Atlantic salmon have been bred for use in aquaculture since the 1970’s. They have therefore become genetically different from wild fish. Meanwhile, the environment in which farmed salmon are produced is also different from the wild. In aquaculture fish are fed excessively and growth is much faster. In nature, most fish do not survive to adulthood and food can be scarce. Both the environment and the genetic background are important, and together they make up the phenotype of the fish.
Farmed salmon suffers many health issues. These problems may be caused by the artificial aquaculture environment, or perhaps they are an undesired biproduct of genetic trade-offs. Moreover, a major concern with aquaculture is that escaped farm fish interbreed with wild fish. This pollutes the gene pool and compromises the fitness of wild salmon.
The objective of this project is to study how genetics and environment affects the phenotype. We want to gain a better understanding of how functionally different domesticated and wild Atlantic salmon have become and decipher the relative importance of environment and genetics on several key functional traits. Traits measured include physiological capacities such as swimming abilities, metabolism, stress responses, and thermal and hypoxia tolerances. We will study immune functions in conjunction with parasite infestations. We will investigate morphological traits of the heart, otoliths, and vertebral column. Finally, we will study different life-stages to assess scaling effects and impacts on early life environment for success later in life. Combined, this will provide a nuanced quantifications of functional phenotypes of salmon with different genetics and environmental histories.
It is our hope that this project will benefit both fish welfare in aquaculture as well as conservation efforts of wild salmon. This project will start in July 2023 and run until June 2027. We are presently planning and preparing for the first runs of experiment.
This project for young research talents seeks to decipher the cause for variation in functional phenotypic traits of Atlantic salmon using experimental biology based on ecophysiological principles. Farmed salmon have been selectively bred for 50 years with a strong focus on growth performance which may have led to negative trade-offs with other key health related traits. In parallel, conservation concerns with wild populations exists owing to escaped farm fish interbreeding in nature, which may introduce inferior genotypes and thus hurt the natural fitness of wild salmon. However, owing to the tremendous capacity for phenotypic plasticity in fish, it remains unclear how different wild and domesticated salmon actually are from each other when considering environmental effects.
Here, different genotypes will be studied in different environmental contexts with a dedicated focus on resultant functional phenotypes as assessed through physiological, morphological and immunological measurements.
Wild caught salmon will be compared to hatchery reared counterparts of both domesticated and wild genetic origin. Moreover, clonal salmon lines using both heterozygous, homozygous and triploid variants will be used as a novel model to study phenotypic variation while genotypes remain constant. Different feeding regimes and incubation temperatures will be used to manipulate growth and development rates, while acclimation studies to thermal extremes will be used to compare climate resilience between wild and farmed salmon.
Physiological performance traits will be measured and include aerobic scopes, swimming capacities, hypoxia response, and thermal tolerance. Parasite tolerance and immunological responses to Lepeophtheirus salmonis in different genotypes will be assessed. Furthermore, functional cardiac morphology as influenced by genotype and development rates across life-stages will be analyzed along with the occurrences of vertebral and otolith deformities.