The state of sea trout in 1251 Norwegian watercourses was assessed based on a scoring system for human pressures, abundance data, and local knowledge.Over 16,000 km of rivers and lakes were available to sea trout in these watercourses, spanning from the temperate to Arctic regions.Sea trout were classified to be in a good or very good state in fewer than 25% of the watercourses and in a poor or very poor state in almost 40%. Twenty-nine watercourses had lost their sea trout populations. Salmon lice from aquaculture salmon farms had by far the largest adverse effect on sea trout among the human impact factors, both in the number of watercourses (83%) and river area affected (60%), and the total effect on sea trout abundance. Agriculture and hydropower production also had strong adverse impacts (35% and 19% of watercourses), but substantially lower than that caused by salmon lice. Culverts related to road crossings and other habitat alterations also had impacts on sea trout in many watercourses (27%). Exploitation of sea trout has been reduced in Norway in recent years, both in the marine and freshwater fisheries. Yet, the exploitation pressure was moderate or high in almost 14% of the watercourses where the state of sea trout was poor or very poor, suggesting a high potential for overexploitation in these.The state of sea trout was best in the northern sparsely populated areas. However, distribution of watercourses with sea trout in a poor or very poor state was more linked to aquaculture, agriculture, and hydropower production than human population density.The developed approach for large-scale mapping of state and pressures, which is vital for prioritizing management measures, may inspire other nations in their conservation effort for this important species.
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. Here, we quantified the frequency and type of chromosomal aberrations in Atlantic salmon subjected to a gradient of sub-optimal pressure treatments (Experiment 1) and from multiple mothers (Experiment 2). From these experiments, we genotyped a subsample of ~900 eyed eggs and all ~3,300 surviving parr across ~20 microsatellites. Chromosomal aberrations included aneuploidy and uniparental disomy, which are evidence of genetic nondisjunction. Although a low frequency of chromosomal aberrations were identified in eyed eggs from the diploid and triploid controls, our results demonstrated that sub-optimal pressure treatments resulted in lower triploidization rates, increased incidence of chromosomal aberrations, and higher egg mortality rates. We also observed maternal effects on triploidization success and incidence of chromosomal aberrations. In contrast to the results in eggs, chromosomal aberrations were rare among surviving parr, suggesting a purge of maladapted individuals during early development. This is the first study to document a link between chromosomal aberrations and early mortality in a non-mammalian vertebrate, and has implications for aquaculture breeding programs.
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. Overall prevalences were: 75.7% for piscine orthoreovirus (PRV-1), 43.6% for salmonid alphavirus (SAV), 31.2% for piscine myocarditis virus (PMCV), 1.2% for infectious pancreatic necrosis virus (IPNV) and 0.4% for salmon anaemia virus (ISAV). A significantly higher prevalence of PMCV infection was observed in immature compared to mature individuals. The prevalence of both SAV and PMCV infections was higher in fish determined by fatty acid profiling to be 'recent' as opposed to 'early' escapees that had been in the wild for a longer period of time. This is the first study to establish a time-series of viral infection status of escapees entering a river with a native salmon population. Our results demonstrate that farmed escapees represent a continuous source of infectious agents which could potentially be transmitted to wild fish populations.
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. The potentially negative consequences for conservation and animal welfare motivate the need for methods to evaluate the success of ploidy-manipulation protocols early in the production process. We developed a semi-automated version of the MAC-PR (microsatellite DNA allele counting - peak ratios) method to resolve the allelic configuration of large numbers of individuals across a panel of microsatellite markers that can be used to infer ploidy, pedigree and inheritance aberrations. We demonstrate an application of the approach using material from a series of Atlantic salmon (Salmo salar) breeding experiments where ploidy was manipulated using a hydrostatic pressure treatment. We validated the approach to infer ploidy against blood smears, finding a > 99% agreement between these methods, and demonstrate its potential utility to infer ploidy as early as the embryonic stage. Furthermore, we present tools to assign diploid and triploid progeny to families and to detect aberrant inheritance, which may be useful for breeding programmes that utilise ploidy manipulation techniques. The approach adds to the ploidy verification toolbox. The increased precision in detecting ploidy and inheritance aberrations will facilitate the ability of triploidisation programmes to prevent farm-to-wild introgression.
