Sea lice levels exploded last summer. This year, the warning signs are already here - and they’re showing up early.
Sea temperatures across Norway are running well above normal for this time of year. In many cases, they’ve already surpassed the levels that preceded last year’s historic lice outbreak. Climate forecasts are confirming what farm data is starting to suggest: this could be another difficult lice season, and it may arrive sooner than expected.
Let's look at what the early indicators are telling us, why marine heatwaves matter, and how this year’s pressure isn’t just biological - it’s financial, strategic, and regulatory.
Last summer, Northern Norway experienced the most severe sea lice outbreak ever recorded.
At the peak of the outbreak in August, sea surface temperatures reached nearly 16ºC, far above the typical 13ºC seasonal average. By then, treatment infrastructure was already stretched. Many of the large-capacity well-boats were committed to southern operations. As lice numbers surged, companies raced to catch up, but the response came too late.
Manolin’s models showed lice counts during July–September were four to five times higher than any of the previous five years, sustained for weeks. Even with a 60% increase in treatment activity during that period, the outbreak stayed ahead of the system.
The result: delayed growth, higher costs, and widespread operational strain.
Twelve of Norway’s thirteen production zones are already seeing record-breaking sea temperatures for April. In several areas, the water is warmer than it was at this time last year.
That matters because lice development accelerates in warmer water. The seasonal window for reproduction is opening earlier, and likely lasting longer. Climate researchers are echoing these concerns. The Nansen Environmental and Remote Sensing Center has issued marine heatwave forecasts that include:
High-likelihood heatwaves in the North Sea during April–June
Sustained warming in the Barents Sea from July–September
That forecast directly overlaps with key farming regions in the north - the same regions hit hardest last year. If conditions play out as predicted, lice pressure could once again reach levels that overwhelm treatment systems.
Sea lice management doesn’t happen in a vacuum. It’s shaped by farm economics, and right now, those economics are tightening.
Spot prices for salmon are around 75 NOK/kg, roughly 50 NOK below where they were a year ago. With thinner margins, even one additional round of lice treatment can make a measurable dent in profitability.
Strategic shifts are already visible:
Mowi recently announced the sale of its feed division.
Nova Sea and several smaller operators have been acquired.
Ongoing speculation about Grieg’s future adds to the broader sense of industry restructuring.
These moves point to a sector under pressure - one where capital is being reallocated and operational risk is being reevaluated. A poorly timed lice outbreak this year wouldn’t just affect biology. It would affect balance sheets.
Norway’s proposed shift toward emissions-based licensing adds another layer of complexity.
In the coming years, companies won’t just be measured by how much fish they produce. They’ll be assessed by the environmental footprint they leave - and that includes sea lice pressure and mortality rates.
The implications are long-term, but the transition is already underway. Farms are rethinking how they measure success and how they prioritize investments. And in a year like this, when lice pressure may be rising and treatment costs are rising with it, staying ahead of the curve is no longer optional.
No one can predict the full arc of this season. Water temperatures may stabilize. Environmental models may shift. But the early signals are clear, and the window to act is narrow.
This year’s lice pressure isn’t just an environmental concern. It’s a convergence of biology, economics, and policy - and farms that respond early will have more room to maneuver when challenges peak.
As always, no model is perfect. But when directional signals start pointing the same way - rising sea temperatures, climate models, and historical trends all aligning - it’s time to take notice.
The season has already started. And decisions made now may define what happens three months from now.