Researchers Urge UK & Irish Fishermen to Report Jellyfish

String Jellyfish are now reaching North Atlantic coast as researchers call on UK and Irish fishermen to report sightings

A jellyfish species that previously caused major stock losses at salmon farms in Northern Norway is once again moving northward, prompting an urgent call for assistance from fishermen across the North Atlantic, including Ireland, the United Kingdom and the Faroe Islands.

In 2024, outbreaks of string jellyfish (Apolemia sp.), a long, rope-like colonial species transported by ocean currents, caused extensive damage at several aquaculture sites in Northern Norway. Fish in multiple pens were injured or killed. At one location in Øksfjord, Finnmark, researchers are currently testing brush-wall barriers as part of a wider set of measures designed to limit the impact of these jellyfish.

“We urgently need observations from fishers in Scotland, England and the Faroe Islands,” said Tina Oldham, project leader at the Institute of Marine Research.

String jellyfish have previously been responsible for killing millions of salmon during winter months. Researchers believe the species travels along the North Atlantic current, passing west of Ireland and between the Faroe and Shetland Islands before reaching Norwegian waters.

Tone Falkenhaug of the Institute of Marine Research said inline, “Even if you are not sure what you saw, please report it. Every sighting helps.”

To assist identification, researchers have produced a short English-language animation with Faroese subtitles. The video, along with download options, is available on Vimeo. Sightings can be reported at dugnadforhavet.no.

New Protection Measures Under Trial

Several approaches are being tested to protect salmon farms from jellyfish incursions, including brush-wall barriers, electrical barriers, bubble curtains and shielding skirts. Oldham noted inline that “even the most effective protective measure is only helpful if we have early warning that jellyfish are coming”.

How Irish, UK, Faroese and North Atlantic Fishermen Can Assist

Fishermen in Scotland, England, Shetland, Orkney, the Faroes, Ireland and across northern Britain are asked to:

Watch for long, rope-like jellyfish or jellyfish fragments.
Photograph them where possible.
Report sightings through dugnadforhavet.no (English version available).
Include the position, date and a brief description.
Submit reports even when identification is uncertain.

These observations will support researchers in determining when, where and under what conditions string jellyfish appear.

About the JellySafe Project

The JellySafe project aims to understand and reduce the harmful effects of Apolemia sp. on Norwegian aquaculture, following three consecutive winters of damaging blooms that caused significant fish mortality and financial losses.

Current research focuses on potential mitigation techniques such as brush walls, electrical barriers, bubble curtains and lice skirts. The project brings together the Institute of Marine Research, Sintef Ocean, Akvaplan-niva, NIVA, the University of Bergen, NCE Aquaculture, PatoGen, Åkerblå and multiple aquaculture companies.

The initiative is funded by the Norwegian Seafood Research Fund (FHF), supported by the Institute of Marine Research and the University of Bergen. Its long-term objective is to create a reliable early-warning system for colonial jellyfish along the Norwegian coast and to develop practical solutions that improve preparedness for future outbreaks.