Breakthrough in lice resistance from AquaGen

Egg-Update-logoNr. 3 / August 2015



Tre-lakselus-rotert-300x241AquaGen has discovered a QTL for lice susceptibility. By testing and selecting away brood fish with this lice-QTL, it will be possible to deliver eggs where the most lice receptive fish are removed from the population.

Amongst salmon farmers out on site it is a well-known fact that certain fish has got a much higher lice count than the cage average. These susceptible fish attract lice infection from the surrounding environment, and contribute to the build-up of a high infection pressure in the facility.

It is well-documented that the ability to resist salmon lice is hereditary. It will however take several generations of traditional breeding before achieving any kind of noticeable progress. Because of this, the AquaGen scientists have, for years, worked on identifying genetic markers that can provide quicker progress for the trait and thereby reducing the challenge of salmon lice in the industry.

After analyzing data from four large infection trials with salmon lice and close to 50 000 genetic markers from 4000 fish, the genetic marker (QTL), that is unique to salmon demonstrating high susceptibility for lice, was finally identified. Salmon that carry this marker has been found to have two to three times more lice than the population average.

In order to succeed with a non-medicinal control strategy it is of vital importance that the fish groups that are put in the sea have got a high and even natural resistance against lice infection.

Through identifying the genetic marker for lice susceptibility, AquaGen is able to test and eliminate parent fish with this marker. By doing this, the most lice susceptibility individuals will be removed before the farmed salmon is transferred to cages at sea.

The 2015/2016 stripping season is about to start, and all the preparations is close to finalization. The new lice-QTL can be a strong contributor for good lice control in the industry. Because of this, AquaGen will re-test the brood fish for the marker, to make sure our products will include a higher lice resistance for eggs produced in the 2015/2016 season.