• Annual and diel activity cycles of a northern population of the large migratory cyprinid fish asp (Leuciscus aspius) 

      Kärgenberg, Einar; Sandlund, Odd Terje; Thorstad, Eva Bonsak; Thalfeldt, Mart; Økland, Finn; Kaasik, Ants; Tambets, Meelis (Peer reviewed; Journal article, 2022)
      Little is known about the exact movement parameters of migratory cyprinids listed as conservation priorities. A northern population of predatory asp, listed on the Bern Convention Appendix III, was studied in a near ...
    • Atferd hos rømt oppdrettslaks i Sunndalsfjorden 

      Solem, Øyvind; Hedger, Richard; Urke, Henning Andre; Kristensen, Torstein; Økland, Finn; Ulvan, Eva Marita; Uglem, Ingebrigt (NINA rapport;805, Research report, 2012)
      Solem, Ø., Hedger, R., Urke, H.A, Kristensen, T., Økland, F., Ulvan, E. & Uglem, I. 2012. Atferd hos rømt oppdrettslaks i Sunndalsfjorden - NINA Rapport 805, 23 sider. Hensikten med prosjektet var å undersøke overlevelse, ...
    • Atferd og spredning av rømt oppdrettslaks og villaks i Namsen og andre elver. Resultater fra merking av laks i Namsfjorden og Vikna 

      Næsje, Tor; Ulvan, Eva Marita; Sandnes, Tomas*; Jensen, Jenny; Staldvik, Frode; Holm, Ragnar*; Landstad, Jan Arild*; Økland, Finn; Moe, Karina; Fiske, Peder; Heggberget, Tor Gravråk; Thorstad, Eva Bonsak (NINA Rapport;931, Research report, 2013-04)
      Vi undersøkte atferd og spredning av rømt oppdrettslaks og villaks i Namsen og andre elver i Midt-Norge i 2012. Hovedmålsettingen var å skaffe kunnskap slik at man kan gjøre sikrere beregninger av den reelle andelen rømt ...
    • Automatisk posisjonering av akustisk merket smolt i tre dimensjoner – utprøving og evaluering i Mandalsvassdraget. 

      Gjelland, Karl Øystein; Baktoft, Henrik; Økland, Finn; Hedger, Richard David; Forseth, Torbjørn (NINA rapport;1072, Research report, 2014)
      Et nytt system som kan gi tredimensjonal (3D) posisjonering av smolt ved hjelp av trådløs akustisk telemetri ble utprøvd og evaluert i Mandalsvassdraget sommeren 2014. I forsøkene ble signaler fra akustiske merker logget ...
    • Behaviour and mortality of downstream migrating Atlantic salmon smolts at a small power station with multiple migration routes 

      Kärgenberg, Einar; Thorstad, Eva Bonsak; Järvekülg, Rein; Sandlund, Odd Terje; Saadre, Ene; Økland, Finn; Thalfeldt, Mart; Tambets, Meelis (Journal article; Peer reviewed, 2019)
      Salmon smolts were released upstream of a run‐of‐river hydropower site and recaptured downstream for inspection. Descending fish behaviour through three possible migration routes (turbines, fishway, spillway) was analysed ...
    • Beskatning og bestandsstørrelse av laks i Namsenvassdraget 

      Thorstad, Eva Bonsak; Fiske, Peder; Staldvik, Frode; Økland, Finn (NINA rapport;747, Research report, 2011)
      Thorstad, E.B., Fiske, P., Staldvik, F. & Økland, F. 2011. Beskatning og bestandsstørrelse av laks i Namsenvassdraget 2010. - NINA Rapport 747: 1-32. Undersøkelser av beskatningsrater og bestandsstørrelse i Namsenvassdraget ...
    • Biotic and abiotic determinants of the ascent behaviour of adult Atlantic salmon transiting passable waterfalls 

      Lennox, Robert J.; Thorstad, Eva Bonsak; Diserud, Ola Håvard; Økland, Finn; Cooke, Steven J.; Aasestad, Ingar; Forseth, Torbjørn (Journal article; Peer reviewed, 2018)
      The spawning migration of Atlantic salmon has been characterized by tracking salmon carrying electronic tags as they ascend rivers, but still little is known about how natural obstacles such as waterfalls influence migratory ...
    • Can Energy Depletion of Wild Atlantic Salmon Kelts Negotiating Hydropower Facilities Lead to Reduced Survival? 

