Visitors to a popular British holiday island were alarmed to find a beach had become a 'graveyard' for crabs. The coastal spot was covered with thousands of the crustaceans, creating an astonishing spectacle.
However, rather then being live specimens, the crabs were in fact empty shells - left behind as part of a natural moulting process. The carcasses were the shells of spider crabs, which have distinctive spiny shells and long, spindly legs.
Each summer they they migrate from deep to shallower coastal waters to moult their shells. This is part of their life cycle that enables them to grow, North Wales Live reports.
The shells were left near Aberffraw, on the western coast of Anglesey. Many species of spider crab are found around the world, from the tiny kelp crabs of North America to the giant Japanese spider crab that can grow to 13ft.
Those off the Welsh coast are typically European spider crabs or, less commonly, smaller great spider crabs, with moulting and reproduction being closely linked with sea temperatures. July's exceptionally warm heatwave may have prompted a large number of crabs to shed their shells at the same time.
“I’ve never seen anything like it,” said Richard Lee, 59, a lorry driver from Lincolnshire who was making his first trip to the island. “It was a phenomenal sight. There were literally thousands of them.
“But there were no seagulls picking at the crabs, which you might expect if they had just died. It took me back a bit.”
Richard added: “The beach is a couple of hundred metres long and it was covered in them. If you walk through the crabs, you’ve got to watch out as their shells have sharp spikes - you don’t want to tread on them!”
