Blar i Publikasjoner fra CRIStin på forfatter "Johansen, Torild"
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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 ... -
Blålangegenetikk – Genetiske undersøkelser av blålange langs Eggakanten og i utvalgte fjorder
Helle, Kristin; Sanchez, Maria Quintela; Johansen, Torild (Rapport fra havforskningen;20-2018, Research report, 2018)Et intenst fiskepress på blålange på 1970- og 1980-tallet førte til alvorlig overbeskatning. Bestanden synes å være i så dårlig forfatning at den i 2006 ble satt på den norske Rødlisten. For å sikre gjenoppbygging av ... -
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 ... -
Distinct genetic clustering in the weakly differentiated polar cod, Boreogadus saida Lepechin, 1774 from East Siberian Sea to Svalbard
Sanchez, Maria Quintela; Bhat, Shripathi; Præbel, Kim; Gordeeva, Natalia; Seljestad, Gaute Wilhelmsen; Hanebrekke, Tanja Lexau; Mateos-Rivera, Alejandro; Vikebø, Frode Bendiksen; Zelenia, Daria; Cheng, Chi-Hing Christina; Johansen, Torild (Peer reviewed; Journal article, 2021)The cold-adapted polar cod Boreogadus saida, a key species in Arctic ecosystems, is vulnerable to global warming and ice retreat. In this study, 1257 individuals sampled in 17 locations within the latitudinal range of ... -
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 ... -
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 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 ... -
Genetic structure of Sufflogobius bibarbatus in the Benguela upwelling ecosystem using microsatellite markers
Gunawickrama, Kristogu Baduge Suneetha; Delaval, Aurelien Nicolas; Johansen, Torild; van der Plas, Anja; Salvanes, Anne Gro Vea (Peer reviewed; Journal article, 2020)The bearded goby Sufflogobius bibarbatus is an abundant endemic small fish species on the continental shelf of the northern Benguela. The goby habitat is characterised by generally low bottom oxygen concentrations that ... -
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. ... -
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, ... -
Linking dispersal connectivity to population structure and management boundaries for saithe in the Northeast Atlantic
Myksvoll, Mari Skuggedal; Devine, Jennifer Ann; Quintela, Maria; Geffen, Audrey J.; Nash, Richard David Marriott; Sandvik, Anne Dagrun; Besnier, Francois; Saha, Atal; Dahle, Geir; Jansson, Eeva; Nedreaas, Kjell Harald; Johansen, Torild (Peer reviewed; Journal article, 2021)Population connectivity is an increasingly important focal area for the understanding of how marine fish populations respond to anthropogenic pressures like climate change and fisheries. Our model species, the saithe ... -
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 ... -
Migration patterns of Greenland halibut in the North Atlantic revealed by a compiled mark-recapture dataset
Vihtakari, Mikko; Elvarsson, Bjarki Pór; Treble, Margaret; Nogueira, Adriana; Hedges, Kevin; Hussey, Nigel E.; Wheeland, Laura; Roy, Denis; Ofstad, Lise Helen; Hallfredsson, Elvar Halldor; Barkley, Amanda; Estevez-Barcia, Daniel; Nygaard, Rasmus; Healey, Brian; Steingrund, Petur; Johansen, Torild; Albert, Ole Thomas; Boje, Jesper (Peer reviewed; Journal article, 2022)Marine fisheries are often allocated to stocks that reflect pragmatic considerations and may not represent the species’ spatial population structure, increasing the risk of mismanagement and unsustainable harvesting. Here ... -
Morphology of Arctic cod (Boreogadus saida) assessed according to habitat preference and age in the Beaufort Sea
Malizia, Juliano; Launay, Marie; Bruvold, Ingrid Marie; Quintela, Maria; Johansen, Torild; Reist, James D.; Majewski, Andrew R.; Roy, Denis (Peer reviewed; Journal article, 2023)The Arctic cod (Boreogadus saida (Lepechin, 1774)) represents the most widespread and abundant fish in the Arctic and is a critical trophic link in its ecosystems. Like many species endemic to the region, it has lost ... -
Movement diversity and partial sympatry of coastal and Northeast Arctic cod ecotypes at high latitudes
Strøm, John Fredrik; Bøhn, Thomas; Skjæraasen, Jon Egil; Gjelland, Karl Øystein; Karlsen, Ørjan; Johansen, Torild; Hanebrekke, Tanja Lexau; Bjørn, Pål Arne; Olsen, Esben Moland (Peer reviewed; Journal article, 2023)Movement diversity within species represent an important but often neglected, component of biodiversity that affects ecological and genetic interactions, as well as the productivity of exploited systems. By combining ... -
Movement diversity and partial sympatry of coastal and Northeast Arctic cod ecotypes at high latitudes
Strøm, John Fredrik; Bøhn, Thomas; Skjæraasen, Jon Egil; Gjelland, Karl Øystein; Karlsen, Ørjan; Johansen, Torild; Hanebrekke, Tanja Lexau; Bjørn, Pål Arne; Olsen, Esben Moland (Peer reviewed; Journal article, 2023)Movement diversity within species represent an important but often neglected, component of biodiversity that affects ecological and genetic interactions, as well as the productivity of exploited systems. By combining ... -
New evidence for the establishment of coastal cod Gadus morhua in Svalbard fjords
Spotowitz, Lisa; Johansen, Torild; Hansen, Agneta; Berg, Erik; Stransky, Christoph; Fischer, Philipp (Peer reviewed; Journal article, 2022)The Arctic is experiencing increasing water temperatures, leading to a northward shift of Atlantic species into Arctic waters. Arctic marine ecosystems are therefore subject to substantial changes in species distributions ...