Army of crabs in Cornwall delights photographers and swimmers

Swimmers and beachgoers have been sharing stunning images of hundreds of spider crabs around Cornwall.

The aggregation - or gathering - happens annually but has delighted snorkelers and swimmers in the county.

Katie Maggs, who filmed it, said: "With many people thinking all the crabs were washing up dead it is, in fact, just their old shells being moulted.

"The crabs are very clever as they come together in huge groups at this vulnerable time for mass protection to lose their old shell exposing a softer new one."

Ms Maggs, who is also part of the British Divers Marine Life Rescue team, said the sighting was in south west Cornwall.

"Honestly the most amazing thing I have seen in a very long time," she added.

The snorkelling instructor shared the video on her Instagram page Tonic of the Sea.

Kate Lowe also shared her images on her Instagram.

She said: "I arrived at low tide to see hundreds of spider crabs in the shallows.

"It's the first time I've snorkelled with such a huge number of crabs and it was an incredible sight."

The empty crab shells were later seen on several beaches.

Spider crabs are a common species in Cornish waters and have long spiny legs and claws.