Not only have there been an abnormal number of washed-up barrel jellyfish along Irish shores recently, but they are also showing up in unusual locations, experts say.

With summer just around the corner, many people opt to take to the waters for their first dip of the season. But swimmers might unexpectedly encounter the barrel jellyfish.
The jellyfish is no stranger to Irish shores but is showing up in unusual areas. Swimmers in Irish waters are urged to watch out for the rather uniquely shaped jellyfish, despite it being harmless.
- Not only have there been an abnormal number of washed-up barrel jellyfish along Irish shores recently, but they are also showing up in unusual locations, experts say.
- Unusually large numbers of jellyfish spotted on Irish shores – sightings baffle scientists
- Awareness is critical – getting to know the species
Unusually large numbers of jellyfish spotted on Irish shores – sightings baffle scientists

- Not only have there been an abnormal number of washed-up barrel jellyfish along Irish shores recently, but they are also showing up in unusual locations, experts say.
- Unusually large numbers of jellyfish spotted on Irish shores – sightings baffle scientists
- Awareness is critical – getting to know the species
While the barrel jellyfish, also known as the cauliflower jellyfish, are not unknown in Ireland, they are generally spotted in Ireland’s southeastern waters. Yet, recently the sea creatures have been spotted as far as Cork.
A total of 96 barrel jellyfish sightings have been recorded by the National Biodiversity Data Centre, where they have noticed a significant increase from Lough Foyle in the north to west Cork in the south.
The unusually shaped and relatively large species of jellyfish is said to be harmless, but open-water swimmers are urged to keep an eye out, as they might encounter a few of these creatures in the wild – which might be a shock to some.
Despite their intimidating appearance, the barrel jellyfish pose little threat to humans as their sting is relatively mild. However, spotting them is easy as they appear translucent, look like cauliflower, and boast eight tentacles.
University College Cork scientist Dr Tom Doyle said the cauliflower-shaped (barrel) jellyfish – so named because they resemble the vegetable – can weigh up to 25 kg and “look scary” but don’t really sting, which should put swimmers’ minds at ease.
The sightings are occurring almost halfway around the Irish coastline, which is very unusual. Doyle added, “The reports of their geographical spread began early in the year when we had 15 washed up in 30 days on our beaches,” leaving scientists intrigued.
Awareness is critical – getting to know the species

It seems this isn’t the only unusual thing to happen in Irish waters. In fact, in Galway Bay, there has been an increase in lion’s mane jellyfish, known for their long tentacles and venomous sting.
According to local swimmer Paddy McNamara, this jellyfish was rare two years ago and is now considered relatively common in Galway Bay. In addition, barrel jellyfish have also been spotted in Galway Bay and Dublin Bay, defying previous patterns.
In an effort to dispel fear and misconception, Dr Tom Doyle has taken it upon himself to educate the public at Bloom Festival in Dublin this June and to showcase beauty and ecological importance of the jellyfish.
Dr Doyle plans to collaborate with botanical artist Shivaun Doherty and designer Adam Whitbourn to create a jellyfish garden funded by Science Foundation Ireland.
Visitors will have the chance to observe various jellyfish in a mesmerising aquarium, giving them a different perspective on the creatures.
As jellyfish continue to make their presence felt along the Irish coastline, scientists and nature enthusiasts eagerly observe the phenomenon and hope to unravel the mysteries behind these ongoing sightings.