Each year thousands of farmed Atlantic salmon escape from seawater net pens, and introgression has been documented in a range of wild populations. Due to greater experience in the wild, escapees that have been on the run for a longer period, and successfully transitioned to a wild diet (classified: "early escapees"), could potentially have a higher spawning success and contribute more to introgression than those that have been on the run for a shorter period and/or have not transitioned to a wild diet (classified: "recent escapees"). This is the first study to examine how the escape history of farmed Atlantic salmon captured in multiple rivers and coastal fisheries, varies in time and space. During 2011-2021, adult farmed escaped salmon were captured in four rivers and at six coastal sites in Norway. The level of linoleic acid, a terrestrial fatty acid high in commercial salmon feeds but low in the natural diet of wild salmon, was used to classify the farmed salmon as early or recent escapees. We observed temporal declines in the relative proportions of escaped vs. wild salmon in the catches, and the relative proportion of early vs. recent escapees in the most southern river (driven by samples from 2011 to 2015). Overall, 14% of the escaped salmon caught in the period were classified as early escapees. The relative proportion of early escapees was lower in the two southernmost rivers (21.2% and 6.30%), as compared to the coastal fisheries (40.9%) and the northernmost river (77.6%). Both aquaculture-management regulations and production strategies have likely influenced these observations.
Managers and stakeholders increasingly ask whether predation is a driving force behind the poor status of many species, and whether predator control is likely to be a successful management action to intervene. We review existing literature on Atlantic salmon Salmo salar predation and predator control, as well as general ecological theory on the role of predation in the life cycle of this iconic fish. Many bird, mammal, and fish predators target salmon at different life stages. In healthy salmon populations, predation is likely compensated for by reduced intraspecific competition during the freshwater stage. There is little evidence that predation alone has been an underlying mechanism for driving salmon populations below conservation limits. However, depending on the predator's response to salmon abundance, predation may keep decimated populations from recovering, even when the actual causes of decline have been removed. Under such a scenario, predation control may contribute to recovery, but there are no strong examples that clearly demonstrate the efficacy of managing predators to recover threatened salmon populations, challenging further applications.
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. Importantly, RFC/MFC has not been observed in wild Atlantic salmon, suggesting that both external and genetic factors may contribute to the development of inflammation. To investigate the underlying cause of RFC/MFC, we conducted a study involving 1854 Atlantic salmon of farmed, wild and hybrid origin. All fish were reared under identical conditions to minimize the influence of external factors. Throughout the production cycle, the fish was monitored for growth parameters and examined for RFC/MFC using macroscopic and histological analysis. We found no association between the experimental groups and the presence of RFC/MFC. Histological investigations revealed melano-macrophages in the soft tissue in freshwater smolt, although no macroscopic discoloration was observed. MFC showed granulomas in various stages, suggesting a complex progression of the condition. In summary, we conclude that RFC/MFC is primarily caused by external factors found in the rearing facilities of farmed Atlantic salmon.
Whilst aquaculture continues its global expansion, containment of fish in sea cages remains a persistent environmental challenge. Within Atlantic salmon Salmo salar farming, widespread escapes over several decades have left a legacy of ecological and genetic impacts on wild populations. Quantifying the characteristics of escapees, and how they vary in time and space, is important to understand how environmental impacts will vary and how mitigation strategies need to be tuned. Using a fish trap located in the River Etne on the west coast of Norway, we created an ecological and genetic profile for 616 escapees entering the river. The most important findings of the present study were (1) the annual number of escapees entering the trap declined in the period 2014-2018; (2) more than half of the escapees entering the river were mature; (3) the vast majority of escapees entering the river were categorised as recent escapees; (4) nearly all (96%) of the early escapees were mature upon entry to the river, while just over half (55%) of the recent escapees were mature; and (5) the escapees originated from multiple sources every year. We conclude that without the fish trap, this population would have been at risk of exposure to further spawning and introgression of domesticated salmon. Furthermore, the current findings of maturation status and escape history highlight the fact that mitigation efforts to reduce escape of smolts, post-smolts and larger fish all need continued attention from the management authorities and aquaculture industry.
