Brage IMR
Not a member yet
12041 research outputs found
Sort by
Cell death induced by Lepeophtheirus salmonis labial gland protein 3 in salmonid fish leukocytes: A mechanism for disabling host immune responses
Get PDFThe salmon louse (Lepeophtheirus salmonis) is an ectoparasite feeding on mucus, skin, and blood of salmonids. On parasitised fish erosions and, at later lice stages, ulcerations appear at the louse feeding site. In susceptible species like Atlantic salmon (Salmo salar) with a limited rejection of lice, only a mild inflammatory response with minor influx of immune cells is seen at these lesions, as the salmon louse secrete proteins that can dampen immune responses. In a previous study, Lepeophtheirus salmonis labial gland protein 3 (LsLGP3) was suggested to dampen cellular responses, and the present study aimed at increasing our understanding of its mode of action. LsLGP3 was found to be secreted on to the host skin, and both in vivo and in vitro experiments were performed to elucidate its function. Histological analysis of the louse attachment site revealed an epidermal and dermal influx of mainly macrophages and granulocytes after 5 days post infestation. The immune cell influx was deeper in the dermis throughout the louse infestation, and LsLGP3 may be involved in dampening this response. Enriched populations of Atlantic salmon B-cells, T-cells, granulocytes, and monocytes were exposed to recombinant LsLGP3 (recLGP3) in vitro, resulting in a significant decrease in cell viability compared to non-exposed controls. An apoptotic cell morphology with “beads-on-a-string” like protrusions was seen in all leukocyte cell fractions after recLGP3 exposure, but not in erythrocytes or keratocytes. A decreased viability was also detected in pink salmon leucocytes, which was not in leucocytes from non-salmonid species. These functional insights suggest that LsLGP3 specifically induces apoptosis of salmonid leukocytes and is likely a key protein secreted by the lice that disables the Atlantic salmon ability to mount an adequate immune response towards the salmon louse. In vivo LsLGP3 knock down studies indicated that the effect is localised primarily at the lice feeding site, without affecting immune cells that are not situated adjacent to the lice-inflicted lesion. The findings from this study could significantly aid in the development of new immune based anti-salmon louse prophylactic measures and treatments.publishedVersio
A global meta-analysis of gillnet bycatch of toothed whales: Mitigation measures and research gaps
Get PDFOdontocetes are globally distributed and are foundational to the structure and function of marine food webs, and hence bycatch impacts from gillnet fishing need to be considered in the context of their conservation and population viability. Currently, global gillnet bycatch numbers are unknown yet are estimated to be the greatest in Asia, East Africa, and the west coasts of North and South America. Here we provide the first global meta-analyses of small- and large-scale gillnet bycatch estimates of odontocetes during 1990–2020, compiling population size, estimated gillnet bycatch, and conservation status in support of geographical and species-specific risk estimates. We estimate that annual gillnet bycatch is ∼50,000 from 1990 to 2020, and, combined with overfishing, pollution, and noise, it has been shown to be a serious threat to these long-lived and slow-reproducing species with heavy offspring investment. The global gillnet bycatch of odontocetes is a difficult challenge to address and mitigate and requires improved species and regional-based management strategies including collaborations between fishers, fisheries managers, marine mammal experts, and marine spatial planners. This has been worked on for decades, yet more attention is needed for successful management of odontocete gillnet bycatch to ensure their sustainable future in the Anthropocene Ocean, in accordance with local subsistence dynamics and the relevant United Nations (UN) sustainable development goals.publishedVersio
ВЛИЯНИЕ КАМЧАТСКОГО КРАБА И КРАБА-СТРИГУНА ОПИЛИО НА СООБЩЕСТВА МЕГАБЕНТОСА БАРЕНЦЕВА МОРЯ
No full textpublishedVersio
Kartlegging av havnespy (Didemnum vexillum) i Haugesund og Karmøy kommune
Get PDFDen fremmede sjøpungen havnespy (Didemnum vexillum) ble første gang observert i Norge nær Stavanger i 2020. Høsten 2021 ble den også funnet i Haugesund og mange funn ble registrert av dykkere. Sommeren 2023 gjennomførte vi en undersøkelse der vi kartla forekomsten av havnespy i Haugesund og Karmøy kommune ved hjelp av en liten ROV. Det ble funnet mye havnespy sentralt i Haugesund by over ett område på 1,5 km2, men med spredte kolonier utenfor dette området. Vi fant ikke arten på travle kaier i Karmøy kommune på vestsiden av Karmsundet, noe som indikerer at spredning av larver om sommeren har vært den viktigste vektoren for spredning. Kaiene på Risøy er trolig det første stedet der arten ble etablert da det der ble funnet svært mye av arten og der den har kolonisert nesten alt tilgjengelig hardbunns-substrat.Kartlegging av havnespy (Didemnum vexillum) i Haugesund og Karmøy kommunepublishedVersio
Mareano leg 3 2023
Get PDFCruise Report from Mareano Leg 3, 2023. The objective of the cruise was MAREANO mapping of areas in the outer Oslofjord adn Skagerrak, but also to recover lost equipment owned by the Institute of Marine Research (video rig) and the Norwegian Defence Research Establishment (shellframe). The cruise was greatly affected by bad weather, necessitating alternative mapping areas outside the pre-planned areas of interest on several occasions due to this. Another aim of the cruise was to collect data with an Autonomous Underwater Vehicle (AUV) while conventional cruise activities were ongoing.Mareano leg 3 2023Mareano leg 3 2023publishedVersio
Program for overvåking av fôr til landdyr - Årsrapport for prøver analysert av Havforskningsinstituttet i 2023
