Browsing NTNU Open by Author "Davidsen, Jan Grimsrud"
Now showing items 1-20 of 46
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An effective method for the recapture of escaped farmed salmon
Chittenden, Cedar; Rikardsen, Audun H.; Skilbrei, Ove Tommy; Davidsen, Jan Grimsrud; Halttunen, Elina; Skardhamar, Jofrid; McKinley, R. Scott (Journal article; Peer reviewed, 2011)ABSTRACT: The search for effective strategies to prevent and mitigate accidental releases of aquaculture fishes is on-going. To test a new recapture strategy and evaluate the individual dispersal behaviour of escaped farmed ... -
The Biology and feeding Ecology of Arctic charr in the Kerguelen Islands
Eldøy, Sindre Håvarstein; Davidsen, Jan Grimsrud; Vignon, Matthias; Power, Michael (Peer reviewed; Journal article, 2020)Subsequent to their introduction in the 1950s, Arctic charr Salvelinus alpinus have been able to establish a self‐sustaining population that has adapted to the unique conditions of the sub‐Antarctic Kerguelen Islands. Here, ... -
Bridging the Gap between Fisheries Science and Society: Exploring Fisheries Science as a Social Activity
Bailey, Jennifer L.; Liu, Yajie; Davidsen, Jan Grimsrud (Journal article; Peer reviewed, 2016)Much has been written about the poor relations between fisheries scientists and lay people, but the experience of two field biologists suggests that good relations can exist and have a positive impact on the exchange of ... -
Changes in growth and migration patterns of sea trout before and after the introduction of Atlantic salmon farming
Eldøy, Sindre Håvarstein; Ryan, Diarmuid; Roche, William; Thorstad, Eva Bonsak; Næsje, Tor; Sjursen, Aslak Darre; Gargan, Paddy; Davidsen, Jan Grimsrud (Peer reviewed; Journal article, 2020)Marine growth has strong implications for reproductive potential and ultimate fitness of sea trout. Hence, the effects of anthropogenic factors on marine growth are important when evaluating population responses and ... -
A dated volcano-tectonic deformation event in Jan Mayen causing landlocking of Arctic charr
Larsen, Eiliv; Lyså, Astrid; Höskuldsson, Ármann; Davidsen, Jan Grimsrud; Nadeau, Marie-Josée; Power, Michael; Tassis, Georgios; Wastegård, Stefan (Peer reviewed; Journal article, 2021)We provide the first documentation of tectonic deformation resulting from a volcanic eruption on the island of Jan Mayen. Vertical displacement of about 14 m southwest of the stratovolcano Beerenberg is associated with an ... -
Demographic and genetic description of Greenland´s only indigenous Atlantic salmon (Salmo salar) population
Arnekleiv, Jo Vegar; Davidsen, Jan Grimsrud; Sheehan, T. F.; Lehnert, s.j.; Bradbury, I.R.; Rønning, Lars; Sjursen, Aslak Darre; Kjærstad, Gaute; Nilssen, Kjell J. (Journal article; Peer reviewed, 2018)In Greenland, Atlantic salmon are known to reproduce in only one river, the Kapisillit River. Little is known about the population characteristics or the relationship to other salmon populations across the species range, ... -
Early marine migration of European silver eel (Anguilla anguilla) in Northern Norway
Davidsen, Jan Grimsrud; Finstad, Bengt; Økland, Finn; Thorstad, Eva Bonsak; Mo, Tor Atle; Rikardsen, Audun H. (Journal article; Peer reviewed, 2011) -
Effects of sound exposure from a seismic airgun on heart rate, acceleration and depth use in free-swimming Atlantic cod and saithe
Davidsen, Jan Grimsrud; Dong, Hefeng; Linne, Markus; Andersson, Mathias H.; Piper, Adam; Prystay, Tanya S.; Hvam, Eivind B.; Thorstad, Eva Bonsak; Whoriskey, Frederick G.; Cooke, Steven J.; Sjursen, Aslak Darre; Rønning, Lars; Netland, Tim Cato; Hawkins, Anthony D. (Journal article; Peer reviewed, 2019)Recent vegetation changes in arctic-alpine tundra ecosystems may affect several ecosystem processes that regulate microbe and soil functions. Such changes can alter ecosystem carbon (C) cycling with positive feedback to ... -
Effekter av økt vannuttak om sommeren fra Rovatnet i Hemne kommune på laks, sjøørret, bunndyr og elvemusling
Sjursen, Aslak Darre; Kjærstad, Gaute; Daverdin, Marc; Davidsen, Jan Grimsrud (NTNU Vitenskapsmuseet naturhistorisk notat;, Research report, 2018)Effekter av økt vannuttak fra Søavassdraget i Hemne kommune – NTNU Vitenskapsmuseet naturhistorisk notat 2018-8: 1-20. I forbindelse med AquaGen sin planlegging av oppgradering av anlegget på Kyrksæterøra med et nytt ... -
Environmental influences on life history strategies in partially anadromous brown trout (Salmo trutta, Salmonidae)
