Barrel Jellyfish Surge Shocks British Shores

As of November 3rd, 2025, the British coastlines have witnessed a remarkable surge in barrel jellyfish sightings, with a staggering 230% increase compared to the previous year. This startling trend has been documented in the Marine Conservation Society's annual wildlife sightings report.

The report reveals that the barrel jellyfish, known for its distinctive large size and frilly texture, has risen to become the second most spotted species, up from fifth place last year. Meanwhile, the ever-present moon jellyfish continues to reign as the most commonly sighted species, accounting for 24% of the 1,327 total jellyfish sightings recorded across the UK and Ireland.

Interestingly, the report also highlights a significant increase in Mauve stinger blooms, also known as the purple-striped jellyfish. These blooms have reached their highest levels on record, marking a 31% rise from the previous year.

The surge in barrel jellyfish sightings is particularly intriguing, as it may be linked to warmer sea temperatures and changing ocean currents, according to Anna Bunney, the citizen science programme manager at the Marine Conservation Society. She emphasizes the importance of public sightings in helping scientists track these dynamic changes in coastal ecosystems in real-time.