Invading our coastlines, swarms of jellyfish that can paralyse swimmers

Invading our coastlines, swarms of jellyfish that can paralyse swimmers

By DAILY MAIL REPORTER

Last updated at 8:47 AM on 15th June 2010

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Swarms of giant venomous jellyfish have invaded waters off the British coast.

Swimmers are being warned to be on the lookout after scores of Lion's Mane jellyfish were spotted in the sea off Cornwall.

The jellyfish, which can grow up to 8ft in diameter, are a danger because their toxic sting can cause muscle paralysis, leading to suffocation and heart attack.

Danger: Swarms of giant Lion's Mane jellyfish have been spotted off the Cornish coast

They are usually found further north, in the Arctic and northern Atlantic oceans, but the freezing winter means the seas further south have become sufficiently cold.

It is also thought that flourishing plankton - a key food source for jellyfish - have lured the creatures.

The invasion was spotted by Andy Pearson, who was surrounded by more than 200 Lion's Mane jellyfish while looking for basking sharks at Sennen Cove, Coverack Cove and Kynance Cove in southern Cornwall.

The diver also saw swarms of the smaller and rarer blue jellyfish - which also carry a nasty sting.

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

He added: 'Lion's Mane jellyfish don't normally travel as far south as Cornwall but the cold winter has made the sea temperature drop and these jellyfish are most at home in cold water. They feed on plankton and there's a lot around at the moment too which has probably attracted them.'

Deadly: Lion's mane jellyfish can grow up to 8ft in diameter and their toxic sting can cause muscle paralysis, leading to suffocation and heart attack

Swarm: The invasion was spotted by a man looking for basking sharks in southern Cornwall who was surrounded by more than 200 of the jellyfish

But he sounded a warning to anyone heading to see the creatures.

'It was really spectacular to see so many jellyfish so close but we had to be careful to avoid getting stung by the tentacles,' he said. ' Swimmers really need to be careful because the Lion's Mane can give a potent sting.'

The tentacles of the Lion's Mane - one of the largest species of jellyfish - can reach up to 10ft long and are covered in stinging cells which can cause blisters and severe muscular cramp, which can affect the respiratory system and heart function. The sting itself is not fatal.

Ruth Williams, of the Cornwall Wildlife Trust, also warned swimmers to take care.

She said: 'It's unusual to get them in such massive swarms in Cornwall.

'They are one of the more dangerous jellyfish and their tentacles are incredibly long.

'They can give a nasty sting. I would warn swimmers to 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 be careful.

Read more: http://www.dailymail.co.uk/sciencetech/article-1286652/Invading-coastlines-swarms-jellyfish-paralyse-swimmers.html#ixzz0rC4wB4Rt