Thousands of crabs pictured just beneath surface off beach in St Ives
A local photographer caught the natural phenomenon on camera!
Last updated 9th Aug 2022
A woman from Cornwall has posted a photo showing thousands of spider crabs close to the shoreline on a beach in St Ives.
The image, which captures the animals underneath the shallow water, is a rare occurrence where the creatures gather to protect themselves as they moult their shells.
Local photographer Kate Lowe, who posts on Instagram as cornish.coast, said: "What we initially thought at low tide was lots of just dark rocks and seaweed on the surface. When we got closer to the shoreline we realised it was lots of spider crabs. It was an amazing surprise.
"We found a channel where they weren't around so we could walk in and then we started to float around waist deep water.
"It was amazing we had the time to just really stay there and take in the experience. It was just brilliant, a thoroughly enjoyable experience".
The undersea spectacle, which takes place annually between late summer and early autumn, involves crabs rallying together to protect themselves from the threat of predators.
It is because they are extremely vulnerable during the moulting process, as they crack open their exoskeletons and grow a new outer shell.
Kate continued: "I've often snorkeled in our local area and I've seen individuals and around this time small groups but I've never seen them in such large numbers before".
However, the scene at St Ives is not the first time it has happened in Cornwall!
A mass aggregation of male crabs was filmed last year, in knee-deep water just a few metres from a popular Falmouth beach at low tide.
Matt Slater, Cornwall Wildlife Trust's Marine Conservation Officer who filmed the incredible gathering, said: "I have seen spider crabs on every dive and snorkel I have done for the past four years, but I have never seen a group as large as this! Looking down at the mass of crabs scuttling on the seabed was a truly incredible experience.
"Our seas are full of surprises - most locals would have no idea that one of the world’s great wildlife aggregations is occurring not too far from where they sleep. It goes to show how important our Cornish seas are and why we all need to look after them better".
Cornwall Wildlife Trust encourages members of the public to record any spider crab sightings, including those in larger groups or aggregations, via their ORKS app or online at www.erccis.org.uk/share-sightings