Farmed salmon escape from Mowi in Frøya threatens wild populations in Norway

On September 17, an unknown number of farmed salmon escaped from Mowi in Frøya, with over 1,500 fish recaptured so far, suggesting a significant escape akin to Lerøy’s earlier incident which involved 13,500 fish. The recently escaped Mowi salmon have now found their way into the rivers of Trøndelag, where they may breed with the few remaining wild salmon and with Lerøy’s fish. Although the offspring may struggle to survive long term, they initially outcompete their wild counterparts.

Repeated escape incidents and the mixing of farmed salmon threaten thousands of years of evolutionary adaptation. Furthermore, Lerøy’s fish were confirmed to be sick with bacterial kidney disease (BKD), detected in one captured fish in the Gaula river. This infectious and potentially lethal disease poses risks to wild salmon populations.

As if the existing sea lice problems on the western and central coasts weren’t enough, this summer has seen an extreme outbreak of sea lice in northern Norway, attributed to increased production in open cages combined with rising sea temperatures. Fish farmers, caught off guard, claim they did not predict the temperature rise despite the hot summer.

Current research indicates no significant warming expectations for northern regions, contradicting the assumption that external factors are to blame. Instead, it is the operational model using open cages that is the core issue. With around 450 million fish residing in open cages off the coast, the industry must transition to zero-emission solutions to curb sea lice and escapes.

The government’s recent Nature Report outlines these challenges but fails to provide solutions. It is crucial that the upcoming Aquaculture Report addresses these issues; otherwise, the wild salmon populations are at severe risk. The fishing minister has a clear mandate: Emphasize zero emissions to ensure the future of both wild and farmed salmon.