How satellite tracking revealed the migratory mysteries of endangered Atlantic loggerhead turtles

May 22, 2006

Their journeys are among the longest in the animal kingdom and until now they have largely remained a mystery. But now an international team of scientists led by the University of Exeter have uncovered the migratory secrets of endangered loggerhead turtles in West Africa and the results could have huge implications for strategies to protect them.

In a paper in the journal Current Biology, Dr Brendan Godley and an international team describe how they used satellite tracking systems to follow the journeys of ten turtles from Cape Verde, West Africa, which is one of the world's largest nesting sites for loggerheads and a hotspot for industrial fishing. What they found could turn current conservation strategies upside down, as the team discovered the turtles adopted two distinct approaches to finding food, linked to their size.

Previously it was thought that hatchlings left the coastal region to forage far out at sea before returning, later in life, to find food closer to shore. However the new findings show that the oceanic habitats contained far larger animals than was previously thought. The team tracked the turtles as they left nesting sites, following them for up to two years over ranges that covered more than half a million square kilometres.

Dr Brendan Godley, of the University of Exeter, said: "We were surprised to find such large turtles looking for food out in the open ocean, as it was previously thought that animals of this size would have moved back to forage in coastal zones. This means there are much greater numbers of the breeding population out at sea and far more that are vulnerable to the intensive longline fishing effort that occurs in that region."

He added: "From the information collected, we have been able to determine how much time these animals are spending within the sovereign boundaries of each country in the region. This research highlights how complicated the migration of marine vertebrates really is and how sophisticated our conservation efforts must be to safeguard these animals. Given the range these reptiles can cover an international cooperative effort in seven African states is needed to create a strategy that would protect them."

Research* shows that in 2000 1.4 billion hooks were cast into the world's oceans through industrial fishing. It's thought that globally more than 200,000 loggerhead turtles were incidentally caught by fisherman scouring the waters for other species such as tuna and swordfish. Of these, tens of thousands are thought to die as a result. 37% of this fishing effort was in the Atlantic and a major hotspot for fishing is found off West Africa, the region where the Cape Verdean turtles reside.

In recent years marine turtle researchers have been using satellite telemetry to track turtle migrations. Satellite transmitter tags are attached to the shell of the turtle so that every time the turtle surfaces to breathe, the tag transmits the turtle's position, as well as other information (e.g. depth and duration of dives), to satellites orbiting above, which then relay the data by e-mail to the computer of the scientist who attached the tag. For more information about tracking sea turtles, visit

Source: University of Exeter

Explore further: Glowing sea turtle, like red and green spaceship, spotted

Related Stories

Glowing sea turtle, like red and green spaceship, spotted

September 30, 2015

Seen off the Solomon Islands: The hawksbill sea turtle—glowing. Sharks, fish, corals, can shine and now we know that the sea turtle can too. Jane J. Lee reported on Tuesday in National Geographic (and environmental news ...

Sea turtles face plastic pollution peril

October 9, 2015

A new global review led by the University of Exeter that set out to investigate the hazards of marine plastic pollution has warned that all seven species of marine turtles can ingest or become entangled in the discarded debris ...

New study tackles conflicting goals in the Coral Triangle

September 15, 2015

An international team of scientists is using one of the world's natural wonders, the Coral Triangle of Southeast Asia, to pioneer a new approach that conserves wildlife, protects people's livelihoods and helps both adapt ...

How mercury contamination affects reptiles in the Amazon basin

September 21, 2015

Mercury contamination in water and on land is of worldwide concern due to its toxic effects on ecosystems and human health. Mercury toxicity is of particular concern to reptiles because they are currently experiencing population ...

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.