Multi-million Norwegian project aims to tackle jellyfish threat

In 2023, unusually high numbers of "pearl chain" or string jellyfish in Norwegian waters led to millions of farmed fish deaths. The JellySafe project aims to prevent this happening in future, with NOK 35 million in funding.
"It’s unusual how little we know about something that has had such a significant impact," says marine scientist and JellySafe lead researcher Tina Oldham.

"It’s unusual how little we know about something that has had such a significant impact," says marine scientist and JellySafe lead researcher Tina Oldham.

Photo: Erling Svensen / Havforskningsinstituttet (The Norwegian Institute of Marine Research).

Recent observations have shown a marked increase in "pearl chain" or "string" jellyfish sightings along the Norwegian coast, particularly from October to January 2023 - an influx which led to the deaths of millions of farmed fish.

Last year, Norway recorded its highest-ever mortality rate of sea-phase salmon, and registered over 100 million salmon and trout deaths. Fish farmers up and down the country, including SalMar and Lerøy Seafood, reported that the "pearl chain" jellyfish, Latin name Apolemia sp., was one of the main culprits in the crisis.

However, until now little research has been carried out on this jellyfish species and the risks it poses to aquaculture.

Now, a team of researchers led by the Norwegian Institute of Marine Research are aiming to address these knowledge gaps and prevent future jellyfish threats, through the JellySafe project, which has received nearly 35 million kroner (USD 3.3m / EUR 3.1m) in funding from Norway's Seafood Research Fund (FHF).

“The whole point of research is to investigate things we don't know, and the pearl chain jellyfish situation is unique. It’s unusual how little we know about something that has had such a significant impact," explained marine scientist and lead researcher Tina Oldham in a press release.

"We lack both the knowledge and infrastructure to prepare for such harmful plankton,” she added.

What are pearl chain jellyfish?

<div class="paragraphs"><p>An accumulation of Apolemia jellyfish observed in Vågen, Stavanger.</p></div>

An accumulation of Apolemia jellyfish observed in Vågen, Stavanger.

Photo: Dugnad for havet / Norwegian Insitute of Marine Research.

Sometimes also referred to as "string jellyfish", Apolemia is a colony organism composed of smaller individuals that can grow up to 30 meters long, and has stinging cells that harm fish. The jellyfish are found in the pelagic zone, from the surface until a depth of 1000 metres, and are common in the Pacific, Mediterranean and Atlantic Oceans.

However, when encountering waves, turbulence, and physical barriers such as net pens, jellyfish colonies break apart, and these smaller pieces can infiltrate fish farms.

At the time of the jellyfish influx during last autumn, Norwegian researchers began gathering data about both the affected farmed fish and the jellyfish causing the damage. Samples were taken at the Institute's research station in Austevoll, and initial projects to find mitigation measures were launched.

JellySafe to develop early warning system and identify best ways of tackling jellyfish blooms

JellySafe will build on this work, involving a wide range of experts including engineers, mathematicians, oceanographers, fish health researchers, zooplankton ecologists, and molecular biologists.

According to the research team, the project will explore everything from the biology of the jellyfish and how it is influenced by biological forces, to developing strategies and measures to address the threat and ensure the information reaches those who need it.

The goals include developing a national early warning system, distribution models, and strategies to prevent and mitigate Apolemia influxes, identifying causes of jellyfish blooms, testing methods of preventing and removing the jellyfish from unsecured pens, and creating accessible, web-based tools with guidelines and updated knowledge on Apolemia.

The researchers are also calling on Norwegian citizens to report sightings of the jellyfish and document these with photographs, and urges the public to report sightings even if they occur in the same place multiple times.

Led by the Norwegian Institute of Marine Research, the project incorporates partners SINTEF, Akvaplan-niva, NIVA, UiB, Patogen, NCE Aquaculture, and Åkerblå.

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