Chromosomal aberrations and early mortality in a non-mammalian vertebrate: example from pressure-induced triploid Atlantic salmon.

In commercial aquaculture, the production of triploid fish is currently the most practical approach to prevent maturation and farm-to-wild introgression following escapes. However, triploids often exhibit poor welfare, and the underlying mechanisms remain unclear. Inheritance issues associated with sub-optimal hydrostatic pressure treatments used to induce triploidy, or the genetic background of parental fish, have been speculated to contribute.

A genetic method to infer ploidy and aberrant inheritance in triploid organisms.

Polyploidy occurs naturally across eukaryotic lineages and has been harnessed in the domestication of many crops and vertebrates. In aquaculture, triploidy can be induced as a biocontainment strategy, as it creates a reproductive barrier preventing farm-to-wild introgression, which is currently a major conservation issue for the industry. However, recent work suggests that triploidisation protocols may, on occasion, produce 'failed triploids' displaying diploidy, aneuploidy and aberrant inheritance.

Most of the escaped farmed salmon entering a river during a 5-year period were infected with one or more viruses.

Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014-2018, for five viral infections that are prevalent in global salmonid aquaculture. Over 90% of the escapees were infected with one or more viruses.

Pre-fertilization gamete thermal environment influences reproductive success, unmasking opposing sex-specific responses in Atlantic salmon ().

The environment gametes perform in just before fertilization is increasingly recognized to affect offspring fitness, yet the contributions of male and female gametes and their adaptive significance remain largely unexplored. Here, we investigated gametic thermal plasticity and its effects on hatching success and embryo performance in Atlantic salmon (). Eggs and sperm were incubated overnight at 2°C or 8°C, temperatures within the optimal thermal range of this species.

Lost in the loop - a qualitative study on patient experiences of care in standardized cancer patient pathways.

Background: The Norwegian health authorities introduced standardized cancer patient pathways (CPPs) in 2015, aiming to reduce practice variations across hospitals and regions, and improve the continuity, coordination and overall quality of the health care service provided to cancer patients. There has been few studies investigating this change, and that have looked into the organisational and economic benefits of standardized pathways, however the element of care and the patient perspective has been especially neglected. This study explored the care element in cancer patient pathways through an in-depth study of patient experiences.

Red and melanized focal changes in white skeletal muscle in Atlantic salmon (Salmo salar): Comparative analysis of farmed, wild and hybrid fish reared under identical conditions.

Selective breeding plays a vital role in the production of farmed Atlantic salmon and has shown success in many aspects. Still, challenges related to fish health and welfare continue to result in significant economic losses. One such challenge is red and melanized focal changes (RFC/MFC), which result from acute and chronic inflammation, respectively, in the skeletal muscle.

An emotional roller coaster - family members' experiences of being a caregiver throughout a cancer trajectory.

Purpose: To explore family members' experiences of caregiving throughout a cancer trajectory from diagnosis until around one year after chemotherapy and radiation treatment ended.

Method: We conducted a longitudinal qualitative study using in-depth interviews with 13 family members at one to three points of time: before, during, and after treatment. To analyse the interviews, we leaned on Braun and Clark procedure for thematic analysis.

Introgression of domesticated salmon changes life history and phenology of a wild salmon population.

The release of domesticated conspecifics into the natural environment, whether deliberate or accidental, has the potential to alter the genetic integrity and evolutionary trajectory of wild populations. This widespread challenge is of particular concern for wild Atlantic salmon. By investigating phenotypic differences between the offspring of domesticated, hybrid, and wild Atlantic salmon released into the natural environment, earlier studies have documented the short-term consequences of introgression from domesticated fish into wild salmon populations.

In Limbo: Seven Families' Experiences of Encounter with Cancer Care in Norway.

Introduction: Like many other countries, Norway has seen a shift from inpatient to outpatient cancer care, with pathways aimed at improving the integration and coordination of health services. This study explores the perspectives of seven patients and their family members in light of this change. We focus on one particular phase of the pathway: the first encounter.

Domestication-induced reduction in eye size revealed in multiple common garden experiments: The case of Atlantic salmon ( L.).

Domestication leads to changes in traits that are under directional selection in breeding programmes, though unintentional changes in nonproduction traits can also arise. In offspring of escaping fish and any hybrid progeny, such unintentionally altered traits may reduce fitness in the wild. Atlantic salmon breeding programmes were established in the early 1970s, resulting in genetic changes in multiple traits.

Disentangling the effects of sex, life history and genetic background in Atlantic salmon: growth, heart and liver under common garden conditions.

Livestock domestication has long been a part of agriculture, estimated to have first occurred approximately 10 000 years ago. Despite the plethora of traits studied, there is little understanding of the possible impacts domestication has had on internal organs, which are key determinants of survival. Moreover, the genetic basis of observed associated changes in artificial environments is still puzzling.

