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Fish health

Bioassay sea lice

Sea lice occur naturally in the ocean. Conditions for unnatural favourable growth and spreading occur where sea lice are able to accumulate in large amounts, for example, at a fish farming site.

Lene-Catrin Ervik
Department manager for Fish health
Lene-Catrin Ervik

The aquaculture industry strives to keep the lice level as low as possible and below legal limits. This is achieved by maintaining good routines and preventative action. When delousing, it is crucial to choose the correct treatment and treatment method. Using the incorrect treatment or treatment method is expensive, time consuming and can lead to resistance.

To ensure correct use of the different medications, the sensitivity of the lice to the treatment must be monitored. Åkerblå monitors this in our internal laboratory using bioassays. This method is based on exposing pre-adult sea lice to different concentrations of the relevant medication.  Survival is documented and results are modelled to determine the median effective concentration (EC50). Different protocols are used for the different active ingredients in the medication.

Åkerblå performs bioassays on sea lice for the following medically active ingredients:

  • Deltametrin (Alphamax)
  • Cypemetrin (Betamax)
  • Azametifos (Salmosan)
  • Emamektin (Slice)
  • Hydrogenperokside (H2O2)
  • Other relevant products