Swarm of Lion's Mane jellyfish off coast in Cornwall, UK

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Hundreds of giant venomous jellyfish have turned up at the Cornish coast in their search for food. Skip related content
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The Lion's Mane jellyfish, or Cyanea capillata, have a sting which can cause muscle paralysis, leading to suffocation and heart attacks.

The swarm of newcomers was first discoverd by diver Andy Pearson, who was surrounded by more than 200 of them while looking for basking sharks at Sennen Cove, Coverack Cove and Kynance Cove in southern Cornwall.

He also saw groups of the smaller and rarer blue jellyfish, which carry a nasty sting too.

Although he described the sight as "spectacular", Mr Pearson warned fellow divers and swimmers of the danger.

He said: "Usually there will be one or two but the jellyfish were literally everywhere in the water. It was worrying.

"Swimmers really need to be careful because the Lion's Mane can give a potent sting."

Ruth Williams, of the Cornwall Wildlife Trust, said: "It's unusual to get them in such massive swarms in Cornwall."

She also said swimmers must be careful and should stay "well clear of their trailing tentacles".

A spokesman for the Royal National Lifeboat Institution said they were aware of the danger and advised beach users to take care.

The Lion's Mane is one of the largest species of jellyfish. While their sting itself is not lethal, their tentacles are covered in stinging cells which can cause blisters and severe muscular cramp, affecing the respiratory system and heart function.

The creatures, which can reach up to 10ft long, are normally found further north in the colder Arctic and northern Atlantic oceans, but the freezing winter has made the southern seas cold enough for them.
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