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 (Salmo salar). Eggs and sperm were incubated overnight at 2°C or 8°C, temperatures within the optimal thermal range of this species. Crosses between warm- and cold-incubated gametes were compared using a full-factorial design, with half of each clutch reared in cold temperatures and the other in warm temperatures. This allowed disentangling single-sex interaction effects when pre-fertilization temperature of gametes mismatched embryonic conditions. Pre-fertilization temperature influenced hatch timing and synchrony, and matching sperm and embryo temperatures resulted in earlier hatching. Warm incubation benefited eggs but harmed sperm, reducing the hatching success and, overall, gametic thermal plasticity did not enhance offspring fitness, indicating vulnerability to thermal changes. We highlight the sensitivity of male gametes to higher temperatures, and that gamete acclimation may not effectively buffer against deleterious effects of thermal fluctuations. From an applied angle, we propose the differential storage of male and female gametes as a tool to enhance sustainability within the hatcheries.
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. Methods The patients were enrolled approximately three years after the introduction of standardized CPPs in Norway. Through a qualitative design with in-depth interviews, a total of 21 interviews were conducted with seven patients between 2018 and 2020. The first interview took place after the diagnosis was established and before treatment, the second interview during treatment, and the final interview approximately one year after the completion of active treatment. The empirical catchment area was eastern Norway. Data were analysed using a theoretical thematic analysis. Results This study sheds light on the complex challenges patients’ faces, while navigating CPPs, including the need for better transition support, improved coordination and continuity in care, and a more holistic approach that encompasses emotional well-being and family support. Three overarching themes were identified: [1] Navigating CPPs: patient care and transition challenges, [2] Fragmented cancer care: challenges in coordination and continuity [3] Unmet needs and overlooked opportunities in CPPs. Conclusions Patients experience that cancer patient pathways offer good medical treatment, but that the care element deserves more attention. Current CPPs are trapped in a logic of choice, preventing room for the element of care to receive the attention it requires for the patient to truly experience holistic person-centred care and continuous, well-coordinated services. Based in our study we argue there is a need to look into the missed opportunities for using the CPPs as points of departure for more holistic collaborative models for cancer care.
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. Result The analysis revealed three themes in family members' experiences of being a caregiver to a cancer patient throughout a cancer trajectory. These were: (1) From the time of diagnosis-overwhelming and uncertain; (2) During and after treatment-invisible and not involved; (3) Throughout the cancer trajectory-an emotional roller coaster. Conclusion The results indicated that the family members felt invisible and not involved and they experienced being a caregiver throughout the cancer trajectory as an emotional roller coaster. Our empirical findings thus indicate that in cancer care, family perspectives are yet to be implemented in daily practice. This is in contrast to explicit goals in current health policies underlining support and involvement of family members as a core aspect in cancer care.
Abstract Gene flow between wild and domestic populations has been repeatedly demonstrated across a diverse range of taxa. Ultimately, the genetic impacts of gene flow from domestic into wild populations depend both on the degree of domestication and the original source of the domesticated population. Atlantic salmon, Salmo salar, used in North American aquaculture are ostensibly of North American origin. However, evidence of European introgression into North American aquaculture salmon has accumulated in recent decades, even though the use of diploid European salmon has never been approved in Canada. The full extent of such introgression as well as the potential impacts on wild salmon in the Northwest Atlantic remains uncertain. Here, we extend previous work comparing North American and European wild salmon (n = 5799) using a 220 K SNP array to quantify levels of recent European introgression into samples of domestic salmon, aquaculture escapees, and wild salmon collected throughout Atlantic Canada. Analysis of North American farmed salmon (n = 403) and escapees (n = 289) displayed significantly elevated levels of European ancestry by comparison with wild individuals (p < 0.001). Of North American farmed salmon sampled between 2011 and 2018, ~17% had more than 10% European ancestry and several individuals exceeded 40% European ancestry. Samples of escaped farmed salmon similarly displayed elevated levels of European ancestry, with two individuals classified as 100% European. Analysis of juvenile salmon collected in rivers proximate to aquaculture locations also revealed evidence of elevated European ancestry and larger admixture tract in comparison to individuals collected at distance from aquaculture. Overall, our results demonstrate that even though diploid European salmon have never been approved for use in Canada, individuals of full and partial European ancestry have been in use over the last decade, and that some of these individuals have escaped and hybridized in the wild.