Nevoux, Marie; Finstad, Bengt; Davidsen, Jan Grimsrud; Finlay, Ross; Josset, Quentin; Poole, Rusell; Höjesjö, Johan; Aarestrup, Kim; Persson, Lo; Tolvanen, Oula; Jonsson, Bror (Journal article; Peer reviewed, 2019)This paper reviews the life history of brown trout and factors influencing decisions to migrate. Decisions that maximize fitness appear dependent on size at age. In partly anadromous populations, individuals that attain ... -
Ferskvannsbiologiske undersøkelser i Auretjørnelva i Namsos kommune - Vurdering av effekter av vannuttak på fisk og bunndyr
Sjursen, Aslak Darre; Rønning, Lars; Kjærstad, Gaute; Davidsen, Jan Grimsrud (NTNU Vitenskapsmuseet naturhistorisk notat;, Research report, 2019) -
Ferskvannsbiologiske undersøkelser i Fuglevågvassdraget, Smøla kommune. Vurdering av effekter av økt vannuttak fra Storvatnet på fisk og bunndyr
Sjursen, Aslak Darre; Rønning, Lars; Kjærstad, Gaute; Davidsen, Jan Grimsrud (NTNU Vitenskapsmuseet naturhistorisk notat;, Research report, 2020)Sjursen, A.D., Kjærstad, G., Rønning, L. & Davidsen, J.G. 2020. Ferskvannsbiologiske undersøkelser i Fuglevågvassdraget, Smøla kommune. Vurdering av effekter av økt vannuttak fra Storvatnet på fisk og bunndyr – NTNU ... -
Ferskvannsbiologiske undersøkelser i Samsjøen, Holtsjøen, Samaelva og Søavassdraget, Sør-Trøndelag, i 2017
Davidsen, Jan Grimsrud; Sjursen, Aslak Darre; Davidsen, Anette Sophie Grimsrud; Kjærstad, Gaute; Rønning, Lars; Daverdin, Marc; Værnes, Einar; Hårsaker, Karstein; Arnekleiv, Jo Vegar (NTNU Vitenskapsmuseet naturhistorisk rapport;, Research report, 2018) -
Fiskebiologiske undersøkelser i Beiarelva 2017-19. Årsrapport for 2017
Sjursen, Aslak Darre; Hansen, Øyvind Kanstad; Rønning, Lars; Arnekleiv, Jo Vegar; Davidsen, Jan Grimsrud (NTNU Vitenskapsmuseet naturhistorisk rapport;, Research report, 2018) -
Fiskebiologiske undersøkelser i Beiarelva 2017-19. Årsrapport for 2018
Sjursen, Aslak Darre; Rønning, Lars; Arnekleiv, Jo Vegar; Davidsen, Jan Grimsrud (NTNU Vitenskapsmuseet naturhistorisk rapport;, Research report, 2019)Med bakgrunn i pålegg fra Miljødirektoratet har Statkraft Energi AS gitt NTNU Vitenskapsmuseet og Fersk -vannsbiologen AS i oppdrag å gjennomføre fiskebiologiske undersøkelser i Beiarelva i perioden 2017 -19 med ... -
Habitat use and depth preferences of sea trout (Salmo trutta) in a Norwegian estuary
Omholt, Vilde (Master thesis, 2020)Brunørreten (Salmo trutta) er en ferskvannsfisk som lever i bekker, elver, innsjøer og marine kystområder. Anadrome individer, ofte kalt sjøørret, har stor variasjon i migrasjonsstrategi og habitatbruk. De fleste større ... -
Home ranges and habitat utilisation of the river-resident Atlantic salmon, Salmo salar, småblank
Eikaas, Linda (Master thesis, 2016)Home ranges and habitat utilisation of the river resident Atlantic salmon, småblank, Salmo salar, in Nord Trøndelag, Norway, were studied by the use of radio telemetry during the period August 2014 to January 2016. The aim ... -
Homing behaviour of Atlantic salmon (Salmo salar) during final phase of marine migration and river entry
Davidsen, Jan Grimsrud; Rikardsen, Audun H.; Thorstad, Eva Bonsak; Halttunen, Elina; Mitamura, Hiromichi; Præbel, Kim; Skardhamar, Jofrid; Næsje, Tor (Journal article; Peer reviewed, 2013-03-11)Little is known about Atlantic salmon behaviour during the last phase of the marine homing migration and subsequent river entry. In this study, 56 adult Atlantic salmon in the Alta Fjord in northern Norway were equipped ... -
How pathogens affect the marine habitat use and migration of sea trout (Salmo trutta) in two Norwegian fjord systems
Lennox, Robert J.; Eldøy, Sindre Håvarstein; Vollset, Knut; Miller, Kristi M.; Li, Shaorong; Kaukinen, Karia H.; Isaksen, Trond Einar; Davidsen, Jan Grimsrud (Peer reviewed; Journal article, 2020)Wild fish are confronting changing pathogen dynamics arising from anthropogenic disturbance and climate change. Pathogens can influence animal behaviour and life histories, yet there are little such data from fish in the ... -
Individual repeatability in marine migratory behaviour: A multi-population assessment of anadromous brown trout tracked through consecutive feeding migrations
Eldøy, Sindre Håvarstein; Bordeleau, Xavier; Crossin, Glenn T; Davidsen, Jan Grimsrud (Journal article; Peer reviewed, 2019)Despite that the study of individual repeatability is a common topic in behavioral ecology, virtually nothing is known about inter-annual variability in the marine migratory behavior of iteroparous salmonids that can ...