South West Wales

Green sea turtle migrates huge distance in Indian Ocean

Green sea turtle with tracker device Image copyright College of Science, Swansea University
Image caption Eight green sea turtles were fitted with tracker devices

A green sea turtle migrated a staggering 3,979 km (2,472 miles) in a year, according to Swansea University researchers.

An aerial was attached to the back of eight turtles by scientists using satellite technology to monitor the species' habits.

The project found one travelled from the Chagos Islands in the Indian Ocean to the coast of Somalia in east Africa.

It is believed to be the furthest green sea turtle migration recorded.

The Swansea scientists, collaborating with colleagues in Australia and the Seychelles, were investigating the effectiveness of marine protected areas which have been set up by governments around the world over the last decade to improve conservation and protect species and biodiversity from damage and disturbance.

Published in the latest issue of Conservation Biology, the research team found

  • Seven of the eight tracked turtles migrated to foraging grounds which lay outside a protected boundary around the Chagos Islands
  • Only one of the eight tracked turtles remained inside the protected area after the breeding season had finished

The study focused on the green sea turtles which breed on the Chagos Islands in the Chagos Archipelago which became a protected area in 2010, according to Prof Graeme Hays from the College of Science at Swansea University.

Image copyright BS and RD Kirkby
Image caption Juvenile sea turtles feed on small fish, crustaceans and jellyfish but adults eat seagrass

"The message from this research is that networks of small protected areas need to be developed alongside larger ones so species which migrate over long distances can stay in safe zones for as much time as possible," he said.

Image copyright Swansea University
Image caption Prof Graeme Hays with one of the sea turtles


  • The average life span of a green sea turtle in the wild is over 80 years
  • They grow up to 5ft (1.5 m) and weigh up to 700 lbs (317 kg)
  • Adults feed on seagrass
  • Like other sea turtles, the green turtle cannot pull its head into its shell
  • Green sea turtles (Chelonia Mydas) are reptiles whose ancestors evolved on land and took to the sea to live about 150 million years ago

Source: National Geographic

Nicole Esteban, a Swansea University researcher who has worked on the project, said: "Green sea turtles are an iconic species and their welfare tells us a lot about the health of our oceans.

"They forage in seagrass meadows which are being depleted because of pollution and other man-made causes.

"Our study helps determine the location of these important habitats, and also highlights the need to protect seagrass meadows, and make a network of small marine protected areas (MPAs)."

Last year, the Welsh government withdrew plans for 10 marine conservation zones in favour of exploring changes to 125 Marine Protected Areas (MPAs) that cover 36% of Welsh seas.

Image copyright kirkby
Image caption The average life span of a green sea turtle is said to be over 80 years

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