Brage IMR
Not a member yet
12041 research outputs found
Sort by
Trajectory-based fish event classification through pre-training with diffusion models
Get PDFThis study contributes to advancing the field of automatic fish event recognition in natural underwater videos, addressing the current gap in studying fish interaction and competition, including predator-prey relationships and mating behaviors. We used the corkwing wrasse (Symphodus melops) as a model, a marine species of commercial importance that reproduces in sea-weed nests built and cared for by a single male. These nests attract a wide range of visitors and are the focal point for behavior such as spawning, chasing, and maintenance. We propose a deep learning methodology to analyze the movement trajectories of the nesting male and classify the associated events observed in their natural habitat. Our approach leverages unsupervised pre-training based on diffusion models, leading to improved feature learning. Additionally, we introduce a dataset comprising 16,937 trajectories across 12 event classes, making it the largest in terms of event class diversity. Our results demonstrate the superior performance of our method compared to several deep architectures. The code for the proposed method and the trajectories can be found at https://github.com/NoeCanovi/Fish_Behaviors_Generative_Models .publishedVersio
Seasonal habitat use and diel vertical migration in female spurdog in Nordic waters
Get PDFBackground Studying habitat use and vertical movement patterns of individual fish over continuous time and space is innately challenging and has therefore largely remained elusive for a wide range of species. Amongst sharks, this applies particularly to smaller-bodied and less wide-ranging species such as the spurdog (Squalus acanthias Linnaeus, 1758), which, despite its importance for fisheries, has received limited attention in biologging and biotelemetry studies, particularly in the North-East Atlantic. Methods To investigate seasonal variations in fine-scale niche use and vertical movement patterns in female spurdog, we used archival data from 19 pregnant individuals that were satellite-tagged for up to 365 days in Norwegian fjords. We estimated the realised niche space with kernel densities and performed continuous wavelet analyses to identify dominant periods in vertical movement. Triaxial acceleration data were used to identify burst events and infer activity patterns. Results Pregnant females frequently utilised shallow depths down to 300 m at temperatures between 8 and 14 °C. Oscillatory vertical moments revealed persistent diel vertical migration (DVM) patterns, with descents at dawn and ascents at dusk. This strict normal DVM behaviour dominated in winter and spring and was associated with higher levels of activity bursts, while in summer and autumn sharks predominantly selected warm waters above the thermocline with only sporadic dive and bursts events. Conclusions The prevalence of normal DVM behaviour in winter months linked with elevated likely foraging-related activity bursts suggests this movement behaviour to be foraging-driven. With lower number of fast starts exhibited in warm waters during the summer and autumn months, habitat use in this season might be rather driven by behavioural thermoregulation, yet other factors may also play a role. Individual and cohort-related variations indicate a complex interplay of movement behaviour and habitat use with the abiotic and biotic environment. Together with ongoing work investigating fine-scale horizontal movement as well as sex- and age-specific differences, this study provides vital information to direct the spatio-temporal distribution of a newly reopened fishery and contributes to an elevated understanding of the movement ecology of spurdog in the North-East Atlantic and beyond.publishedVersio
Panel-based Assessment of Ecosystem Condition of Norwegian Barents Sea Shelf Ecosystems - Appendices
Get PDFpublishedVersio
Survey report (Part 2) from the joint Norwegian/Russian Ecosystem Survey in the Barents Sea and the adjacent waters August-October 2023 — Marine environment, Mesozooplankton, Commercial Demersal Fish, Fish Biodiversity, Commercial Shellfish, Benthic Invertebrate Community, Marine Mammals and Seabirds
Get PDFThe aim of the joint Norwegian/Russian ecosystem survey in the Barents Sea and adjacent waters, August-October (BESS) is to monitor the status and changes of in the Barents Sea ecosystem. The survey has since 2004 been conducted annually in the autumn, as a collaboration between the IMR in Norway and the Polar Branch of VNIRO (PINRO) in Russia. The general survey plan, tasks, and sailings routes are usually agreed at the annual PINRO-IMR Meeting in March, but in 2023, due to external factors making physical meetings between Norwegian and Russian researchers difficult, they were agreed by correspondence. Survey coordinators in 2023 was Dmitry Prozorkevich (PINRO) and Geir Odd Johansen (IMR). No exchange of Russian and Norwegian experts between their respective vessels in 2023. The 21th BESS was carried out during the period from 10th August to 7th October by the Norwegian research vessels “Kronprins Haakon”, “G.O. Sars” and “Johan