Technology hope for turtles

On the beach in French Guiana: A leatherback digs her nest (© WWF Canon/Roger Leguen)

By BBC News Online's environment correspondent Alex Kirby

Conservationists say the number of leatherback turtles dying in one of their main strongholds has reached alarming levels.

The leatherbacks, the largest turtles in the world, are coming into increasing conflict with fishing boats.

WWF, the global environment campaign group, says the number of turtles dying this way has increased seriously in recent years.

But technology offers the prospect of monitoring the turtles better, and saving most from death.

The area WWF is concerned about stretches from Brazil to Venezuela, and includes French Guiana, Surinam, and Guyana.

Nobody knows how many leatherbacks there are, but scientists believe about half of them nest on the beaches of the Guianas coast.

Drowned in nets

The species is classified by the US government as globally endangered, and is on appendix one (the most threatened category) of the UN Convention on International Trade in Endangered Species (Cites).

WWF says hundreds of leatherbacks have died during the current season, probably because of increased fishing near their nesting beaches. The turtles drown after becoming entangled in the nets, or are injured as they are cut free.

A risky world awaits this leatherback hatchling (© WWF Canon/Roger Leguen)

WWF says 11 dead leatherbacks were being found on the beaches of French Guiana every day in April. In June it found 12 turtles in a single net at sea, only one of them still alive.

It is urging the governments of the region to enact and enforce legislation to protect the turtles (some already have laws in place, but WWF says they are largely inadequate).

Callum Rankine of WWF told BBC News Online: "We are seriously concerned, because the death rate is way too high - it's massive.

"Leatherbacks take a long time to mature, they live for many years, and they produce few young.

"If more than a few are lost, it'll be unsustainable. And we won't know until it's too late.

"Computer models show this population in the Atlantic will crash, just like the leatherbacks did in the Pacific in the last 20 years or so.

Escape hatches

"If we don't do anything, it could happen within the next couple of decades.

"But there are ways governments can reconcile the fishing fleets and the turtles. One is to make sure the boats use TEDs - turtle excluder devices, which are already mandatory in Surinam and Guyana.

"They're spring-loaded traps in the nets - the turtles can escape through them, but the shrimps can't. They can save up to 90% of the turtles.

Found off the UK: A large leatherback

"The other way technology can help is through tracking populations and individual animals' movements.

"Basically, you glue a backpack on the turtle's shell, with an aerial sticking out of it, transmitting data to a satellite.

"It's seriously silly-looking. But it feeds back information on where the turtle is, where it's been, how deep it's dived, and so on. And leatherbacks have a real wanderlust."

Leatherbacks are the largest sea turtles, travelling furthest, diving deepest and venturing into the coldest water.

Range of threats

They can reach eight feet (2.4 metres) in length, and instead of a visible shell they have a carapace made up of hundreds of irregular bony plates, covered with a leathery skin.

Their eggs are often taken, though they are seldom hunted for their meat. Other threats include disease and pollution.

Leatherbacks sometimes mistake plastic bags and balloons for the jellyfish on which they feed, often with fatal results.