Rare crabs cross Atlantic on buoy
Six Columbus crabs have found a new home in the UK after travelling across the Atlantic Ocean on the back of a buoy.
The crabs, which measure about half an inch in diameter, are thought to have come from the Sargasso Sea off the coast of Bermuda.
Professional marine wildlife photographer and author Steve Trewhella spotted the rare find, which was first reported in the Western Daily Press.
Speaking to The Royal Gazette, Mr Trewhella said he found the exotic crabs on a barnacle-encrusted buoy on Chesil Beach in Dorset, England, on Monday.
“Columbus crabs are particularly rare,” he said. “They only live in tropical oceanic waters in the Pacific and Atlantic Oceans. It is not a species we would ever expect to see in the UK.”
Because the buoy was covered in goose barnacles, which are known to come from warmer climates, Mr Trewhella suspected the object and the crabs originated from the Sargasso Sea and were brought to the UK by the Gulf Stream.
“The Sargasso Sea is their habitat,” he said. “They only live on floating objects predominantly with goose barnacles because they feed on the larvae.
“We'll never know for absolute certain where they came from — we're going on the associated species we found with them. Everything is pointing to that part of the world.”
Mr Trewhella said that while there had only been about 50 recorded sightings of the species in Britain, they could be arriving more frequently because of the dramatic increase in marine litter and debris, which provide ideal habitats for the small crabs.
“We are undoubtedly finding more and more debris from across the Atlantic,” he said, adding that he found another Columbus crab inside a 6ft pipe on Tuesday.
He said he was excited about the discoveries, but was concerned about the wider implications of this species arriving in Britain in greater numbers.
“They're only crabs at the end of the day but is their arrival on a regular basis telling us something is happening with the Gulf Stream? These animals have the potential to settle in the UK.”
Mr Trewhella and his wife, Julie Hatcher, a marine biologist, have been studying long-haul drifts arriving in the UK from the United States and Canada for the past few years.
They were beachcombing when Mr Trewhella came across the 40lb buoy. But it was not until he took it home and began investigating it more closely that he discovered the crabs.
“They're very cute little things, they're lovely and quite exciting if you think about how far away you are,” he said, adding that they are now thriving on a flip-flop in his aquarium.
Together with his wife, Mr Trewhella has written a book, The Essential Guide to Beachcombing and the Strandline, about the exciting finds to be made on British beaches. He now hopes to expand on his research and is interested in starting a project in collaboration with local specialists in Bermuda.
“I'd like to think there is someone in your part of the world who would be interested in these animals that are washing up thousand and thousands of miles away,” he said.
Mr Trewhella would like determine the exact origin of the crabs and how long it took them to travel across the Atlantic Ocean, as well as get assistance on identifying other unfamiliar species that are being washed up on British shores.