JANUARY 2011: My Surface Interval named one of the best scuba diving blogs

Wednesday, January 5, 2011

Sea Turtles migrate thousands of miles across the Atlantic

THEY are one of the top sights underway and new scientists have discovered a way of maximising chances of seeing them - diving close to the major currents that rip across the Atlantic.

Researches tagged 25 loggerhead turtles to discover their movements and data from tags on their backs show they swim thousands of kilometres each year.

These journeys take them through areas where they are at high risk of being caught accidentally by fishing boats.

The leatherback is the world's biggest turtle and listed as Critically Endangered, largely because of poaching for eggs and snaring in fishing gear.

Writing in the Royal Society journal Proceedings B, an international group of researchers found nesting sites increased in number the closer to the Gulf Stream System (GSS) that traverses the Atlantic, the ocean current to which hatchlings in this region migrate.

The South Atlantic leatherbacks adopted three different patterns. Some swam west and remained in the tropical Atlantic waters. A second group swam south-west until they reached the coast of South America, and foraged in shallow waters there; while the remainder moved southwards down the western coast of Africa.

It is thought that young turtles require the currents to sweep them from their nesting sites, hence why mothers choose to lay their eggs on beaches closer to the current system.

Scientists hope the study will go some way towards protecting the turtles who are at risk from being trapped by long line fishing practices or gillnets.

Matthew Witt from Exeter University, the study's lead author, told the BBC: "The reason for doing the project is to understand the turtles' movements, but the context is that the Pacific population recently went through a huge decline.

"Part of the reason for that is interaction with fisheries - so it seemed very pertinent to get a better understanding of what the South Atlantic leatherbacks are up to."

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