Local and systemic gene expression responses of Atlantic salmon (Salmo salar L.) to infection with the salmon louse (Lepeophtheirus salmonis)

<p>Abstract</p> <p>Background</p> <p>The salmon louse (SL) is an ectoparasitic caligid crustacean infecting salmonid fishes in the marine environment. SL represents one of the major challenges for farming of salmonids, and veterinary intervention is necessary to combat infection. This study addressed gene expression responses of Atlantic salmon infected with SL, which may account for its high susceptibility.</p> <p>Results</p> <p>The effects of SL infection on gene expression in Atlantic salmon were studied throughout the infection period from copepodids at 3 days post infection (dpi) to adult lice (33 dpi). Gene expression was analyzed at three developmental stages in damaged and intact skin, spleen, head kidney and liver, using real-time qPCR and a salmonid cDNA microarray (SFA2). Rapid detection of parasites was indicated by the up-regulation of immunoglobulins in the spleen and head kidney and IL-1 receptor type 1, CD4, beta-2-microglobulin, IL-12β, CD8α and arginase 1 in the intact skin of infected fish. Most immune responses decreased at 22 dpi, however, a second activation was observed at 33 dpi. The observed pattern of gene expression in damaged skin suggested the development of inflammation with signs of Th2-like responses. Involvement of T cells in responses to SL was witnessed with up-regulation of CD4, CD8α and programmed death ligand 1. Signs of hyporesponsive immune cells were seen. Cellular stress was prevalent in damaged skin as seen by highly significant up-regulation of heat shock proteins, other chaperones and mitochondrial proteins. Induction of the major components of extracellular matrix, TGF-β and IL-10 was observed only at the adult stage of SL. Taken together with up-regulation of matrix metalloproteinases (MMP), this classifies the wounds afflicted by SL as chronic. Overall, the gene expression changes suggest a combination of chronic stress, impaired healing and immunomodulation. Steady increase of MMP expression in all tissues except liver was a remarkable feature of SL infected fish.</p> <p>Conclusion</p> <p>SL infection in Atlantic salmon is associated with a rapid induction of mixed inflammatory responses, followed by a period of hyporesponsiveness and delayed healing of injuries. Persistent infection may lead to compromised host immunity and tissue self-destruction.</p

Diet analysis of Atlantic salmon (Salmo salar) post-smolts after the ecological regime shift in the Northeast Atlantic

Transition from freshwater to saltwater presents multiple challenges for anadromous Atlantic salmon, and survival during this critical life-stage is thought to influence adult population abundance. Despite this, the role of feeding, which influences growth and therefore survival, is poorly studied. Here, we analyzed the diet of 580 post-smolts captured in four Norwegian fjords in 2018 and 2019. Post-smolt diet mainly consisted of fish larvae (Teleostei), krill (Euphasiidae), planktonic amphipods, and insects. However, diet varied among fjords and years. For example, post-smolts in Altafjord in northern Norway displayed a higher frequency of fish larvae in their diet compared to post-smolts from fjords in western Norway, although this effect was less clear in 2019 than in 2018. Post-smolts consuming fish larvae and/or krill displayed substantially higher feeding ratios, and these fish were on average 0.52 cm longer. This observation underpins results from earlier studies suggesting that consumption of fish larvae is important for marine growth and ultimately survival. The dietary observations reported here may therefore have implications for spatial and temporal patterns in Atlantic salmon marine survival rates in this region. Furthermore, we did not detect any clear differences in diet between post-smolts analyzed here in comparison with post-smolts collected in the same region approximately 20 years earlier. As there has been a well-documented ecological regime shift in the Northeast Atlantic between the present and earlier studies, we conclude that it has not had a large impact on post-smolt feeding conditions within Norwegian fjords. Diet Fish larvae Coastal ecosystem Migration EstuarypublishedVersio

The Dashboard: an online system to help build an online presence and measure analytics for micro-businesses

Digital marketing plays an important role for businesses trying to attract new customers. For micro-businesses (0-9 workers) or self- run businesses it can be difficult to find the time to market yourself online. Non tech-savvy individuals can be unaware of where to start or how to set up a website. It can be time consuming, costly and difficult to understand the digital requirements. In this paper, we describe an online system - the dashboard, to help micro-businesses learn about building an online presence, using a range of available digital services, and providing analytical data on services that they are using. We discuss how analytic tools can help inform business owners of how useful online marketing tools are for their business and which services attract the most customers and revenue

Rural Enterprise as an Agent for Technology Development and Facilitation in the Digital Economy

This paper outlines recent developments in the Scaling the Rural Enterprise (SRE) research project – an interdisciplinary project that combines the expertise of social scientists, computer scientists and software developers, in order to inform the development and design of digital technologies in a rural context. The paper provides a brief overview of the research undertaken. It then highlights the outcomes from three stages of the work. Initially, it undertakes a review of associated literature and discusses issues of definition in relation to rural enterprises in the UK. Following this we present the insights from rural business advisers on the current state of use of digital technologies in these organisations. This then leads to work that analyses community- based enterprises as agents of economic change and gatekeepers to the introduction of digital technology solutions. The paper concludes by highlighting some implications for the design of digital tools and services

The potential for cleaner fish-driven evolution in the salmon louse Lepeophtheirus salmonis: Genetic or environmental control of pigmentation?

