Home
Weather Dublin
WeatherRadar
RainfallRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
    Home / Editor's Pick /

    Marine heatwaves: Jellyfish thrive in the UK

08:00
11 November 2023

Marine heatwaves
Jellyfish thrive in the UK

Crystal jellyfish (Aequorea victoria) often found in warmer waters.
Crystal jellyfish (Aequorea victoria) often found in warmer waters. - © picture alliance

Jellyfish sightings in the UK have soared 32% in the last year, due to our warming waters.

From October 2022 to September 2023, jellyfish sightings have soared 32% along UK coasts. The bulk of these sightings have been on the UK's Atlantic west coast, particularly around Cornwall and Wales.

Species such as barrel jellyfish, Lion's mane, Portuguese man o' war, moon and compass jellyfish have all been spotted, including crystal jellyfish, which are more commonly known to warmer waters.

The hot weather in recent months, particularly in June, created marine conditions for the species to thrive in the UK.

Marine heatwaves

We're all familiar with the idea of a heatwave, but a marine heatwave is much less visible yet equally concerning. Marine heatwaves are periods of unusually warm ocean temperatures that can last anywhere from days to months.

Warmer waters due to marine heatwaves can severely impact marine ecosystems, creating nutrient-deficient "ocean deserts" that make it challenging for marine life to survive.

These temperature spikes are linked to a range of disruptions, from coral bleaching and altered fish migration patterns to the degradation of vital kelp forests along the coast.

That being said, it has led to a positive influx of new jellyfish species to UK coasts, though this could have knock-on implications on the marine ecosystem.

Scientists are unsure if the new species are a short-term result of the marine heatwaves, or a longer-term shift in their northward range as waters warm on average.

Oceans reach record high temperaturesread more
Weather & Radar editorial team

More on the topic

First widespread frost of the season. Freezing evenings. . . Wednesday 11 November 2026
Temperature map showing -3°C near Cardiff, -2°C in Dublin, -1°C in Glasgow and Liverpool, and 2°C near Aberdeen and London, with a blue thermometer.
Wednesday 11 November 2026

Freezing evenings

First widespread frost of the season
Brazil: A spring full of storms. Rain and flooding. . . Friday 13 November 2026
Split. On the left, a weather map of Brazil showing clouds, rain and lightning. On the right, a thundercloud
Friday 13 November 2026

Rain and flooding

Brazil: A spring full of storms
Storm hits the Iberian Peninsula. Hurricane-force gusts. . . Wednesday 11 November 2026
WindRadar showing a storm warning symbol and areas of strong winds over Portugal, southern Spain and Morocco.
Wednesday 11 November 2026

Hurricane-force gusts

Storm hits the Iberian Peninsula
All weather news

This might also interest you

Historic Storm Éowyn arrives. On this day.... . . Saturday 24 January 2026
Split image showing a person in a yellow jacket struggling against strong winds and heavy rain on a street at night on the left, and an Irish wind forecast map on the right with red and purple shading, gusts up to 75 mph, and a wind warning icon, divided by a curved white line.
Saturday 24 January 2026

On this day...

Historic Storm Éowyn arrives
Storm Chandra makes impact. Severe gales & heavy rain. . . Tuesday 27 January 2026
Split image showing strong winds over the UK on a forecast map and widespread rain and snow on a weather radar map.
Tuesday 27 January 2026

Severe gales & heavy rain

Storm Chandra makes impact
New records for England and Wales. Broken again tomorrow?. . . Thursday 25 June 2026
Temperature map of southwest Britain on 25.06 showing extreme heat across southern Wales and southwest England, with Bute Park in Cardiff highlighted at 34.2°C and Yeovilton at 36.4°C amid widespread deep red heat zones.
Thursday 25 June 2026

Broken again tomorrow?

New records for England and Wales
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy Policy Legal info Accessibility statement

Services

Uploader

Socials

facebooktwitteryouTubelinkList