Green Turtle, Potato Grouper and Giant Tortoises
Aldabra Atoll Seychelles is Stronghold for Endangered Species
Feb 2, 2009
Conserving the habitat of a flagship species benefits the whole ecosystem.
The remoteness of Aldabra Atoll, together with the relative lack of human interference, has kept this habitat in pristine condition.
Aldabra Coral Atoll
- Aldabra Atoll is the second largest atoll in the world (after Christmas Island), and the lagoon is recognised as a World Heritage Site - managed by the Seychelles Island Foundation. It is 34 km long and 14.5 km wide, located In the Indian Ocean - off the East coast of Africa, North of Madagascar at 9°24′S 46°22′E.
- Aldabra was known to the Arabs (who named it) before being ‘discovered’ by the Portuguese in the early sixteenth century. After that it was owned by the French and then the British, before becoming part of the Seychelles Republic in the mid twentieth century. It nearly became a British/American military air base in the 1960s, but international protesting by ecologists averted the disaster.
- The Green Turtle (Chelonia mydas) is actually red, but the fat under the shell is a greenish colour – explaining the common name. It can be found in many tropical and subtropical seas where it feeds on sea-grasses.
- Habitat loss, both of suitable nesting sites and of sea-grass feeding areas causes severe problems for the Green Turtle. Aldabra Atoll is well supplied with sea-grasses, and the surrounding islands provide secure nesting sites.
- Aldabra is an excellent place to watch Green Turtles.
Potato Groupers
The Potato Grouper (Epinephelus tukula) is a very large predatory fish, over six feet long. It is one of the first species to suffer from overfishing of lagoons and reefs. Aldabra is one of the best places to see large Potato Groupers in the wild.
Giant Tortoises
- Aldabra has the largest population of Giant Tortoises in the world, with an estimated 100,000 living there. They have become the ‘flagship species’ for conservation work in the area. (They were origially known as Geochelone gigantea but have now been re-classified as Dipsochelys dussumieri,)
- In the past these large tortoises were often captured for food by passing sailors, and many islands that once might have had their own endemic species had populations exterminated.
- Aldabra Giant Tortoises have been re-introduced to many other islands in the Sechelles, and they are no longer threatened.
Threats to Endangered Species and Conservation Efforts
- Aldabra Atoll illustrates how a protected area can provide a safe habitat for a range of endangered species.
- Human influences are causing significant loss of critical habitats in many parts of the world. Protection of the lagoon, and with it of the rich sea-grass beds, has provided a haven for the Green Turtle. The coral islands surrounding the lagoon also provide essential nesting places.
- Removing fishing pressures allows species such as the Potato Grouper to grow to their full potential and establish themselves in their rightful place in the food chain. A healthy population of ‘top predators’ is good for the whole ecosystem.
- Having a well-publicised and easily recognised ‘flagship species’, such as the Giant Tortoise of Aldabra, helps focus public attention. Saving Giant Tortoises preserves habitats that are essential for many other, less well known, endangered species. Saving the tortoise saves the islands, which saves the lagoon and fringing reefs, which then allows the full ecosystem to flourish.
The copyright of the article Green Turtle, Potato Grouper and Giant Tortoises in Marine Conservation is owned by John Blatchford. Permission to republish Green Turtle, Potato Grouper and Giant Tortoises in print or online must be granted by the author in writing.
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