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 major storm of the season. Storm Austen named. . Weather Videos. Tuesday 20 October 2026
On the left, WindRadar shows a storm system over the UK with strong winds. On the right, high waves are crashing against a sea wall. A warning symbol indicates a storm.
Weather VideosTuesday 20 October 2026

Storm Austen named

First major storm of the season
South-east saw a record-breaking drought. Rain coming but not enough. . . Thursday 15 October 2026
Split graphic showing yellow rainfall deficit areas across the UK and Ireland beside a dry, parched landscape with two people walking.
Thursday 15 October 2026

Rain coming but not enough

South-east saw a record-breaking drought
Former hurricane to record storm. Isaias affecting Europe. . . Wednesday 14 October 2026
WindRadar shows a powerful storm system south-west of Iceland. Red and purple colours indicate extreme wind speeds. Arrows show the direction of rotation, whilst a windsock symbol warns of a storm.
Wednesday 14 October 2026

Isaias affecting Europe

Former hurricane to record storm
All weather news

This might also interest you

Bright and warm conditions take hold. Spring-like outlook. . . Thursday 23 April 2026
Split UK map showing warm temperatures up to 21 degrees in orange on the left and clear sunny conditions with temperatures from 12 to 18 degrees on the right, with sun icons across the country.
Thursday 23 April 2026

Spring-like outlook

Bright and warm conditions take hold
Super Typhoon Bavi threatens Taiwan. Up to 1,000 mm of rain. . Weather Videos. Wednesday 8 July 2026
The image shows an intense tropical cyclone over the western Pacific, east of Taiwan and the Philippines. The centre of the system is depicted as a light purple and white vortex with a clearly visible eye, surrounded by a ring of red and orange areas indicating the strongest wind speeds. A white arrow marks the typhoon’s predicted track towards the north-west, in the direction of Taiwan. To the west of the storm lie the Philippines, with the cities of Manila and Cebu; to the north of these lies Taiwan, with Taipei. Further west, the Chinese coast, including Hong Kong, and parts of Vietnam can be seen. The coloured wind map shows predominantly green areas outside the storm’s core, indicating significantly weaker winds. White streamlines illustrate the typhoon’s anti-clockwise circulation in the Northern Hemisphere. The highest wind speeds are concentrated around the eye of the cyclone.
Weather VideosWednesday 8 July 2026

Up to 1,000 mm of rain

Super Typhoon Bavi threatens Taiwan
A stormy week in the skies above. Your weather - Your shots. . . Sunday 30 August 2026
Split image showing lightning branching beneath dark storm clouds above rooftops on the left and an orange-pink sunset over a calm sea on the right.
Sunday 30 August 2026

Your weather - Your shots

A stormy week in the skies above
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