      Baktoft, Henrik; Gjelland, Karl Øystein; Szabo-Meszaros, Marcell; Silva, Ana T.; Riha, Milan; Økland, Finn; Alfredsen, Knut; Forseth, Torbjørn (Peer reviewed; Journal article, 2020)
      Repeat spawners constitute an important component of Atlantic salmon populations, but survival of post-spawning individuals (kelts) are often compromised by anthropogenic structures such as hydropower plants (HPPs). Potential ...
    • Comparing dominance relationships and movement of native marble trout (Salmo marmoratus) and introduced rainbow trout (Oncorhynchus mykiss) 

      Pengal, Polona; Cokan, Blaz; Økland, Finn; Höjesjö, Johan; Tambets, Meelis; Thorstad, Eva Bonsak (Peer reviewed; Journal article, 2023)
    • Contrasting structural complexity diferentiate hunting strategy in an ambush apex predator 

      Říha, Milan; Gjelland, Karl Øystein; Děd, Vilém; Eloranta, Antti; Rabaneda-Bueno, Ruben; Baktoft, Henrik; Vejřík, Lukáš; Vejříková, Ivana; Drastik, Vladislav; Šmejkal, Marek; Holubová, Michaela; Jůza, Tomáš; Rosten, Carolyn; Sajdlová, Zuzana; Økland, Finn; Peterka, Jiří (Peer reviewed; Journal article, 2021)
      Structural complexity is known to influence prey behaviour, mortality and population structure, but the effects on predators have received less attention. We tested whether contrasting structural complexity in two newly ...
    • Development and testing of attachment methods for pop-up satellite archival transmitters in European eel 

      Økland, Finn; Thorstad, Eva Bonsak; Westerberg, Håkan; Aarestrup, Kim; Metcalfe, Julian D. (Peer reviewed, 2013)
      Background: Four methods for attaching pop-up satellite transmitters to European eel were tested in the laboratory by recording long-term tag retention, growth and survival; short-term behavioral responses; and physical ...
    • Effects of a dispersal barrier on freshwater migration of the vimba bream (Vimba vimba) 

      Tambets, Meelis; Kärgenberg, Einar; Thorstad, Eva Bonsak; Sandlund, Odd Terje; Økland, Finn; Thalfeldt, Mart (Journal article; Peer reviewed, 2018)
      To study the effects of a dispersal barrier on migration of the semi-anadromous vimba bream in the Pärnu River, Estonia, we tagged thirty fish with acoustic transmitters and released above the barrier. Tagged fish showed ...
    • Empirical observations of the spawning migrationof European eels: The long and dangerous roadto the Sargasso Sea 

      Righton, David; Westerberg, Håkan; Feunteun, Eric; Økland, Finn; Gargan, Patrick G.; Amilhat, Elsa; Metcalfe, Julian; Lobon-Cervia, Javier; Sjöberg, Niklas; Simon, Janek; Acou, Anthony; Vedor, Marisa; Walker, Alan; Trancart, Thomas; Brämick, Uwe; Aarestrup, Kim (Journal article; Peer reviewed, 2016)
      The spawning migration of the European eel (Anguilla anguilla L.) to the Sargasso Sea is one of the greatest animal migrations. However, the duration and route of the migration remain uncertain. Using fishery data from ...
    • Escaped farmed Atlantic salmon in Norwegian rivers during 1989–2013 