Get PDFpublishedVersio
Prøvefiske med trollgarn og åleruser på grunt vatn om hausten - Strekninga Florø Ryfylke i perioden 2015-2023
Get PDFI denne rapporten samanfattar vi prøvefisket med trollgarn og åleruser etter torsk som har vorte gjennomført på faste stasjonar langs Vestlandskysten mellom Ryfylke og Florø sidan 2015. Vi legg særleg vekt på å beskriva korleis fisket har vorte gjennomført, samt å visa ein del av resultata frå prøvefisket på ein deskriptiv måte. Vi ser tydelege forskjellar mellom dei ulike områda, med generelt sett aukande fangstrater av torsk dess lenger nord ein kjem. Fangstane er likevel relativt låge, frå 0,4 – 1,7 torsk per garn i snitt mellom områda vi fiska på. I perioden vi har fiska (2015-2023) ser vi ingen tydelege endringar i fangst per reiskap frå år til år. Det er også svært vanskeleg å følga sterke eller svake årsklassar i materialet, sidan fangstratane uansett går raskt ned for torsk eldre enn 2-3 år.Prøvefiske med trollgarn og åleruser på grunt vatn om hausten - Strekninga Florø Ryfylke i perioden 2015-2023publishedVersio
Frozen storage procedures for salmon and plaice samples: Nutrient composition and implications for preservation
Get PDFWe hypothesized that removing water from fish muscle homogenate by freeze-drying might be a cost-effective way to stabilize nutrients and allow higher temperatures for long-term frozen storage prior to analytical measurements. To test our hypothesis, fish muscle fillets from lipid-rich farmed Atlantic salmon (n = 5) and lean wild-caught European plaice (n = 5) were homogenized and fresh-frozen at −20 and −80°C. A subset of these samples was freeze-dried prior to further frozen storage at the respective temperatures. Using validated methods, vitamins, amino acids, and fatty acids were measured after a short time of storage (starting point) and up to 1 year (endpoint), with intermediate analytical checkpoints of 1, 3, and 6 months. Trends in the degradation of certain nutrients during the different frozen storage conditions are discussed. In general, by freeze-drying fish homogenate samples prior to frozen storage at −20°C for up to 1 year, amino acids, vitamins, and fatty acids were stabilized in both salmon and plaice when compared to wet-frozen storage of the same samples, and storage at −80°C did not improve preservation of the freeze-dried samples. For wet-frozen samples, −80°C would be recommended for 1-year storage of fillet homogenate samples, even though several nutrients preserved well at −20°C.publishedVersio
Atlantic bluefin tuna tagged off Norway show extensive annual migrations, high site-fidelity and dynamic behaviour in the Atlantic Ocean and Mediterranean Sea
Get PDFAtlantic bluefin tuna (ABFT; Thunnus thynnus) is a highly migratory species. To investigate the migrations and vertical behaviours of ABFT migrating to Nordic waters, we deployed pop-up satellite archival transmitting tags on 25 ABFT off Norway (curved fork length: 228–292 cm). We obtained 16 full-year migrations, which differed between individuals, and physically recovered 13 tags, which provided 4699 days of archival depth and temperature data. ABFT occupied waters from the Arctic Circle to as far south as Cabo Verde, Africa, and occupied depths down to 1190 m and temperatures from 0.5 to 27.8°C. During their annual migrations, ABFT spent, on average, 68 days in Norwegian waters, 65 days in the Newfoundland Basin, 35 days around the Canary Islands and 33 days in the West European Basin. Most ABFT entered the Mediterranean Sea with a mean entry date of 13 May and visited known spawning grounds, staying, on average, 44 days. All ABFT with full-year deployments returned to Norwegian waters. ABFT displayed high site-fidelity and dynamic vertical diving behaviours that varied between hotspots and seasons. These spatiotemporal data provide important ecological knowledge for sustainable management and the conservation of the recently recovered eastern ABFT stock.publishedVersio
An analysis of air-sea gas exchange for the entire MOSAiC Arctic drift
Get PDFSea ice cover influences the generation of surface ocean turbulence in ways that sometimes enhance, but mostly inhibit air-water gas exchange. Inhibition happens as ice cover reduces wind fetch, enhancement occurs when haline convection or sea ice drift creates additional surface turbulence. We used the bulk turbulence relationships within the Wave Age Gas Transfer model to estimate air-sea gas transfer velocity (kWAGT), based on sea ice cover and turbulence conditions in the ice-ocean boundary layer, throughout a year-long (2019–2020) ice drift campaign in the central Arctic Ocean. During the drift, sea ice cover averaged >97%, with a minimum of 58%, and boundary layer shear played a dominant role in the turbulence budget. Modeled turbulent kinetic energy dissipation was compared against 167 in-situ profiles of ocean dissipation to evaluate model performance and explore related processes. The modeled dissipation and observed dissipation profiles, averaged over 0–4 m depth, agreed within 1% of each other, with a mean dissipation of 5.8 × 10−7 W kg−1. Examining individual dissipation estimates by surface conditions, however, revealed poorest agreement in leads, especially leads covered by thin ice, which the model cannot detect. Dissipation from the model was used to produce a time series of kWAGT, revealing an average velocity of 0.034 m d−1 or 1% of the global average for the open ocean. Comparison with a widely used wind speed parameterization for gas exchange showed that wind speed scaling would overestimate k during 92% of the drift by 3.5 times on average, demonstrating how fetch limitation can suppress gas exchange, even as open water increases. These results suggest that photic zone processes, under-ice blooms, and attendant cycling of CO2 and O2 as well as CH4 can remain isolated from the atmosphere for an entire annual cycle in the central Arctic.publishedVersio