Thousands of spider crabs have swarmed the beaches at the height of the summer season in Cornwall.
A mass of them gathered in the shallow water at St Ives in Cornwall to shed their shells before returning to the depths of the sea.
While their presence at Porthgwidden Beach was enough to put many bathers off entering the sea, some did take the chance to snorkle above the carpet of crabs.
Spider crabs, that are instantly recognisable for their long legs and pincer claws, have a venomous bite that is poisonous to their prey but harmless to humans.
A mass of them gathered in the shallow water at St Ives in Cornwall to shed their shells before returning to the depths
While it is not unusual to see them in UK waters, mass gatherings like this one are becoming more common in the summer due to rising sea temperatures.
Once the crabs grow another tough outer shell they will disperse to depths of 300ft and paddling will become far more appealing.
Kate Lowe, a marine photographer, captured the event in the same week a woman snorkeller was bitten by a blue shark further around the Cornish coast, off Penzance.
Kate said: ‘I go snorkelling most of the time throughout the year but I have never seen spider crabs in such numbers.
While it is not unusual to see them in UK waters, mass gatherings like this one are becoming more common in the summer due to rising sea temperatures
‘When we turned up at the beach it looked as though there were lots of dark rocks under the surface.
‘But it turned out that there were thousands of crabs just two or three steps into the water.
‘It was just really incredible, they were only knee deep. I was able to float on the water above them and tried not to step on them.
‘A lot of the tourists were squeling at the sight of them.
‘Their shedded shells were just floating around.’