Green turtle

An estimated 100,000 killed in the Indo-Australian archipelago each year

Common Name		Green turtle; Tortue comestible, tortue franche, tortue verte (Fr); Tortuga blanca, tortuga verde (Sp)
Scientific Name		Chelonia mydas
Status		IUCN: EN A2bd (Endangered); CITES: Appendix I CMS listing: Appendix I and II
Population		Approx. 203,000 nesting females

Background

This information has been reviewed.

This species is widely distributed in tropical and subtropical waters, but is under threat everywhere from over-harvesting of both eggs and adults, and from accidental mortality in the nets and long-lines of fishing fleets. The Mediterranean population is categorized as Critically Endangered in the IUCN Red List.

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.

Green turtles are widely harvested for meat in many tropical countries. WWF is working with governments to develop and enforce regional conservation agreements such as the Inter-American Convention on the Conservation of Marine Turtles.

WWF is also working with local communities in the Indian and Pacific Oceans to ensure that traditional or subsistence take levels are sustainable, and where necessary to find alternative sources of income.

Physical Description

So called because of the greenish colour of their cartilage and the fat deposits around their internal organs, green turtles are black-brown or greenish yellow in colour. They grow up to 1.5 metres long and can reach 200 kg, but individuals from different populations vary widely in size. The carapace is oval when viewed from above, and the head is relatively small and blunt.

Controversy rages about splitting Chelonia mydas into subspecies based on the many size differences between populations in different parts of the world. The population found in the eastern Pacific is often called the black turtle, and is sometimes described as a separate species (Chelonia agassizi).

Individuals from the East Pacific are smaller than their counterparts in the Western Caribbean in a wide range of external measurements, and are particularly dark in colour, a trait that has shown to be genetically influenced.

Size
Green turtles range from 80 to 150 cm in length and can reach 132 kg in size

Colour
Dark black-brown or greenish yellow.

Habitat

Biogeographic realm
Indo-Malayan, Indo-Pacific, Palearctic, Nearctic

Range States
American Samoa, Angola, Anguilla, Antigua and Barbuda, Australia, Bahamas?, Bangladesh, Belize, Benin?, Brazil, British Indian Ocean Territory, Cambodia?, Cameroon?, Cape Verde?, Chile?, China, Colombia, Comoros, Congo?, The Democratic Republic of the Congo?, Cook Islands, Costa Rica, Cuba, Cyprus, Côte d'Ivoire?, Djibouti?, Dominica, Dominican Republic, Ecuador (Galápagos), Egypt, El Salvador?, Equatorial Guinea, Eritrea, Fiji, French Guiana, French Polynesia, Gabon?, Ghana?, Grenada, Guadeloupe?, Guam, Guatemala?, Guinea?, Guinea-Bissau?, Guyana, Haiti, Honduras?, India, Indonesia, Iran, Jamaica, Japan, Kenya, Kiribati, Kuwait, Liberia?, Madagascar, Malaysia, Maldives, Marshall Islands, Martinique, Mauritania Mayotte, Mexico, Federated States of Micronesia, Montserrat?, Mozambique, Myanmar, Netherlands Antilles , New Caledonia, Nicaragua, Nigeria?, Niue, Northern Mariana Islands, Oman, Pakistan, Palau, Panama, Papua New Guinea, Peru, Philippines, Puerto Rico, Qatar?, Réunion (Mozambique Channel Is.), Saint Helena (Ascension), Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Samoa?, Sao Tomé and Principe, Saudi Arabia, Senegal, Seychelles, Sierra Leone, Solomon Islands, Somalia, Sri Lanka, Sudan?, Suriname, Taiwan, United Republic of Tanzania, Thailand, Togo?, Tokelau, Tonga, Trinidad and Tobago, Turkey, Turks and Caicos Islands, Tuvalu, United Arab Emirates, United States, United States Minor Outlying Islands (US Line Is.), Vanuatu Venezuela, Viet Nam, British Virgin Islands, Virgin Islands (U.S.), Western Sahara?, Yemen

Ecological Region
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

Why is this species important?

Marine turtles fulfil important roles in marine ecosystems
Seagrasses and algae are the green turtles' preferred snacks, and also happen to be amongst the most productive ecosystems on the planet. Green turtles both help to maintain the seagrass beds and make them more productive. Without grazing by green turtles, the seagrass blades grow tall and get choked by sediments that obscure the light and promote disease.

Additionally, seagrass consumed by green turtles is quickly digested and becomes available as recycled nutrients to the many species of plants and animals that live in the seagrass ecosystem. Seagrass beds also function as nurseries for several species of invertebrates and fish, many of which are of considerable value to commercial fisheries and therefore important to human food security.