Abstract Eddy‐resolving regional ocean model results in conjunction with synthetic float trajectories and observations provide new insights into the recirculation of Atlantic Water (AW) Fram Strait that significantly impacts redistribution oceanic heat between Nordic Seas Arctic Ocean. The simulations confirm existence a cyclonic gyre around Molloy Hole near 80°N, suggesting most AW within West Spitsbergen Current recirculates there, while colder westward mean flow south 79°N primarily...

The abundance of salmon lice in the Hardangerfjord is potentially large enough to be a threat wild fish stocks fjord. louse spends period 2–4 weeks its planktonic stages drifting current upper water masses fjord looking for suitable hosts on which settle. It important assess and distribution their phases order evaluate infection pressure they represent fish. system highly variable consists multitude components. This implicates similar variability dispersion. We find most efficient transport...

Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced individuals. Climate-induced changes in environmental conditions may alter those trade-offs resulting habitat use patterns. In this study, we investigated effect of sea temperature on acoustically tagged Atlantic cod (Gadus morhua) at Norwegian Skagerrak coast. Significant relationships between ocean were found. Under favourable thresholds (<16 °C), selected...

The Norwegian government has decided that the aquaculture industry shall grow, provided growth is environmentally sustainable. Sustainability scored based on mortality of wild salmonids caused by parasitic salmon lice. Salmon lice infestation pressure traditionally been monitored through catching sea trout and Arctic char using nets or traps trawling after Atlantic postsmolts. However, due to mainland coastline nearly 25 000 km, complementary methods may be used in order give complete...

Abstract High concentrations of microplastic particles are reported across the Arctic Ocean–yet no meaningful point sources, suspension timelines, or accumulation areas have been identified. Here we use Lagrangian particle advection simulations to model transport buoyant from northern European rivers high Arctic, and compare results flux sampled synthetic main entrance Ocean. We report widespread dispersal along Eurasian continental shelf, North Pole, back into Nordic Seas; with zones over...

Abstract The large‐scale population genetic structure of northern shrimp, Pandalus borealis , was investigated over the species’ range in North Atlantic, identifying multiple genetically distinct groups. Genetic divergence among sample localities varied 10 microsatellite loci (range: F ST = −0.0002 to 0.0475) with a highly significant average ( 0.0149; P &lt; 0.0001). In contrast, little or no differences were observed temporal replicates from same 0.0004; 0.33). Spatial patterns compared...

Annual mean total length ( L T ) of wild one‐sea‐winter 1SW Atlantic salmon Salmo salar the Norwegian River Imsa decreased from 63 to 54 cm with a corresponding decrease in condition factor K for cohorts migrating sea 1976 2010. The reduction is associated 40% decline individual mass, 2 1·2 kg. Hatchery fish reared parental same population exhibited similar changes 1981 onwards. correlated negatively near‐surface temperatures eastern Sea, thought be main feeding area present stock....

Abstract Norway has complicated dynamics in the coastal ocean and fjords. In this area is also largest salmon aquaculture industry world. The valuable for Norwegian economy worth more than 60 billion NOK. Thus, it important to know physical oceanography along coast, even variability on short temporal spatial scales (h/km), be able quantify environmental effects of industry. This motivation behind implementation a current model covering whole coast with relatively high grid size 800 m....

Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding local population structure and adaptation. Identifying underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification potential organisms to adapt persist response changing environment. Recent studies have documented cryptic, sympatric Atlantic cod (Gadus morhua) coastal areas. We analysed genetic origin 6,483...

Life on Earth has been characterized by recurring cycles of ecological stasis and disruption, relating biological eras to geological climatic transitions through the history our planet. Due increasing degree abruption caused human influences many advocate that we now have entered era Anthropocene, or "the age man." Considering ongoing mass extinction ecosystem reshuffling observed worldwide, a better understanding drivers will be requisite for identifying routes intervention mitigation....

The Pacific oyster Crassostrea gigas has recently expanded its range in Scandinavia. expansion is presumably a result of northwards larval drift. Massive settlements were recorded many areas along the Swedish west coast and southern Norway 2013 2014. After spawning season 2014, temperature surface water peaked at 24-26°C. this period, high sudden mortalities occurred hatchery wild populations south Norway. Surveys collected data showed that mainly during 3 wk September. All size classes...

Brown trout Salmo trutta (L.) is a facultative anadromous species, where portion of individuals in populations with access to the sea perform migrations use richer feeding resources. We investigated effect salmon lice Lepeophtheirus salmonis (Krøyer 1837) infestation on survival and behaviour wild post-smolts (average fork length = 180 mm) during their marine migration. Comparisons migratory were made between an artificially infested group (n 74) control 71) area low natural pressure....

Marine heatwaves (MHWs) are prolonged periods of extreme ocean warming that significantly impact marine ecosystems, fisheries, and aquaculture. In August 2024, northern Norway experienced one the most intense MHWs recorded since 2012, which coincided with a sharp rise in salmon lice infestations at aquaculture sites area. This study investigates atmospheric oceanic drivers this event, focusing on interaction local meteorological conditions large-scale climate variability. Using combination...

Abstract The Norwegian coast is populated by two cod populations: Northeast Arctic and Coastal cod. In this paper, we use a further division based on life history: oceanic cod, coastal fjord A numerical ocean model was implemented for the northern where all these populations have spawning areas. results were used to simulate connectivity retention of eggs from different subpopulations. reproduced observed variability mesoscale activity in Current. Eggs released at an area transported...

One mechanism by which marine organisms may respond to climate shifts is range shifts. The corkwing wrasse (Symphodus melops) a temperate fish species, inhabiting the coasts of Europe, that show strong indications current as well historical (ice-age) towards north. Nine neutral microsatellite DNA markers were screened study genetic signatures and spatial population structure over entire geographic thermal gradient species from Portugal Norway. A major break (F ST = 0.159 average among pairs)...

The Arctic Ocean is currently in transition towards a new, warmer state. Understanding the regional variability of oceanographic conditions important, since they have direct impact on local ecosystems. This work discusses implementation hydrodynamic model for Hornsund, southernmost fjord western Svalbard. Despite its location, Hornsund has stronger signature than other Svalbard fjords. was validated against available data, and seasonal mean circulation obtained from numerical simulations....

Abstract Mesoscale eddies are known to transport heat and biogeochemical properties from Arctic Ocean boundary currents basin interiors. Previous hydrographic surveys model results suggest that eddy formation may be common in the Atlantic Water (AW) inflow area north of Svalbard, but no quantitative survey has yet been done for region. Here vorticity water property signatures used identify track AW an eddy‐resolving sea ice‐ocean model. The current sheds along most length continental slope...

Abstract Salmon lice infestation is a major challenge for the aquaculture industry in Norway, threatening wild salmonid populations and causing welfare problems farmed salmon. Lice dispersion patterns are simulated by combining high-resolution hydrodynamic model Norwegian coast fjords with an individual-based salmon lice. We here present results from Altafjorden, sub-arctic fjord large stocks of salmonids, where inner part protected as National Fjord. The outer hosts several fish farms, our...

Abstract Albretsen, J., Aure, Sætre, R., and Danielssen, D. S. 2012. Climatic variability in the Skagerrak coastal waters of Norway. – ICES Journal Marine Science, 69: 758–763. The Institute Research Norway collects marine data from all national waters. Data are primarily collected vessels, but observation buoys, manual measurements, oceanographic gliders also used. most valuable long-term for elucidating decadal hydrographic along Norwegian coast time-series transect between Denmark,...