MORE than 80 Columbus crabs, which are rarely seen in the UK, have washed up with the mystery box on a Dorset beach.

Marine conservationist and photographer Steve Trewhella said he found 83 of the creatures when he went to investigate the box.

The crabs, which come from Bermuda, live on floating objects and have been carried by Atlantic currents and storms to the UK.

In this instance on a mystery box which washed up on Boscombe beach on Monday morning.

The coastguard was called to investigate the box which is believed to be part of a pontoon that had broken away, and contained nothing but foam.

And while the box itself carried nothing of interest it appears to have travelled almost 4,000 miles before washing up on the Dorset coast.

According to Steve the pontoon and large piece of rope that was attached was carrying 83 live Columbus crabs.

"These crabs live in the Sargasso sea in the Caribbean so this box must have at least travelled through there before finding its way to Boscombe," said Steve, 51.

"It's amazing really to think that such a large number of them have travelled all that way and are still alive.

"It is also the largest number of these crabs which have ever been found on one object in the UK - the most ever recorded until now was 17.

The Marine Conservation Society (MCS) said the first UK sighting of the crabs was reported in 2007 and it could be happening more due to changing weather patterns.

But Steve also believes the increase in numbers is also down to an "astonishing amount of debris and litter going into the sea, creating artificial habitats for these species to come over."

"The introduction of plastic has created an artificial corridor transporting these creatures across the Atlantic.

"On the one hand it's exciting for me to get to see them, and such large numbers of them, but at the same time it's worrying how they got here in the first place.

"An estimated 6.4 million tons of rubbish enter the worlds seas and oceans a year , as you can see many of these are very large and potentially dangerous to both shipping and wildlife."

Columbus crabs are about the size of a 50p piece - but according to Steve these ones are the largest he's ever seen.

"The next task is to examine and log information on the crabs and the black box, which we now know is a floating dock made in Follansbee, West Virginia, USA."

Steve will be taking a bucket of the crabs to the Oceanarium in Bournemouth and to other wildlife centres in the area.

To find out more about many of the other interesting creatures and objects Steve has found on Dorset's coast go to www.ukcoastalwildlife.co.uk.