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Marine Turtles
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There are seven marine turtle species and the flat-backed turtle is the only one that isn't either endangered or critically endangered. Turtles are ancient reptiles that survived the extinction of the dinosaurs, but without urgent action their days may be numbered.
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| Leatherback turtle |
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|  | The leatherback turtle has a unique biology among turtles. Its circulatory system and internal shell structure enable it to withstand cooler temperatures and dive deeper than other species. It often turns up in UK waters.
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| | Leatherback turtles are critically endangered. Recent estimates suggest the global population may be as low as 34,000 nesting females. Leatherbacks have disappeared completely from parts of their former range and numbers are falling so rapidly they could be extinct by 2030. Marine reserves and captive breeding programmes have been established to try to halt their decline.
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| | Bycatch is the main threat. A global ban on longline and gillnet fishing could be the only way to save them. The problem is most acute in the Pacific where it's estimated that as few as 2,300 adult females remain. Leatherbacks are the world's largest turtles, reaching 2.4m in length. For the larger ones, TEDs (Turtle Excluder Devices) are ineffective because they are too big to get through the escape hatches.
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| | In places like Guyana, Trinidad and Mexico, leatherback eggs are taken for food and to be smuggled abroad. The meat is more likely to be used as a source of oil than as food.
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| | Leatherback turtles eat jellyfish and they often mistake plastic bags for their main food source. If plastic is ingested by turtles, it usually results in a slow and painful death. Leatherbacks have, in effect, a one-way digestive system which makes them unable to regurgitate food. The plastic gets stuck and the turtle starves.
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| | For further species information see ARKive.
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| Hawksbill turtle |
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| | The hawksbill turtle is one of the smallest marine turtles. It is found in tropical waters, from the eastern Atlantic to south Asia, Australia and Indonesia and on various coasts around the American continent.
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| | The hawksbill is critically endangered and at risk from all the threats listed above. The main cause of its decline, however, is the illegal trade in shell. The tortoiseshell that is used in jewellery and ornaments comes from the hawksbill. Despite the CITES ban, there is still strong demand for tortoiseshell in Japan and other countries in east and south Asia.
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| | For further species information see ARKive.
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| Olive ridley turtle |
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| | Although one of the more numerous of the turtle species, the olive ridley is still endangered. It nests on just five beaches in Mexico, Costa Rica and north-east India and vast numbers turn up at the same time to lay their eggs. The turtles may have evolved this pattern to overwhelm natural predators, but the strategy doesn't allow for human activity.
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| | On the beaches of the Orissa province in India, it is estimated that as many as 120,000 turtles have been killed in the last decade. When the turtles congregate a little way from the shore, they are caught in mechanical fishing devices and drown. Despite a 5km protection zone, trawlermen still flout the wildlife protection laws and are reluctant to fit the mandatory TEDs.
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| | In South and Central America, the mass arrival is a natural bonanza for local communities and the illegal trade. Here, turtles are deliberately targeted. There is a huge demand for eggs which are believed to have aphrodisiac qualities. In the largest seizure recorded, a lorry in Mexico City was found to contain some 500,000 eggs, all taken from one beach.
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| | The adult olive ridley is also still hunted illegally for its meat and skin, although not to the extent it was in previous decades. It also has a very unfussy eating habit which is a big problem when it tries to eat plastic bags and other rubbish that ends up in the sea.
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| | For further species information see ARKive.
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| Kemp's ridley turtle |
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| | The Kemp's ridley is similar to the olive ridley and is critically endangered. It is the most endangered of all the sea turtles.
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| | It only nests on a limited stretch of coastline in the Gulf of Mexico. Here, conservation efforts and the introduction of TEDs have seen the number of nesting females rise from an all-time low of a few hundred in the 1980s to around 1,000 now. The nesting population is, however, still nowhere near the 100,000 seen on a single day less than 70 years ago. Shrimp trawling and pollution continue to cause problems.
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| Green turtle |
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| | The green turtle is found in tropical seas and is classified as endangered. The species was widely targeted by commercial turtle fisheries and many former nesting sites have now been developed. They are now threatened by fishing activity and illegal hunting.
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| | Their meat is an important source of protein for communities in the Caribbean, Mexico and South America where it is used in turtle soup.
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| | Another major concern is the high incidence of debilitating tumours found in green turtles. This may be linked to marine pollution. Conservation efforts have included the relocation of eggs laid on public beaches.
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| | For further species information see ARKive.
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| Loggerhead turtle |
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| | Loggerhead turtles are classified as endangered. They are highly migratory and spend most of their lives out in the open ocean where they are often caught in fishing nets and lines.
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| | Although hunting is less of an issue than for other turtle species, both meat and eggs are highly prized by traditional communities in the Caribbean and Antilles and loggerhead turtle shells are used to make paddle boats in Honduras.
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| | Loggerhead turtles are also found in the Mediterranean. They nest on beaches in Greece, Turkey, Israel, Tunisia and Libya. Here they are at risk from coastal development and tourism that disrupts nesting sites.
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