Norway’s sea lice data in 2025 showing signs of another difficult season.
Sea lice levels across Norwegian salmon farms are developing in line with last year’s record-breaking season, and in some cases are already worse, according to analysis from aquaculture technology company Manolin.
The company’s models show that mobile lice pressure in 2025 is tracking at unprecedented levels, while female lice counts remain persistently high and close to what farms faced at the same point in 2024. Warmer waters have also returned, accelerating the lice lifecycle and narrowing the window for effective intervention.
Prices shaping treatment behaviour
Earlier this year, Manolin’s Observer report forecast lice trends using historic farm data, environmental variables and treatment patterns. Founder Tony Chen now says the model missed one key input: global salmon prices.
“The price of salmon has become a quiet driver of treatment strategy. With tighter margins, farms are under pressure to lower costs, and treatments, especially large-scale ones, are an easy target,” Chen said.
Export prices for Norwegian salmon have fallen earlier and faster in 2025 compared with recent years, according to Statistics Norway. This has coincided with more fragmented treatment strategies across farms.
Fragmentation in treatments
Manolin’s analysis shows that while the number of cages being treated is increasing, interventions are shorter, smaller and more frequent. Large-scale, synchronized delousings have declined, while partial site treatments have risen.
This shift has led to higher lice levels prior to treatment compared with previous years, with farms delaying or scaling down action. “Delays by one operator increase the reinfestation risk for everyone,” Chen noted.
Chen draws parallels with the Prisoner’s Dilemma in game theory, where farms face an individual incentive to delay treatment in the hope of better timing, even though collective early action would reduce regional lice loads.
“With EBIT/kg figures across the industry close to break-even, the instinct to delay or reduce treatments isn’t greed, it’s necessity. But the higher the lice counts before action, the less effective treatments become,” Chen said.
Options for coordination
Manolin suggests that coordination between farms, social pressure through reputation, and regulatory frameworks such as Norway’s traffic light system can help align incentives and reduce regional pressure.
The company points to recent work with Cargill and Hofseth where tailored predictive models guided treatment timing, leading to improved outcomes.
Chen concludes that sea lice management remains a regional challenge with shared consequences: “The tools exist. The models work. The question is whether farms can afford, not just financially but operationally and politically, to act like part of a shared system.”
