Â鶹Éç

(MCS) needs help in recording the movements of one of the lesser spotted visitors to UK shores and is urging everyone from coastal path walkers to sea users, to look out for leatherback turtles.

Leatherback turtle by Mike Daines

Weighing up to a tonne and measuring almost three metres in length, these incredible creatures are unlike any other reptile in that they can maintain their own body heat up to18 degrees centigrade warmer than even the chilliest of British summer seas.

While leatherback turtle populations face extinction in the Pacific and Indian Oceans, many nesting populations in the Atlantic appear to be increasing.

MCS Biodiversity Programme Manager, Dr Peter Richardson, said it's not clear why the Atlantic Ocean has become the last stronghold for the leatherback turtle: "While conservation action at important nesting beaches is likely to be playing a part, it may also be due to the increasing availability of their jellyfish prey, combined with collapses in the populations of predatory fish such as tuna and sharks."

August is the peak time to see leatherback turtles in UK waters, as they arrive from their nesting grounds in the Caribbean to refuel on our abundant seasonal jellyfish blooms.

So far this year 12 sightings have been reported from south west Wales and England, seven of which have been seen in the last fortnight. "The leatherback is the largest of all marine turtle species and at a distance could be mistaken for a floating log, but if you approach them slowly and carefully, once you see their large reptilian head, massive flippers and ridged leathery shell you can't mistake them for anything else," said Dr Richardson.

MCS has been encouraging the reporting of marine turtles in UK waters since 2001, and leatherbacks make up 75 per cent of those sightings already recorded. To help identify turtles in UK waters, spotters can download , created by MCS with support from and . The code describes the different species and how to identify them and who to report them to.

UK and Ireland turtle encounters can also be reported to MCS online at .