Marine aquaculture of Atlantic salmon (Salmo salar) is a relatively new industry where breeding programs have led to rapid genetic change in the captive populations that were built up alongside conspecific wild individuals. Throughout its 50-years history, marine aquaculture of Atlantic salmon has been associated with escapes, and studies have shown that escapees may enter rivers, spawn successfully, and this may lead to farmed-to-wild genetic introgression and maladaptation in wild populations. Yet, an open question is what factors can best explain the variability in the proportion of farmed escapees in wild populations, and when present, which additional factors lead to introgression. Here, we combine two large-scale data sets from monitoring escaped farmed salmon and introgression in Norwegian rivers between 2006 and 2018 to model how anthropogenic, environmental, and population factors influence proportion of escapees and level of introgression. We found that increasing farming intensity and river discharge increase the expected proportions of escaped farmed salmon in rivers, whereas a larger wild salmon population size reduces the expected proportion of escapees despite increasing the expected absolute numbers of escaped farmed salmon. On a large scale, introgression is primarily a function of proportions of escaped farmed salmon, and only to a minor extent a function of local environmental factors or salmon population characteristics. This suggests that as long as salmon aquaculture is based on technologies where non-sterile fish can escape, all anadromous wild Atlantic salmon populations are at risk. Large marine protected areas without salmon aquaculture may slow down the rate of intrusion and introgression by increasing the distance between intensive aquaculture and wild populations.
Abstract 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. However, few studies have investigated the joined product of introgression and natural selection after several generations. Here, we investigated the phenotypic response of an Atlantic salmon population that has been subjected to an average of 24% genetic admixture by domesticated conspecifics escaping from fish farms over three decades (approximately 6–7 generations). Individual levels of admixture were positively correlated with increased size at the smolt and adult stages for both sexes, a decrease in the age of male smolts, and a decrease in the age at maturity for males. These life history changes are presumably the consequence of the well‐documented directional selection for increased growth in domesticated salmon and are likely maladaptive. However, the most novel result of this study is that admixture was positively linked with delayed date of return to the river, with highly admixed fish arriving up to 26 days later than nonadmixed fish. Potentially, this phenological change provides admixed individuals with a survival advantage in the later phase of the life cycle as it reduces their period of exposure to selection through rod and line angling. We, therefore, conclude that while gene flow from domesticated conspecifics changes life history and phenological traits of wild Atlantic salmon populations, most of which are likely to be maladaptive, when pressured by additional anthropogenic challenges, some changes may confer a fitness advantage for a short part of the life cycle.
The escape of Atlantic salmon Salmo salar from aquaculture has been identified as a significant threat to the persistence and stability of wild salmon populations. Yet the magnitude of phenotypic impacts due to hybridization remains largely unresolved. We evaluated the phenotypic consequences of hybridization using geometric morphometrics both under natural conditions in the wild and in the laboratory using common garden experiments. Juvenile Atlantic salmon field-collected in 2015 and 2016 from 18 southern Newfoundland rivers were classified as pure wild, pure farm, or F 1 hybrids using genetic assignment. Overall size and shape differences between wild and farm, and wild and F 1 hybrid individuals were small, largely size related, and present between pure farm and other crosses. Laboratory-reared pure wild, pure farm, and F 1 hybrid salmon were grown in tank and semi-natural conditions. Wild fish were significantly larger than both farm and hybrid salmon at first feeding; these size differences remained at 80 d post first feeding under semi-natural conditions, but all crosses were the same size in tank conditions, and there were no differences between pure farm and hybrid individuals under either condition. Significant shape differences were present among all pairwise comparisons under tank conditions, and in semi-natural conditions, pure wild individuals differed significantly from pure farm and hybrid individuals. Our results suggest phenotypic differences observed under laboratory conditions between wild and farm×wild hybrid individuals may not be appreciable in the wild, and that significant genetic changes may occur in wild populations experiencing hybridization in the absence of obvious large phenotypic changes.
