Browsing Brage IMR by Author "Westgaard, Jon-Ivar"
Now showing items 1-20 of 27
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Analysis of coastal cod (Gadus morhua L.) sampled on spawning sites reveals a genetic gradient throughout Norway's coastline
Dahle, Geir; Quintela, María; Johansen, Torild; Westgaard, Jon-Ivar; Besnier, Francois; Aglen, Asgeir; Jørstad, Knut Eirik; Glover, Kevin (Journal article; Peer reviewed, 2018)Atlantic cod (Gadus morhua L.) has formed the basis of many economically significant fisheries in the North Atlantic, and is one of the best studied marine fishes, but a legacy of overexploitation has depleted populations ... -
Benthic invertebrates in Svalbard fjords—when metabarcoding does not outperform traditional biodiversity assessment
Willassen, Endre; Westgaard, Jon-Ivar; Kongsrud, Jon Anders; Hanebrekke, Tanja Lexau; Buhl-Mortensen, Pål; Holte, Børge (Peer reviewed; Journal article, 2022)To protect and restore ecosystems and biodiversity is one of the 10 challenges identified by the United Nations’s Decade of the Ocean Science. In this study we used eDNA from sediments collected in two fjords of the Svalbard ... -
Boreal marine fauna from the Barents sea disperse to Arctic Northeast Greenland
Andrews, Adam; Christiansen, Jørgen Schou; Bhat, Shripathi; Lynghammar, Arve; Westgaard, Jon-Ivar; Pampoulie, Christophe; Præbel, Kim (Peer reviewed; Journal article, 2019)As a result of ocean warming, the species composition of the Arctic seas has begun to shift in a boreal direction. one ecosystem prone to fauna shifts is the Northeast Greenland shelf. the dispersal route taken by boreal ... -
Contaminants reach everywhere: Fish dietary samples should be surface decontaminated prior to molecular diet analysis
Rijal, Dilli Prasad; Hanebrekke, Tanja Lexau; Arneberg, Per; Johansen, Torild; Sint, Daniela; Traugott, Michael; Skern-Mauritzen, Mette; Westgaard, Jon-Ivar (Peer reviewed; Journal article, 2023)Knowledge of trophic interaction is necessary to understand the dynamics of ecosystems and develop ecosystem-based management. The key data to measure these interactions should come from large-scale diet analyses with good ... -
Extreme male-skewed sex ratios on spaning grounds for Atlantic cod Gadus morhua with typical coastal cod signatures of the Pan I (pantophysin) locus
Fevolden, Svein-Erik; Westgaard, Jon-Ivar; Pedersen, Torstein (Journal article; Peer reviewed, 2015-06-11)Large offshore and small inshore populations of Atlantic cod Gadus morhua L. display differences in migratory patterns and settling regimes, but little is known about possible differences in spawning behaviour. Cod presumably ... -
Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population.
Varne, Rebekka; Kunz, Kristina Lore; Johansen, Torild; Westgaard, Jon-Ivar; Uglem, Ingebrigt; Mork, Jarle (Journal article; Peer reviewed, 2015-11-18)This study investigated a potential genetic introgression from farmed to wild cod Gadus morhua L. in the Trondheimsfjord, Norway. During the first 2 yr of operation of a cod farm in the inner part of the fjord, 2 large ... -
Farming of Atlantic cod Gadus morhua in the vicinity of major spawning sites for Norwegian coastal cod populations - is it hazardous?
Fevolden, Svein-Erik; Westgaard, Jon-Ivar; Christiansen, Jørgen Schou (ICES CM documents;2009/Q:18, Working paper, 2009)Waters along and adjacent to the coast of northern Norway are unique in housing two major populations of Atlantic cod with very di erent life histories. The Northeast Arctic cod (NEAC) has its nursery and feeding grounds ... -
Genetic assignment as a tool to identify the origin for Atlantic cod (Gadus morhua) escapees in Norwegian fjords
Dahle, Geir; Jørstad, Knut Eirik; Johansen, Torild; Westgaard, Jon-Ivar; Knutsen, Halvor; Glover, Kevin A. (ICES CM documents;2009/Q:14, Working paper, 2009) -
Genetic differentiation between inshore and offshore populations of northern shrimp (Pandalus borealis)
Hansen, Agneta; Westgaard, Jon-Ivar; Søvik, Guldborg; Hanebrekke, Tanja; Nilssen, Einar Magnus; Jorde, Per Erik; Albretsen, Jon; Johansen, Torild (Dataset, 2021-07-18)This is the dataset used in Hansen et al study " Genetic differentiation between inshore and offshore populations of northern shrimp (Pandalus borealis)", published in ICES Journal of Marine Science. File Contents F1 ... -
Genetic differentiation between inshore and offshore populations of northern shrimp (Pandalus borealis)
Hansen, Agneta; Westgaard, Jon-Ivar; Søvik, Guldborg; Hanebrekke, Tanja Lexau; Nilssen, Einar Magnus; Jorde, Per Erik; Albretsen, Jon; Johansen, Torild (Peer reviewed; Journal article, 2021)Many marine organisms have a permanent presence both inshore and offshore and spawn in multiple areas, yet their status as separate populations or stocks remain unclear. This is the situation for the northern shrimp (Pandalus ... -
Genetic diversity within and among Atlantic cod (Gadus morhua) farmed in marine cages: a proof-of-concept study for the identification of escapees
