Salmon and Jellyfish Don’t Play Well Together

Jellyfish Attacks Prompt the Culling of 200,000 Fish

Salmon prices are expected to rise as the fish farming industry continues to face obstacles of the sea creature sort. Jellyfish blooms are a growing concern for salmon farmers from Ireland, to Norway, to Scotland and have contributed to tight supplies of the sought after protein in recent years. 

What Are the Challenges Faced by Salmon Farms?

Fish farms are an integral part of food security. Farming offers reliable production methods that experience fewer supply fluctuations as opposed to fishing, which is often at the mercy of weather and ecosystem imbalances.  Yet, like all mass produced livestock, fish farms face their own unique challenges when it comes to the transmission of disease and ecosystem impact. Salmon farms in particular have been prone to bacterial infections resulting in the culling of hundreds of thousands of fish.

In March of 2024, the Norwegian company, Cermaq, was forced to cull 900,000 salmon as they were unable to improve the health conditions for their fish and feared the spread of infection. In January of 2025, Scottish salmon farms culled 200,000 fish for the very same reasons. However, bacteria alone is not the culprit. The underlying issue is an increased amount of jellyfish, particularly the barbed wire jellyfish, attacks on fish farms.  Salmon suffering lacerations from these attacks are prone to bacterial infections which are easily transmitted to other fish in a farm setting where they are in closer proximity to one another.

Market Impacts of Salmon Population Decline

The jellyfish problem is nothing new. As far back as 2002 fish farms in the Northern Atlantic were noticing a rise in mass die offs and suspecting jellyfish blooms as the culprit. Jellyfish, which are a highly resilient family of organisms, have had fewer predators and more abundant food sources as of late which appears to be compounding the situation. For the multibillion dollar industry, establishing new protection barriers is crucial to continued development. 

Salmon farming has experienced a supply decline for two straight years, while global demand has steadily increased making it the most popular and profitable fish. Salmon is considered the most efficient food system in that it offers the best feed input to edible yield ratio compared to other animals raised for food like cows, lambs or pigs. Developing nations have shown an increased interest in the protein retaining food source. And, large markets like the U.S. and China have also experienced a rise in demand for the fish that is typically appreciated for its health benefits.

Current decline has turned buyers attention towards Chile who has become the world’s second largest exporter of farmed salmon. Yet, even Chilean farms have faced bacterial challenges as well as shipping disruptions due to shipping container shortages that transport frozen filets north. If jellyfish continue to pose a substantial threat, consumers could also look to other fish options including trout, which is praised for its nutritional benefits and efficiency, or tilapia which has made a substantial comeback after Covid related declines in farm populations. 

Can Technology Save the Salmon Farming Industry?

Dense populations of salmon found in farms coupled with slightly warmer water temperatures has created a prime environment for jellyfish in the Atlantic. They are not going away. Scotland has already invested $1 billion in the welfare of their salmon raised in farms. Part of this includes researching jellyfish and their impact on salmon as well as developing practical responses to avoid interactions between the two.

Understanding where and why jellyfish populations are exploding could help farmers know where farms will do best.  Monitoring blooms could also help farmers respond before the two species interact with each other 

In Norway, a tech company which is already using electrical pulse machines to prevent sea lice from attaching to salmon has already begun adding a feature that uses the same electrical innovations to trigger jellyfish to release their venom making them harmless to surrounding fish for days at a time. The technology so far seems to be a chemical free, antibiotic free method of ensuring a healthy and safe environment for fish while still allowing them to coexist with jellyfish. Perhaps, they will play well together in the long run.