fish health

The sea lice situation in Norway

Sea Lice

Sea lice data are published on a weekly basis by Sea lice levels normally troughs in May/June and peaks in the fall. Remember that the max limit is 0.5 lice per fish (yellow line).

No county currently has above 0.2 lice per fish (which is the requirement for future growth in Norway). However, most sea lice per fish is found in Nord Trøndelag, Møre and Romsdal and in Hordaland (west Norway).



These are the average lice levels YTD.

Møre & Romsdal and Hordaland also have the highest sea lice concentration due to the high number of fish in the sea in these regions.



During a life-cycle, it is normal that the salmon must undergo sea lice treatments (a realistic ambition is 2 treatments per cycle). Treatments are costly and inhibits seawater production (reduced appetite and growth). The share of sites treated for lice is illustrated below.

Sea lice and treatments: 5  key reasons to pay attention
  1. One prerequisite for growth in Norway is that farmers keep sea lice levels below 0.10.
  2. Another prerequisite for growth is that the average number of treatments (using chemicals) must be kept at a maximum of 2.
  3. Sea lice is a health indicator. High parasite levels could negatively impact growth and cost/kg.
  4. Potentially, high lice levels could result in forced harvesting and less volumes.
  5. The parasites could also harm the stocks of wild salmon and sea trout.

Next I show the sea lice level on the county level. From Finnmark in North to Rogaland in the South. First, up is Finnmark, which rarely approach the maximum limit.


Also, in Troms, the number of sea lice in Troms rarely approach the maximum limit.


This is the current situation in Nordland.


In Nord Trøndelag, we have occasionally seen high sea lice levels in the past.


Sør Trøndelag is where some of the largest farming sites are located, for instance SalMar.


This is the current situation in Møre og Romsdal


Next I show the sea lice levels in Sogn og Fjordane.


And this is how the current situation is in Hordaland.


Finally, I show the sea lice levels in region Rogaland, the southernmost farming county in Norway.

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