Glover, Kevin A.; Dahle, Geir; Westgaard, Jon-Ivar; Johansen, Torild; Knutsen, Halvor; Jørstad, Knut Eirik (Journal article; Peer reviewed, 2010-03-23)This study presents a molecular genetic characterization of Atlantic cod reared in commercial marine farms. Samples consisted of approximately 47 fish collected from nine cages located on four farms throughout Norway. In ... -
Genetic management of mixed-stock fisheries "real-time": The case of the largest remaining cod fishery operating in the Atlantic in 2007-2017
Dahle, Geir; Johansen, Torild; Westgaard, Jon-Ivar; Aglen, Asgeir; Glover, Kevin (Journal article; Peer reviewed, 2018)Fish stocks represent fundamental units in fisheries management, and their identification, especially in mixed-fisheries, represents one of the primary challenges to sustainable harvest. Here, we describe the first “real-time” ... -
Genetic population structure in Norway lobster (Nephrops norvegicus): management regime under panmixia
Westgaard, Jon-Ivar; Johansen, Torild; Søvik, Guldborg (Peer reviewed; Journal article, 2023)Investigations of genetic stock structure sometimes reveal a mismatch between management units and biological units. In Scandinavian waters, Norway lobster (Nephrops norvegicus) is divided into two management units (the ... -
Genomic analysis reveals neutral and adaptive patterns that challenge the current management regime for East Atlantic cod Gadus morhua L
Johansen, Torild; Besnier, Francois; Sanchez, Maria Quintela; Jorde, Per Erik; Glover, Kevin; Westgaard, Jon-Ivar; Dahle, Geir; Lien, Sigbjørn; Kent, Matthew Peter (Peer reviewed; Journal article, 2020)Challenging long‐held perceptions of fish management units can help to protect vulnerable stocks. When a fishery consisting of multiple genetic stocks is managed as a single unit, overexploitation and depletion of minor ... -
Geographic extent of introgression in Sebastes mentella and its effect on genetic population structure
Saha, Atal; Johansen, Torild; Hedeholm, Rasmus; Nielsen, Einar Eg; Westgaard, Jon-Ivar; Hauser, Lorenz; Planque, Benjamin; Cadrin, Steven X.; Boje, Jesper (Peer reviewed; Journal article, 2017) -
Geographic variation in gene flow from a genetically distinct migratory ecotype drives population genetic structure of coastal Atlantic cod (Gadus morhua L.)
Seliussen, Bjørghild Breistein; Dahle, Geir; Johansen, Torild; Besnier, Francois; Quintela, Maria; Jorde, Per Erik; Knutsen, Halvor; Westgaard, Jon-Ivar; Nedreaas, Kjell Harald; Farestveit, Eva; Glover, Kevin Alan (Peer reviewed; Journal article, 2022)Identifying how physical and biotic factors shape genetic connectivity among populations in time and space is essential to our understanding of the evolutionary trajectory as well as the management of marine species. ... -
Geographic variation in gene-flow from a genetically distinct migratory ecotype drives population genetic structure of coastal Atlantic cod (Gadus morhua L.)
Seliussen, Bjørghild Breistein; Dahle, Geir; Johansen, Torild; Besnier, Francois; Sanchez, Maria Quintela; Jorde, Per Erik; Knutsen, Halvor; Westgaard, Jon-Ivar; Nedreaas, Kjell; Farestveit, Eva; Glover, Kevin (Dataset, 2022)This is the final dataset used in the Breistein et al. (in review) study “Geographic variation in gene-flow from a genetically distinct migratory ecotype drives population genetic structure of coastal Atlantic cod (Gadus ... -
Hierarchical genetic structure in an evolving species complex: Insights from genome wide ddRAD data in Sebastes mentella
Saha, Atal; Kent, Matthew Peter; Hauser, Lorenz; Drinan, Daniel P.; Nielsen, Einar E.; Westgaard, Jon-Ivar; Lien, Sigbjørn; Johansen, Torild (Peer reviewed; Journal article, 2021)The diverse biology and ecology of marine organisms may lead to complex patterns of intraspecific diversity for both neutral and adaptive genetic variation. Sebastes mentella displays a particular life-history as livebearers, ... -
Hierarchical genetic structure in an evolving species complex: insights from genome wide ddRAD data in Sebastes mentella
Saha, Atal; Kent, Matthew; Hauser, Lorenz; Drinan, Daniel P.; Nielsen, Einar E.; Westgaard, Jon-Ivar; Lien, Sigbjørn; Johansen, Torild (Dataset, 2021)This is the dataset used in Saha et al study "Hierarchical genetic structure in an evolving species complex: insights from genome wide ddRAD data in Sebastes mentella", published in Plos one. File Contents F1 This ... -
Maximizing sampling efficiency to detect differences in fish community composition using environmental DNA metabarcoding in subarctic fjords
Guri, Gledis; Westgaard, Jon-Ivar; Yoccoz, Nigel; Wangensteen, Owen S.; Præbel, Kim; Ray, Jessica Louise; Kelly, Ryan P.; Shelton, Andrew Olaf; Hanebrekke, Tanja Lexau; Johansen, Torild (Peer reviewed; Journal article, 2023)Environmental DNA (eDNA) has gained popularity as a tool for ecosystem biomonitoring and biodiversity assessment. Although much progress has been made regarding laboratory and fieldwork protocols, the issue of sampling ...