The apparent sight of dead crabs strewn across the beaches of Anglesey in North Wales has raised concerns about what could have caused so many shellfish to die simultaneously.

Photographs show the legs, claws and shells of beached spider crabs in various states of dismemberment and decomposition.

However, bathers have been reassured that the apparent mass mortality is not what it seems.

Each year, the species not only migrates to warmer waters and then returns again to its breeding grounds, but also molts, losing its spiny exoskeletons, including its legs, claws and even eye stalks, and emerges again. bigger than before.

The gruesome scene on the shore, in which many crabs appear completely whole, is simply the result of the crabs’ natural molting process – similar to how snakes shed their skin.

When crabs molt, they emerge from behind their shells and are temporarily soft-bodied and therefore vulnerable to predators.

Despite this explanation, there are fears that the worsening climate crisis could warm UK waters enough to see a huge proliferation of spider crabs around the coast.

Tim Harris, who visited Traeth Mawr beach in Anglesey last week, reported the phenomenon to Natural Resources Wales and said: ‘It is no exaggeration to say there are thousands and thousands of stranded.”

Richard Lee, who photographed the piles of crabs, described it as a “really strange phenomenon”, adding that there were “thousands and thousands of them”.

At this point in their life cycle, they become very gregarious – for sure numbers – and they congregate near the seashore in an extra effort to avoid predators.

Despite the reported boom in spider crab numbers in UK waters, there is little market in Britain for spider crab meat, despite it being considered a delicacy in European countries, including Spain and France.

Additionally, crabs landed in Britain are now more difficult to export to European markets due to Brexit.

Before Brexit, around 85% of spider crabs caught off the Cornish coast were exported to Spain, but new red tape due to the vote to leave the EU means additional red tape and border checks.

Last year, fishing in the UK debated the ‘renaming’ of spider crabs to ‘Cornish king crabs’ to appeal to British diners.

Along with soaring spider crab numbers and a simultaneous collapse in demand, anglers are further aggravated by the presence of the crabs, Hastings anglers say The Independent the creatures’ sharp spiny shells cause significant damage to their nets.