      Diserud, Ola Håvard; Fiske, Peder; Sægrov, Harald; Urdal, K.; Aronsen, Tonje; Lo, Håvard; Barlaup, Bjørn Torgeir; Niemela, Eero; Orell, P.; Erkinaro, J.; Lund, Roar A.; Økland, Finn; Østborg, Gunnel Marie; Hansen, Lars Petter; Hindar, Kjetil (Journal article; Peer reviewed, 2019)
      We report on the data from an extensive monitoring programme for the occurrence of escaped farmed Atlantic salmon (Salmo salar) in Norwegian rivers for 25 years. This monitoring started as a 3-year research programme in ...
    • European eel Anguilla anguilla compromise speed for safety in the early marine spawning migration 

      Lennox, Robert J.; Økland, Finn; Mitamura, Hiromichi; Cooke, Steven J.; Thorstad, Eva Bonsak (Journal article; Peer reviewed, 2018)
      There are substantial benefits to potential fitness conferred to animals that undertake migrations. However, animals must make compromises to maximize survival and compensate for the risks associated with long-distance ...
    • Forslag til overvåkingssystem for sjøørret 

      Finstad, Bengt; Ulvan, Eva Marita; Jonsson, Bror; Ugedal, Ola; Thorstad, Eva Bonsak; Hvidsten, Nils Arne; Hindar, Kjetil; Karlsson, Sten; Uglem, Ingebrigt; Økland, Finn (NINA rapport;689, Research report, 2011)
      Finstad, B., Ulvan, E.M., Jonsson, B., Ugedal, O., Thorstad, E.B., Hvidsten, N.A., Hindar, K., Karlsson, S., Uglem, I. & Økland, F. 2011. Forslag til overvåkingssystem for sjøørret. - NINA Rapport 689. 53 s. Prosjektets ...
    • Heart rate and swimming activity as stress indicators for Atlantic salmon (Salmo salar) 

      Svendsen, Eirik; Føre, Martin; Økland, Finn; Gräns, Albin; Hedger, Richard David; Alfredsen, Jo Arve; Uglem, Ingebrigt; Rosten, Carolyn; Frank, Kevin; Erikson, Ulf Gøran; Finstad, Bengt (Peer reviewed; Journal article, 2020)
      We investigated the relationship between telemetry measurements of heart rate and swimming activity and the physiological status in farmed Atlantic salmon (Salmo salar) to assess the potential to use telemetry measurements ...
    • Impacts of a weir and power station on downstream migrating Atlantic salmon smolts in a German river 

      Havn, Torgeir Børresen; Thorstad, Eva Bonsak; Borcherding, Jost; Heermann, Lisa; Teichert, Maxim A. K.; Ingendahl, Detlev; Tambets, Meelis; Sæther, Stein Are; Økland, Finn (Peer reviewed; Journal article, 2020)
      Weirs are barriers built across rivers for a wide range of other purposes than hydropower production. Like hydropower installations, weirs can negatively impact fish migrations. Downstream migration and mortality of Atlantic ...
    • In situ measurement of salinity during seaward migration of Atlantic salmon post‑smolts using acoustic transmitters with data‑storage capabilities and conventional acoustic transmitters 

      Mitamura, Hiromichi; Thorstad, Eva Bonsak; Uglem, Ingebrigt; Økland, Finn (Journal article; Peer reviewed, 2017)
      Background: Development of miniature acoustic transmitters and data-storage tags has provided new insights into ecology of free-ranging aquatic animals. In this study, we used a data-storage-type and a conventional acoustic ...
    • Innsig og fangst av villaks og rømt oppdrettslaks til elvene rundt Trondheimsfjorden. Rapport for 2012 

      Næsje, Tor; Ulvan, Eva Marita; Jørrestol, Arne; Fiske, Peder; Økland, Finn; Hvidsten, Nils Arne; Heggberget, Tor Gravråk (NINA Rapport;977, Research report, 2013)
      Villaksinnsiget til Trondheimsfjorden i 2012 var lavere enn estimatene i de to foregående årene, men av samme størrelse som i 2007-2009. I 2012 økte andel oppdrettslaks i fangstene gjennom sesongen, men innslaget totalt ...