at 684 green turtles per month.
A further factor affecting green turtles is disease. On some of the Hawaiian Islands, almost 70% of stranded green turtles are affected by fibropapillomas, a tumorous disease that can kill marine turtles. While the cause of the tumours has not yet been discovered, a herpes-like virus that causes similar tumours has been identified in the wild.
It has been suggested that the increased occurrence of fibropapillomas may be the result of run-off from land or marine pollution that may weaken the turtles immune system, rendering them more susceptible to infection by the wild herpes-like virus.
Why is this species important?
Seagrasses and algae on which green turtles feed also happen to be amongst the most productive ecosystems on the planet as well as providing a nursery for many species of invertebrates and fish.
What is WWF doing?
- Action to address the impacts of climate change.
- Monitoring the migration patterns of marine turtles.
- Improving and supporting trade controls.
- Protecting nesting sites.
- Reducing bycatch and promoting smart fishing.