By Alex Kirby BBC News Online environment correspondent

UK scientists, conservationists and the fishing industry are joining forces to help endangered marine turtles off British coasts.

They are working together to learn more about the species which visit the UK. They are also co-operating to reduce the number of turtles meeting accidental deaths.

Plans are afoot to fit an electronic beacon on a turtle to monitor its movements by satellite.

The initiative was announced by the Marine Conservation Society (MCS), which is holding a workshop on 2 March to plan a turtle research programme.

There it will launch a code, devised by a coalition of organisations which make up the Turtle Implementation Group.

Keen to help

The code encourages fishing crews, sailors and other sea users to report immediately all encounters with turtles in British waters. Copies are available free from MCS.

Litter is the biggest threat in the UK (Image: MCS)

The code also provides advice on how to rescue turtles entangled in fishing gear. MCS says four or five incidents are reported annually, but it thinks this underestimates the true figure.

It says the response from the fishing industry has been "overwhelmingly positive", with many crews eager to be involved in surveying turtle numbers.

Five of the seven species of marine turtle are found off the UK - the leatherback, loggerhead, Kemp's ridley, hawksbill and green turtle.

But the only regular visitor is the leatherback, the largest species at almost 3 metres (10 feet) long and weighing up to 916 kilograms (2,020 pounds). The other turtles arrive here by accident.

There are thought to be only 26,000 nesting female leatherbacks worldwide. They nest throughout the tropics, and are hunted for their meat and eggs on land, and caught in nets in the open sea.

Mistaken prey

Apart from the risk of entanglement in fishing gear, they are also at risk from marine litter.

Sue Ranger of MCS told BBC News Online: "Litter is a more serious problem than getting tangled up.

MCS plans to tag a leatherback (Image: Mike Daines)

"Post mortems on leatherbacks which die in British waters invariably find they've swallowed plastic litter.

"They have downward-facing spines in their throats to help them to swallow the slippery jellyfish on which they feed.

"So even if they realise they've taken in a plastic bag or balloon or some other debris, it's very hard for them to get rid of it before it blocks their guts.

Resisting the cold

"They're international travellers - most that come here are from west Africa or the Caribbean.

"We have a satellite beacon on standby, waiting for a suitable turtle to attach it to, so we can find out where they go when they leave."

Leatherbacks, unlike the hard-shelled turtles, have rubbery carapaces, not unlike a diver's wetsuit, with a thick skin covering hundreds of irregular bony plates.

Uniquely among reptiles, they can maintain their temperature above that of their surroundings, which enables them to cope in the cold British seas.