The parasitic salmon louse represents one of the biggest challenges to environmentally sustainable salmonid aquaculture across the globe. This species also displays a high evolutionary potential, as demonstrated by its rapid development of resistance to delousing chemicals. In response, farms now use a range of non-chemical delousing methods, including cleaner fish that eat lice from salmon. Anecdotal reports suggest that in regions where cleaner fish are extensively used on farms, lice have begun to appear less pigmented and therefore putatively less visible to cleaner fish. However, it remains an open question whether these observations reflect a plastic (environmental) or adaptive (genetic) response. To investigate this, we developed a pigment scoring system and conducted complimentary experiments which collectively demonstrate that, a) louse pigmentation is strongly influenced by environmental conditions, most likely light, and b) the presence of modest but significant differences in pigmentation between two strains of lice reared under identical conditions. Based on these data, we conclude that pigmentation in the salmon louse is strongly influenced by environmental conditions, yet there are also indications of underlying genetic control. Therefore, lice could display both plastic and adaptive responses to extensive cleaner fish usage where visual appearance is likely to influence survival of lice.publishedVersio

Genetic variation for upper thermal tolerance diminishes within and between populations with increasing acclimation temperature in Atlantic salmon

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.publishedVersio

Accountable artefacts: the case of the Carolan guitar

We explore how physical artefacts can be connected to digital records of where they have been, who they have encountered and what has happened to them, and how this can enhance their meaning and utility. We describe how a travelling technology probe in the form of an augmented acoustic guitar engaged users in a design conversation as it visited homes, studios, gigs, workshops and lessons, and how this revealed the diversity and utility of its digital record. We describe how this record was captured and flexibly mapped to the physical guitar and proxy artefacts. We contribute a conceptual framework for accountable artefacts that articulates how multiple and complex mappings between physical artefacts and their digital records may be created, appropriated, shared and interrogated to deliver accounts of provenance and use as well as methodological reflections on technology probes

Genetiske analyser av aure i Gloppenelva

I Gloppenelva ble det åpnet en laksetrapp i Eidsfossen i 1972, men trappen ble stengt i 2014 etter store skader under en flomhendelse, og det er ikke avklart om trappen skal restaureres. Inntil 1972 var Eidsfossen vandringshinder for anadrom fisk i Gloppenvassdraget. Det er ikke kjent om sjøaure vandret opp trappen og reproduserte oppstrøms i perioden 1971 til 2014, og det er ikke gjennomført kultivering med sjøaure oppstrøms Eidsfossen eller flyttet sjøaure forbi fossen. For å avklare om sjøaure har vandret opp og satt genetiske avtrykk i aurebestandene oppstrøms trappen i Eidsfossen ble det gjennomført genetiske analyser av aure på elvestrekningen mellom Eidsfossen og Trøselfossen som er neste vandringshinder oppstrøms, og i sideelva Ryssdalselva på denne strekningen.Genetiske analyser av aure i GloppenelvapublishedVersio

Rømt og vill fisk i Etneelva 2022 - Resultat frå den nasjonale forskingsplattforma i Etne

I 2022 vart fiskefella i Etneelva sett i drift 19. april og registreringa pågjekk til 12. november. Det var noko redusert fangseffektivitet i løpet av sesongen pga høg vassføring. I tilsaman 12 driftsdøgn (6% av driftstida) var fangsten i fella redusert pga mykje vatn. Tilsvarande reduksjon i fangsteffektivitet hadde vi også i 2021 (9%), 2020 (5%) og 2019 (5%). Fyrste villaks blei registrert i veke 17 og fyrste rømling i veke 24. I alt vart 4063 fiskar handtert på fella i 2022, mot 3746 i 2021, 5093 i 2020 og 2693 i 2019. Av dei registrerte fiskane var 2042 villaks,1916 sjøaure, 51 forskingsfisk, 1 pukkellaks og 53 rømte laks. I 2022 hadde 50% av villaksen vandra opp pr. veke 28, fire veker tidlegare enn rømlingane. Som tidlegare år dominerte storlaksen tidleg i oppvandringa medan terten dominerte i slutten av oppvandringsforløpet. For rømlingane registrert på fella varierte storleiken frå 0,85 kg til 9,2 kg, med ei overvekt av individ på 3,0 til 4,0 kg. Skjellkontrollen stadfesta oppdrettsbakgrunn til alle dei registrerte oppdrettslaksane. Av dei 53 registrerte rømlingane på fella, var 47% kjønnsmodne og 49% umodne. Gjennom uttaksfisket om hausten nedstraums fella i sone 1 og 2, vart det fanga 33 oppdrettslaksar. Av dei vart 3 (9%) klassifisert som modne, 25 (76%) vart klassifisert som umodne og 5 (15%) vart ikkje modningsbestemt. Frå sportsfisket blei det rapportert inn 17 oppdrettslaksar nedstraums fella, og ein regnbogeaure oppstraums. Av dei 17 rapporterte rømlingane nedstraums, vart seks verifisert ved skjellkontroll. For dei 11 andre vart det ikkje teke skjellprøve. Det vart heller ikkje teke skjellprøve frå regnbogeauren fanga oppstraums fella, men det vart lagt ved eit foto ved rapporteringa som stadfesta at dette var ein rømling. I dei resterande skjellprøvane frå sportsfisket nedstraums fella, blei det ikkje oppdaga fleire rømlingar. I skjellmaterialet av villaks teke i fiskefella er det heller ikkje funne fleire rømlingar. Basert på registreringane i fiskefella og rapporteringar av sportsfisket i Elveguiden, er andel rømt fisk i 2022 redusert frå 2,5 % til <0,1 %. Rundt 10 personar var i større eller mindre grad engasjert på fella og Havforskingsinstituttet sitt budsjett for drifta var ca 4 mill kroner med tillegg på 0,5 mill kroner frå OURO.Rømt og vill fisk i Etneelva 2022 - Resultat frå den nasjonale forskingsplattforma i EtnepublishedVersio

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. 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.publishedVersio