Hjort”, and the Russian vessels “Vilnyus”. The scientists and technicians taking part in the survey onboard the research vessels are listed in Table 1. As always, we would like to express our sincere gratitude to all the crew and scientific personnel onboard RVs “Vilnyus”, “G.O. Sars”, “Kronprins Haakon” and “Johan Hjort” and for their dedicated work, as well as all the people involved in planning and reporting of BESS 2023. This is a first part of the survey report summarising the observations and status assessments based on the survey data. The information obtained in BESS 2023 will be further used for the implementation of various international and national projects, assessment of fish and invertebrate stocks, environmental monitoring, etc.Survey report (Part 2) from the joint Norwegian/Russian Ecosystem Survey in the Barents Sea and the adjacent waters August-October 2023 — Marine environment, Mesozooplankton, Commercial Demersal Fish, Fish Biodiversity, Commercial Shellfish, Benthic Invertebrate Community, Marine Mammals and SeabirdspublishedVersio
Intercorrelations of Chlorinated Paraffins, Dechloranes, and Legacy Persistent Organic Pollutants in 10 Species of Marine Mammals from Norway, in Light of Dietary Niche
Get PDFShort-, medium-, and long-chain chlorinated paraffins (CPs) (SCCPs, MCCPs, and LCCPs) and dechloranes are chemicals of emerging concern; however, little is known of their bioaccumulative potential compared to legacy contaminants in marine mammals. Here, we analyzed SCCPs, MCCPs, LCCPs, 7 dechloranes, 4 emerging brominated flame retardants, and 64 legacy contaminants, including polychlorinated biphenyls (PCBs), in the blubber of 46 individual marine mammals, representing 10 species, from Norway. Dietary niche was modeled based on stable isotopes of nitrogen and carbon in the skin/muscle to assess the contaminant accumulation in relation to diet. SCCPs and dechlorane-602 were strongly positively correlated with legacy contaminants and highest in killer (Orcinus orca) and sperm (Physeter macrocephalus) whales (median SCCPs: 160 ng/g lw; 230 ng/g lw and median dechlorane-602: 3.8 ng/g lw; 2.0 ng/g lw, respectively). In contrast, MCCPs and LCCPs were only weakly correlated to recalcitrant legacy contaminants and were highest in common minke whales (Balaenoptera acutorostrata; median MCCPs: 480 ng/g lw and LCCPs: 240 ng/g lw). The total contaminant load in all species was dominated by PCBs and legacy chlorinated pesticides (63–98%), and MCCPs dominated the total CP load (42–68%, except 11% in the long-finned pilot whale Globicephala melas). Surprisingly, we found no relation between contaminant concentrations and dietary niche, suggesting that other large species differences may be masking effects of diet such as lifespan or biotransformation and elimination capacities. CP and dechlorane concentrations were higher than in other marine mammals from the (sub)Arctic, and they were present in a killer whale neonate, indicating bioaccumulative properties and a potential for maternal transfer in these predominantly unregulated chemicals.publishedVersio
Genetisk analyse av skreitoktets eggsurvey 2022
Get PDFVi har bestemt artssammensetning i eggprøver fra skreitoktets eggsurvey i 2022 med genetisk analyse. Formålet har vært å kvalitetssikre den mikroskopiske artsbestemmelsen som inngår i den faste skreitoktprotokollen. Vi har særlig vært interessert i forvekslingsfaren mellom torsk og hyse, ettersom disse ikke lar seg skille ved mikroskopi. Vi fant en lavere mengde hyseegg enn det som var ventet ut i fra fangster av gytende hyse og nær samtidige tokt i nær overlappende område. Noen få håvtrekk hadde også store mengder egg som ikke lot seg sikkert bestemme genetisk. Det klare flertall av håvtrekk var imidlertid genetisk bestemt med få usikre egg, og vi fant i hovedsak svært godt samsvar mellom artsbestemmelse gjort ved hjelp av henholdsvis mikroskop og genetikk.Genetisk analyse av skreitoktets eggsurvey 2022publishedVersio
Diversification of marine aquaculture in Norway under climate change
Get PDFRecently there has been increased interest in species diversification in aquaculture as a strategy to adapt to climate change. Since species diversification is a long-term strategy, climate change and future farming conditions must be considered. The aim of this study was to evaluate how changing temperatures under different IPCC climate scenarios may affect marine aquaculture species diversification in Norway. Since farm conditions vary between locations, this study focused on four geographic areas (South, West, North and Arctic) and three farms within each area. Using a climate model downscaling of three climate scenarios (Shared Socioeconomic Pathways; SSP1–2.6, SSP2–4.5, and SSP5–8.5), daily temperatures from the years 2020–2099 were evaluated at each farm location to identify challenging conditions for 34 species. A Challenging Conditions Index (CCI) was developed based on species thermal tolerances to compare the 34 potential aquaculture species. The results showed differences in the number of challenging days (hot and cold) between areas, and even within areas, highlighting the need to consider site-specific conditions. For warm-water species