Autosomal Pseudogenes Explain Discordances Between Phenotypic Sex and DNA Marker for Sex Identification in Atlantic Salmon.

Despite the key role that sex-determination plays in evolutionary processes, it is still poorly understood in many species. In salmonids, which are among the best studied fishes, the master sex-determining gene sexually dimorphic on the Y-chromosome () has been identified. However, displays unexplained discordance to the phenotypic sex, with a variable frequency of phenotypic females being reported as genetic males.

Epistatic regulation of growth in Atlantic salmon revealed: a QTL study performed on the domesticated-wild interface.

Background: Quantitative traits are typically considered to be under additive genetic control. Although there are indications that non-additive factors have the potential to contribute to trait variation, experimental demonstration remains scarce. Here, we investigated the genetic basis of growth in Atlantic salmon by exploiting the high level of genetic diversity and trait expression among domesticated, hybrid and wild populations.

Domestication leads to increased predation susceptibility.

Domestication involves adapting animals to the human-controlled environment. Genetic changes occurring during the domestication process may manifest themselves in phenotypes that render domesticated animals maladaptive for life in the wild. Domesticated Atlantic salmon frequently interbreed with wild conspecifics, and their offspring display reduced survival in the wild.

Evolutionary drivers of kype size in Atlantic salmon (): domestication, age and genetics.

The diversity of reproduction and associated mating patterns in Atlantic salmon () has long captivated evolutionary biologists. exhibit strategies involving migration, bold mating behaviours and radical morphological and physiological change. One such radical change is the elongation and curvature of the lower jaw in sexually mature males into a hook-like appendage called the kype.

The influence of vgll3 genotypes on sea age at maturity is altered in farmed mowi strain Atlantic salmon.

Background: In Atlantic salmon in the wild, age at maturity is strongly influenced by the vgll3 locus. Under farming conditions, light, temperature and feeding regimes are known significantly advance or delay age at maturity. However, the potential influence of the vgll3 locus on the maturation of salmon reared under farming conditions has been rarely investigated, especially in females.

Cryptic introgression: evidence that selection and plasticity mask the full phenotypic potential of domesticated Atlantic salmon in the wild.

Domesticated Atlantic salmon grow much faster than wild salmon when reared together in fish tanks under farming conditions (size ratios typically 1:2-3). In contrast, domesticated salmon only display marginally higher growth than wild salmon when reared together in rivers (size ratios typically 1:1-1.2).

Judging a salmon by its spots: environmental variation is the primary determinant of spot patterns in Salmo salar.

Background: In fish, morphological colour changes occur from variations in pigment concentrations and in the morphology, density, and distribution of chromatophores in the skin. However, the underlying mechanisms remain unresolved in most species. Here, we describe the first investigation into the genetic and environmental basis of spot pattern development in one of the world's most studied fishes, the Atlantic salmon.

Rapid growth causes abnormal vaterite formation in farmed fish otoliths.

Sagittal otoliths are essential components of the sensory organs that enable all teleost fish to hear and maintain balance, and are primarily composed of calcium carbonate. A deformity, where aragonite (the normal crystal form) is replaced with vaterite, was first noted over 50 years ago but its underlying cause is unresolved. We evaluated the prevalence of vateritic otoliths from two captive rearing studies which suggested that fast growth, due to environmental rather than genetic control, led to vaterite development.

Plasticity in growth of farmed and wild Atlantic salmon: is the increased growth rate of farmed salmon caused by evolutionary adaptations to the commercial diet?

Background: Domestication of Atlantic salmon for commercial aquaculture has resulted in farmed salmon displaying substantially higher growth rates than wild salmon under farming conditions. In contrast, growth differences between farmed and wild salmon are much smaller when compared in the wild. The mechanisms underlying this contrast between environments remain largely unknown.

Does density influence relative growth performance of farm, wild and F1 hybrid Atlantic salmon in semi-natural and hatchery common garden conditions?

The conditions encountered by Atlantic salmon, Salmo salar L., in aquaculture are markedly different from the natural environment. Typically, farmed salmon experience much higher densities than wild individuals, and may therefore have adapted to living in high densities.

Salmonid fish: model organisms to study cardiovascular morphogenesis in conjoined twins?

Background: There is a gap in knowledge regarding the cardiovascular system in fish conjoined twins, and regarding the cardiovascular morphogenesis of conjoined twins in general. We examined the cardiovascular system in a pair of fully developed ventrally conjoined salmonid twins (45.5 g body weight), and the arrangement of the blood vessels during early development in ventrally conjoined yolk sac larvae salmonid twins (<0.

Thermal plasticity in farmed, wild and hybrid Atlantic salmon during early development: has domestication caused divergence in low temperature tolerance?

Background: In the past three decades, millions of domesticated Atlantic salmon Salmo salar L. have escaped from farms into the wild. Their offspring display reduced survival in the natural environment, which demonstrates that gene-flow is likely to have a negative effect on wild populations.