Large numbers of Portuguese Man O' War spotted on UK beaches

Erin O'Neill By: Erin O'Neill
Date posted: 21 October 2019

Recent reports show large numbers of Portuguese Man O’ War washing up on UK beaches, with more than 60 being found on one stretch of beach in West Cornwall just today.

© Friends at Portheras Cove

Because a stranded Portuguese Man O’ War looks a bit like a deflating purple balloon with blue ribbons attached, children may find it fascinating.

Dr Peter Richardson,
Head of Ocean Recovery
© Friends at Portheras Cove

While these fantastical looking creatures might resemble a kind of jellyfish, they are actually a floating colony of hydrozoans – a group of tiny marine organisms living together and behaving collectively as if one animal.

They have a distinctive purple float that is visible on the water’s blue surface, with tentacle-like ‘fishing polyps’ that hang below; these can be tens of metres in length.

Look but don’t touch! They have a powerful sting that is excruciatingly painful, and in some cases deadly. Even Man O’ Wars that have washed up on the shore can deliver their painful sting, so take care to steer clear and to keep pets and children away.

“It’s the tentacle-like polyps that can give an agonising and potentially lethal sting,” says MCS jellyfish expert Dr Peter Richardson.

“Because a stranded Portuguese Man O’ War looks a bit like a deflating purple balloon with blue ribbons attached, children may find it fascinating.”

“It’s well worth making sure you know what these animals look like and that no one picks them up. We would like people to report any sightings of Portuguese Man O’ War to our website so we get a better idea of the extent of the strandings”.

If you do spot one, you can report your sighting to us here.

Recent reports show the creatures washing up in Cornwall, Devon, and Wales in the past few weeks. The last time there was a major stranding event was in 2017 when hundreds of thousands washed up in the South West of the UK.

Man O’ Wars normally live out in the open ocean and only wash up on UK beaches when blown in by persistent south westerly winds.

If you are unlucky enough to get stung, the NHS has provided a guide on treating jellyfish and other sea creature stings.


Actions you can take

  1. Download our Jellyfish Guide

Did you know?…

Over 1,000 marine wildlife sightings were reported to MCS last year

Over half a million people have voiced their support for ‘marine protected area’ designation in the UK through our campaigns

Last year, over 300 Seasearch divers spent over 8 weeks surveying underwater

Want to know more about Jellyfish?

Jellyfish Guide Find out more about UK species.

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