Unusually high sea temperatures in Norway are forcing salmon farmers to accelerate adaptation efforts as they battle a surge in sea lice infestations, highlighting growing climate-related challenges for the aquaculture industry.

The temperature spike, which arrived earlier than climate scientists and the Institute of Marine Research had predicted, has particularly impacted northern Norway's aquaculture operations, where farms were caught unprepared for the rapid proliferation of parasites. Several facilities were forced to conduct emergency harvests to contain lice outbreaks, according to Norwegian broadcaster NRK.

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The challenges worsened in September when approximately 10,000 salmon, totaling 20 metric tons, were found dead at a northern Norway site. Officials attributed the mass mortality to hydrogen sulfide release, a toxic gas formation linked to the season's abnormally high temperatures and stagnant water conditions.

Industry experts are now calling for comprehensive operational changes. Proposed adaptations include reducing fish density in sea pens, implementing earlier lice treatments, and developing new technologies -- measures that could impact profitability but are increasingly seen as necessary for long-term sustainability.

The situation has renewed debate over Norway's "traffic light system," which mandates production cuts in areas heavily affected by sea lice. Some producers in western Norway, through the PO3/4 Knowledge Incubator, have reopened legal challenges against these regulatory restrictions, arguing for alternative approaches to parasite management.

Solutions

In response to mounting biological risks, major producers are increasingly turning to land-based solutions.

Recirculating aquaculture system (RAS) are helping Norway's salmon farming industry maintain positive growth in the medium term amid growing biological challenges in sea pen production, according to the latest edition of Spheric Research's Land-based Aquaculture Report.

The report, which analyzed over 200 RAS post-smolt facilities globally, found that significant salmon producers like Norway and the Faroe Islands have insulated themselves from declining production thanks to their widespread embrace of land-based RAS technology over the last 10 years.

Norwegian aquaculture companies Mowi and SalMar have especially prioritized investing capital into large-scale RAS smolt and post-smolt facilities to supply their ocean net pen operations. While aquaculture scientists are still debating whether RAS produces healthier post-smolts, there is a broad consensus that minimizing grow-out time in the sea reduces fish mortality. 

Salmon producers are evaluating other solutions to reduce biological risks caused by rising temperatures, frequent sea lice infestations, and other climate change impacts.

According to Norwegian Seafood Council analyst Paul Aandahl, Norwegian producers are analyzing various technologies, such as using submersible pens to lower the fish beneath the sea surface, where the temperature is cooler and light exposure is reduced.

This could help mitigate problems related to heat and lice. Some are already implementing this method in southern Norway, but the analyst said it could become more widely adopted across the country.

Offshore farming, which is potentially another solution, is currently being evaluated in Norway, although the development of those projects has been temporarily put on hold in the country pending more clarification on the ground rent tax from the government, according to Aandahl.

Challenges affecting salmon farming have also contributed to boosting Norway's trout output. 

"Trout is more resilient to biological challenges than salmon, particularly in southern Norway, where farmers are increasingly switching from salmon to trout," noted Aandahl.