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15 years of breeding work against ISA has produced results for SalmoBreed

During four generations, we have seen a 26% reduction in mortality

BERGEN: As of 23. September there are registered 9 outbreaks or suspected outbreaks of ISA in Norway in 2016. In only a few of these, the fish has originated in genetics from SalmoBreed. Manager Jan-Emil Johannessen is very satisfied:

This shows that it was a very good decision to keep the ISA as a part of our breeding work. 15 years of systematic breeding have produced results, we now have a unique opportunity to use genomic selection (GS) to build the best individuals.

Infectious salmon anemia, ISA, strikes salmon but also rainbow trout. Because it is classified as a class 2 disease in Norway, the authorities require eradication of fish groups where ISA is proven. The disease is transmitted between fish, via water; It is therefore essential to keep infection pressure as low as possible to avoid the spread of the disease.

Outbreaks every year

The Veterinary Institute collected statistics about ISA outbreaks. After big problems in the 90 ‘s, the number of outbreaks per year have been relatively low, yet there are annual occurrences and from 2013, there has been between 10 and 15 outbreaks per year. With 9 outbreaks so far the situation seems to remain at this level also in 2016.

Ilautbrudd 1984 2016 Sept

ISA-occurrences per year 1984-2016 (per September 23rd 2016) Source: The Veterinary Institute

Big genetic variation

SalmoBreed has weighted for robustness against ISA since 2001. There is a large genetic variation in resistance capacity amongst salmon families. Breeding is therefore a well-suited tool in the struggle against ISA.

-Throughout the period we have annually made infection attempts and selected breeding candidates from the sibling groups that coped the best, says Jan-Emil. During four generations, we have seen a 26% reduction in mortality

Keeping the infection pressure low

Even though fish with proven infection must be slaughtered out, it is important that the fish not only is resistant to disease, but also that an outbreak progresses as mildly as possible. Sick fish will excrete virus; it increases the infection pressure on facilities that share the water tanks. We therefore look at survival in outbreaks as an important criterion when we choose breeding fish.

Ila Familievariasjon

Genetic variation in resistance/survival against the ISA in SalmoBreed’s breeding program

Genomic selection

15 years of breeding has given a lot of knowledge. The knowledge of the salmon genotype, and the selection of individuals that are the most robust against ISA, helped SalmoBreed from 2015 to use genomic selection in the work with ISA.

-With genomic selection, we can select breeding fish at individual level, and the precision of breeding becomes even higher, says Salmobreed’s Genetics Director Borghild Hillestad. We see that GS produces good results for both PD and salmon lice and we are very pleased that we can now offer an efficient GS ISA on our product list.

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