Populations may counteract lasting temperature changes or recurrent extremes through plasticity or adaptation. However, it remains underexplored how outbreeding, either naturally, unintentionally, or facilitated, may modify a local response potential and whether genotype-by-environment interactions or between-trait correlations can restrict this potential. We quantified population differences and outbreeding effects, within-population genetic variation, and plasticity of these, for thermal performance proxy traits using 32 pedigreed wild, domesticated, and wild-domesticated Atlantic salmon families reared under common-garden conditions. Following exposure to ambient cold (11.6 °C) or ~4° and ~8° warmer summer temperatures, populations differed notably for body length and critical thermal maximum (CTmax) and for thermal plasticity of length, condition, and CTmax, but not for haematocrit. Line-cross analysis suggested mostly additive and some dominant outbreeding effects on means and solely additive outbreeding effects on plasticity. Heritability was detected for all traits. However, with increasing acclimation temperature, differences in CTmax between populations and CTmax heritability diminished, and CTmax breeding values re-ranked. Furthermore, CTmax and body size were negatively correlated at the genetic and phenotypic levels, and there was indirect evidence for a positive correlation between growth potential and thermal performance breadth for growth. Thus, population differences (including those between wild and domesticated populations) in thermal performance and plasticity may present a genetic resource in addition to the within-population genetic variance to facilitate, or impede, thermal adaptation. However, unfavourable genotype-by-environment interactions and negative between-trait correlations may generally hamper joint evolution in response to an increase in average temperature and temporary extremes.
In 2015, 28 cancer pathways were introduced in the Norwegian public health care system. The rationale behind this change was to improve the integration of health care services in cancer care. The patients is for the patients and their family and caregivers shall experience a well-organized cancer care, a holistic treatment and predictable progression. The research literature shows that the term integrated care is not commonly used in cancer care. When used, integration and related terms are linked to coordination within or between hospital cancer teams and other specialist providers, not to highlight coordination and collaboration across administrative levels of health care systems. We wanted to expand the study of cancer care beyond evaluations of the hospital and specialist setting, and to address the gap in research about how the cancer patient and their family experience cancer care. The main aim of the overall PhD project is to develop a better understanding of the situation of cancer families in contact with the health care system. Method
In order to explore the main regulatory genes and pathways of growth traits in black porgy, Illumina high-throughput sequencing technology was used to perform transcriptome sequencing of mixed samples of brain, liver and muscle tissues of 4-month-old black porgy individuals with different growth rates, followed by bioinformatics analyses. Using GO (Gene Ontology) function enrichment analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) Pathway analysis, relevant regulatory pathways involved in the process of muscle growth and material metabolism of black porgy were found. In order to compare differentially expressed genes of fast-growing and slow-growing groups of black porgy, a total of 3104 DEGs were screened, of which 1129 were up-regulated genes and 1975 were down-regulated genes, including myosin heavy chain (MYH4), IGF-1, IGF-2, myosin light chain 3-like (Myl3), myosin-6-like (MYH6), myoglobin (Mb), growth hormone receptor type 1 (GHR1), and other key genes involved in the regulation of muscle growth. Through GO and KEGG enrichment analysis, we found 25 significantly enriched GO entries and 39 KEGG pathways related to growth, such as metabolic pathways, thyroid signalling pathways and PPAR signalling pathways. These differential genes and signalling pathways may play a key role in regulating growth of black porgy and provide a theoretical basis for further exploration of the key molecular mechanisms regulating growth and development of black porgy, ultimately contributing to the development of unique breeding strains of this species.
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. Our interviews were set in the period from referral until the start of treatment. Methods: Nineteen individual in-depth interviews were conducted in seven families. Seven patients with cancer and 12 family members were interviewed. Results: Three categories of experiences stood out in the empirical material: ‘Being in between different health professionals’, ‘Overwhelmed by written and oral informationʼ and ‘Lack of involvement’. Conclusion: This study provides insight into families’ experiences with cancer care from referral until the start of treatment. Our findings indicate that families often experience cancer care as fragmented and confusing. Although evaluations have shown that the introduction of cancer pathways seems to have a positive effect on waiting times and standardization of examinations across hospitals and regions, there is still potential for improvement in coordination between services, family involvement, and emotional and practical support. We argue that our findings highlight the tension between two ideals of professional care: standardization and patient-centredness. The study illustrates shortcomings in translating the ideal of patient-centredness into professional practice.