Breeding & Genetics
Our Breeding program
Keeping animals in a farming environment ultimately puts other demands on the animal than living in the wild.
- Greater animal density resulting in higher disease pressure.
- Regular handling resulting in stress.
- A different feeding regime than in the wild.
Through strategic breeding, the animals that adapt best to these conditions can be selected as parents for subsequent generations. The population will, over generations, be stronger, more robust and have improved overall performance in farmed conditions.
Our aim is to provide our customers with the best product available; A fish with high ability to take up and use the nutrition it’s offered, a strong immune system, high resistance to diseases and a low stress level.
What we aim for and how we achieve it
Stofnfiskur´s breeding program is based on family selection that also utilizes genomics and quantitative trait loci (QTL) to increase disease resistances.
Selective breeding is a natural and effective way off increasing productivity and family selection is a widely used tool when breeding animals like fish. In general, we look for the strongest families.
Salmon are born with 10-20 thousand full siblings and within the sibling group there is a similarity in traits. This enables us to do trials on some of the offspring in each family and choose the siblings of the best performing offspring as our next generation of brood fish.
Within each family there are genetic variations, leading to some individuals being stronger than others on specific traits. Combining family selection with other genetic methods like genomic selection, we can select the best performing individuals from the best performing families. The result is a very effective breeding program and a customer tailored product.
Our breeding program enables us to select many different traits simultaneously giving us the ability to meet many different customer demands. Today we select for two categories of traits, Production traits and health and well-being traits.
The most important traits we are selecting for today are:
|Production||Health & Well-being|
|Faster Growth||Disease Resistance*|
|Late Maturation||Salmon Louse Resistance|
*IPN, PD and SRS
Growth rate is one of the most important traits to improve in aquaculture. Shorter production period will reduce production cost, risk of disease outbreaks and risk sea lice infestation.
Over the last decade, the potential for genetic improvement of growth has been well documented in the StofnFiskur strain.
Since our breeding program started 7 generations (28 years) ago the production time from egg to harvest has been reduced by 5.5 months.
Our geneticists estimate that the breeding program shortens the production time by 1.57% each year
Quantitative trait loci (QTL)
QTLs is part of the DNA genome linked to a gene that controls a trait in an individual.
Since 1990 a considerable focus has been on Marker Assisted Selection (MAS) in animal breeding. In the last ten years this has been implemented in salmon breeding where the QTL findings have mainly been based on low density DNA markers (microsatellites).
IPN resistance in salmon is one of the success stories of using this approach in animal breeding, where a single DNA marker (microsatellite) is linked to disease resistance.
This has been utilized in the StofnFiskur breeding program to select salmon with high resistance to IPN.
A challenge with QTL based on low number markers, is that only a limited proportion of the total genetic variance is captured by a single marker. An alternative approach is to trace all the QTLs. This can be done by dividing the entire genome up into chromosome segments, and then tracing all the chromosome segments. This method is referred to as Genomic Selection (GS) by Meuwissen et al. (2001).
Moving to high density of genetic markers where microsatellites have been replaced by Single Nucleotide Polymorphism (SNP), has enabled us to capture more QTL’s underlying the trait.
In fish breeding, disease resistance and carcass traits are difficult to select for. The phenotypic records are obtained from relatives and not from candidates for selection. In such situations, Genomic Selection will increase accuracy using sibling information. QTL’s linked to desired traits can be utilized within family variations to select superior animals within the best family.
In cooperation with AgSearch in New Zealand we have included Genomic selection in our breeding program. This enables us to select faster for increased resistance to diseases like PD and SRS along with parasites such as salmon louse. Genomic selection is also a strong tool when selecting for carcass traits such as flesh colour and fat content.
Charles Darwin was the first to describe how domestication, selection and evolution are linked, based on heritability of traits among plants and animals.
The same principles are applied in artificial selection or selective breeding where behavioural traits such as temperaments and stress are heritable.
Behavioural traits are difficult to measure in aquaculture and are often treated as “hitch-hikers” in breeding programs. However, given individuals with similar growth potential, less stressed individuals are likely to grow better. These individuals are likely to be selected as brood fish meaning that with every generation we improve on the stress resistance of our brood stock.
Many of our customers have pointed out that the StofnFiskur stock is highly tolerant to handling during both the fresh- and sea water phase. This is also our experience from handling the fish in our facilities. Fish with low stress levels lead to minimal losses due to regular farming activities and handling.