What Should I Do If I’m Stung By A Jellyfish In The UK?

I blinked, and suddenly, it was the middle of June. I haven’t made a single summer plan yet. Luckily, if you’re like me, there’s always Britain’s beaches to fall back on whenever I need a quick holiday boost. Just keep an eye out for the jellyfishokay?

Thanks to rising sea temperaturesthere are ever-increasing reports of jellyfish popping up in British and Irish waters—there were even jellyfish recently spotted in the Mersey! The warmer waters around the UK now make it far more attractive for reproduction, which only means swimmers must be ever more vigilant.

“Rising sea temperatures are having a direct impact on marine life in all kinds of ways. Warmer waters can expand the habitat of marine species such as stingrays and jellyfishallowing them to thrive in our coastal regions—areas that would have previously been too cold for them,” said Genevieve Watson, Biologist and Water Data Consultant at KISTERS.

“This is something that feels particularly noticeable as we are seeing these changes happening within our lifetimes. Few of us will look back on our childhood and remember ever seeing a stingray or jellyfish in the water at the seaside, but actually, for our children and grandchildren, this could be an increasingly common sight.”

Are jellyfish dangerous?

While some fatal jellyfish do exist, the ones bopping around British waters likely aren’t that deadly to humans. But you still don’t get too close to these peculiar creatures—their sting can and will hurt you and ruin your beach trip.

Depending on the type of jellyfish you encounter, you may experience a variety of reactionsfrom an itchy rash and swelling to nausea and difficulty breathing. Not something you want to deal with in the middle of the sea. So if you spot one, calmly swim away and alert others.

What jellyfish are there in Britain?

There are six main types of jellyfish (and two jellyfish-like species) living off the coast of the UK:

Barrel jellyfish: A large, mushroom-shaped jellyfish (growing up to 1m in diameter) with a mild sting. It can be either white, pale pink or blue, yellow, and is fringed with purple markings.
Blue jellyfish: Growing up to 30cm, they’re like a small lion’s mane jellyfish with a blue bell—but a yellow variant also occurs in UK waters. Not a bad sting, but still best avoided.
By-the-wind-sailor: Not a jellyfish, but a floating colony of hydrozoans. They only grow up to 10cm long and have a very mild sting, but they often appear in swarms. They are blue-purple, with a sail-like top and small tentacles underneath.
Compass jellyfish: Named after its brown V-shaped markings (like a compass), it has an umbrella-like bell and long, thin tentacles; it can deliver a painful sting.
Lein’s man else: These big (usually 50cm) reddish-brown jellyfish, with hair-like tentacles, are known for their painful stings.
Mauve stinger jellyfish: Deep purple (like its name suggests) and covered in warts, it has a painful sting.
Moon jellyfish: With its transparent, dome-shaped bell, horseshoe-shaped purple rings (aka gonads), and short hair-like tentacles, this jellyfish has a mild sting.
Portuguese man o’ war: Again, not a jellyfish, but likely the most famous among them. Although rare, and rarely deadly, it can be extremely painful when stung by one. Keep an eye out for its trailing tentacles (often many metres long), bluey-purple colour and distinct ‘mohawk’.