more commonly farmed in the Mediterranean (e.g. European seabass, gilthead seabream), the calibrated model projections at the investigated Norwegian farm sites suggest that cold temperatures would still be challenging. Differences in the number of challenging days between the climate scenarios become more apparent towards the mid and end of century, though all scenarios show interannual variation rather than a constant change in conditions over time. Hence, any species selected for diversification purposes will have to be able to tolerate a range of temperature conditions, and species with narrower tolerance ranges could be a risk. These findings underline the importance of considering the interannually varying conditions that species will be exposed to rather than focusing solely on long-term averages. Establishing a new large-scale commercial aquaculture species takes a considerable amount of time and resources. Therefore, to support interpretation of the results and further studies on diversification under climate change, this study also introduces Aquaculture Readiness Level (ARL®) as a consistent evaluation of the research and development status, progress towards commercialisation and climate action orientated production. As species will have to be able to tolerate a range of temperature conditions over different years, the level of knowledge, resources, and innovation will have to be continually enhanced to improve adaptive capacity.publishedVersio
Monitoring program for pharmaceuticals, illegal substances and contaminants in farmed fish - Annual report for 2023
Get PDFThis report summarizes the results of the monitoring of illegal substances, pharmaceuticals, and contaminants in Norwegian farmed fish in 2023. In 2023, 2680 analyses were conducted on samples of 1815 fish. Samples examined for illegal substances were collected at all stages of farming and are representative of farmed fish under production. The samples were analyzed for substances with anabolic effect or unauthorized substances. Residues of testosterone were detected in one sample of rainbow trout. A follow-up investigation conducted by the Norwegian Food Safety Authority (Mattilsynet) concluded that contamination of the samples during sample taking was the cause of the positive result. Samples tested for approved veterinary drugs and contaminants were collected at slaughterhouses and are representative of Norwegian farmed fish ready for human consumption. Residues of the authorized anti-sealice agents emamectin, cypermethrin, and deltamethrin were found at concentrations below the respective Maximum Residue Limits (MRLs) in fish meat. Residues of other authorized veterinary drugs, such as antibiotics, drugs against internal parasites, or sedatives, were not detected. The concentrations of environmental contaminants were found below the EU Maximum Levels (MLs), where those are established for fish.Monitoring program for pharmaceuticals, illegal substances and contaminants in farmed fish - Annual report for 2023publishedVersio
Risk assessment of quercetin dihydrate and rutin in food supplements – “Other substances”
Get PDFacceptedVersio
The Eurasian Arctic Ocean along the MOSAiC drift in 2019–2020: An interdisciplinary perspective on physical properties and processes
Get PDFThe Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC, 2019–2020), a year-long drift with the Arctic sea ice, has provided the scientific community with an unprecedented, multidisciplinary dataset from the Eurasian Arctic Ocean, covering high atmosphere to deep ocean across all seasons. However, the heterogeneity of data and the superposition of spatial and temporal variability, intrinsic to a drift campaign, complicate the interpretation of observations. In this study, we have compiled a quality-controlled physical hydrographic dataset with best spatio-temporal coverage and derived core parameters, including the mixed layer depth, heat fluxes over key layers, and friction velocity. We provide a comprehensive and accessible overview of the ocean conditions encountered along the MOSAiC drift, discuss their interdisciplinary implications, and compare common ocean climatologies to these new data. Our results indicate that, for the most part, ocean variability was dominated by regional rather than seasonal signals, carrying potentially strong implications for ocean biogeochemistry, ecology, sea ice, and even atmospheric conditions. Near-surface ocean properties were strongly influenced by the relative position of sampling, within or outside the river-water influenced Transpolar Drift, and seasonal warming and meltwater input. Ventilation down to the Atlantic Water layer in the Nansen Basin allowed for a stronger connectivity between subsurface heat and the sea ice and surface ocean via elevated upward heat fluxes. The Yermak Plateau and Fram Strait regions were characterized by heterogeneous water mass distributions, energetic ocean currents, and stronger lateral gradients in surface water properties in frontal regions. Together with the presented results and core parameters, we offer context for interdisciplinary research, fostering an improved understanding of the complex, coupled Arctic System.publishedVersio