Lowdown on jellyfish

Emma Chaplin
, 24 July 2023
Lowdown on jellyfish
Moon Jellyfish © Paul Naylor

Sarah Ward, Living Seas Officer

This June and July we’ve seen a bloom in jellyfish numbers along the Sussex coast. This often happens at this time of year, and comes as no surprise given the spell of warm, settled weather we’ve had. Jellyfish eat plankton – they will follow their source of food but are drifters so are not able to swim directionally. This is why they drift in on currents and can sometimes be found in large numbers when they’ve all drifted together, and may even get washed up on the beach.

Compass Jellyfish © Paul Naylor
Compass Jellyfish © Paul Naylor

On a recent Shoresearch survey in Bexhill-on-Sea, we saw large numbers of Blue Jellyfish (Cyanea lamarckii) and Moon Jellyfish (Aurelia aurita). They had all come in on the low tide and were mostly washing around in tide pools; there were a few that were beached, which we gently moved back to the water (ensuring not to touch them with bare hands!).

There are six species of jellyfish (and two jelly-like relatives) which can be seen on UK coasts. All these jellyfish are able to sting so it is best to be cautious. If you do get stung, the best thing to do is remove any stingers still attached (a credit card is good to use to scrape them off – avoid using your fingers as you’ll end up with stung fingers as well) and rinse with water. If you have vinegar to hand, this will help to neutralise the sting. For most people the pain is relatively milk (akin to a nettle sting for most UK species) and should subside within a few hours; over-the-counter painkillers or antihistamines can help. Medical advice should be sought if you have a severe reaction.

Remember that jellyfish can still sting when they’re dead, so it’s best not to touch if you see one washed up on the beach. Wearing an exposure suit (eg a wetsuit) in the sea will protect you from possible jellyfish stings while swimming.

Blue Jellyfish at Saltdean © Kevin Pope
Blue Jellyfish at Saltdean © Kevin Pope

Have you seen a jellyfish? Here’s our guide to UK jellyfish and other jelly-like creatures.

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Comments

  • Rachael:

    I thought Moon Jellyfish don’t sting?

    28 Jun 2024 06:51:00

  • Sussex Wildlife Trust:

    Moon Jellyfish's sting is very mild and most people have only a slight reaction to it if anything at all.

  • Polegate Paul:

    Saw jellyfish today and yesterday at Winchelsea Beach. I’m no good with types, but I’m told I’d seen a box jellyfish, because it resembled a four on a dice.

    25 Aug 2025 22:24:00

  • Maniebot:

    Thanks for your wonderful sight! Re Polegate Paul – really hope not a box jellyfish!!! I’m Australian, swim near daily in Brighton and today (6/Sept) I became incredibly itchy whilst swimming and lasted a while afterwards. Nothing extreme, but never had anything like that before. I was doing some reading (asking ChatGPT🥺) and there is mention of hydroids as likely culprit given the kelp mats washing along from recent weather. Could this be the likely cause? :)

    06 Sep 2025 13:54:00

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