Blar i Scientific publications på forfatter "Ugedal, Ola"

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    • Bias in estimates of electrofishing capture probability of juvenile Atlantic salmon 

      Hedger, Richard David; Diserud, Ola Håvard; Sandlund, Odd Terje; Saksgård, Laila M.; Ugedal, Ola; Bremset, Gunnbjørn (Journal article; Peer reviewed, 2018)
      We evaluated the effect of the total number of passes used, and the application of block nets, on multi-pass electrofishing removal sampling for estimating juvenile Atlantic salmon (Salmo salar L.) abundance and body size ...

    • Density independent use of shallow riverine areas in juvenile Atlantic salmon 

      Puffer, Michael; Berg, Ole Kristian; Hamnes, Frøydis Bolme; Bentsen, Vidar; Koch, Wouter; Ugedal, Ola; Forseth, Torbjørn; Arnekleiv, Jo Vegar; Einum, Sigurd (Journal article; Peer reviewed, 2018)
      Habitat use of aquatic organisms is essential to evaluate effects of many environmental challenges like effects of hydro-power regulation, where stranding may occur under hydropeaking (rapid dewatering of shallow river ...

    • Effects of water level regulation in alpine hydropower reservoirs: an ecosystem perspective with a special emphasis on fish 

      Hirsch, Philipp E.; Eloranta, Antti; Amundsen, Per-Arne; Brabrand, Åge; Charmasson, Julie; Helland, Ingeborg Palm; Power, Michael John; Sanchez-Hernandez, Javier; Sandlund, Odd Terje; Sauterleute, Julian Friedrich; Skoglund, Sigrid Østrem; Ugedal, Ola; Yang, Hong (Journal article; Peer reviewed, 2017)
      Sustainable development of hydropower demands a holistic view of potential impacts of water level regulation (WLR) on reservoir ecosystems. Most environmental studies of hydropower have focused on rivers, whereas environmental ...

    • Evaluation of genetic effects on wild salmon populations from stock enhancement 

      Hagen, Ingerid Julie; Ugedal, Ola; Jensen, Arne Johan; Lo, Håvard; Holthe, Espen; Bjøru, Bjørn; Florø-Larsen, Bjørn; Sægrov, Harald; Skoglund, Helge; Karlsson, Sten (Peer reviewed; Journal article, 2020)
      Many salmonid populations are of conservation concern, and the release of hatchery-produced juveniles is a frequently used measure to alleviate declines and increase harvest opportunities. While such releases may be of ...

    • Hydropower impacts on reservoir fish populations are modified by environmental variation 

      Eloranta, Antti; Finstad, Anders Gravbrøt; Helland, Ingeborg Palm; Ugedal, Ola; Power, Michael (Journal article; Peer reviewed, 2018)
      Global transition towards renewable energy production has increased the demand for newand more flexible hydropower operations. Beforemanagement and stakeholders can make informed choices on potential mitigations, it is ...

    • Ice-dependent winter survival of juvenile Atlantic salmon 

      Hedger, Richard David; Næsje, Tor; Fiske, Peder; Ugedal, Ola; Finstad, Anders Gravbrøt; Thorstad, Eva Bonsak (Peer reviewed; Journal article, 2013)
      Changes in snow and ice conditions are some of the most distinctive impactsof global warming in cold temperate and Arctic regions, altering the environ-ment during a critical period for survival for most animals. Laboratories ...

    • Interactions between local population density and limited habitat resources determine movements of juvenile Atlantic salmon 

      Teichert, Maxim; Foldvik, Anders; Einum, Sigurd; Finstad, Anders Gravbrøt; Forseth, Torbjørn; Ugedal, Ola (Journal article; Peer reviewed, 2017)
      Competition for limited resources and the resulting density-dependent processes are key factors in driving stream salmonid population dynamics. Here we test for the combined effects of density and shelter availability on ...

    • Iteroparity and its contribution to life-history variation in Atlantic salmon 

      Persson, Lo; Raunsgard, Astrid; Thorstad, Eva Bonsak; Østborg, Gunnel Marie; Urdal, Kurt; Sægrov, Harald; Ugedal, Ola; Hindar, Kjetil; Karlsson, Sten; Fiske, Peder; Bolstad, Geir Hysing (Peer reviewed; Journal article, 2023)
      Evolution of iteroparity is shaped by the trade-off between current and future reproduction.We studied variation in iteroparity among 205 050 individual Atlantic salmon caught in 179 rivers spanning 14◦ of latitude. The ...

    • Modelling climate change effects on Atlantic salmon: Implications for mitigation in regulated rivers 

      Sundt-Hansen, Line Elisabeth Breivik; Hedger, Richard David; Ugedal, Ola; Diserud, Ola Håvard; Finstad, Anders G.; Sauterleute, Julian Friedrich; Tøfte, Lena S.; Alfredsen, Knut; Forseth, Torbjørn (Peer reviewed; Journal article, 2018)
      Climate change is expected to alter future temperature and discharge regimes of rivers. These regimes have a strong influence on the life history of most aquatic river species, and are key variables controlling the growth ...

    • Modelling the effect of hydropeaking‐induced stranding mortality on Atlantic salmon population abundance 

      Hedger, Richard David; Sauterleute, Julian Friedrich; Sundt-Hansen, Line Elisabeth Breivik; Forseth, Torbjørn; Ugedal, Ola; Diserud, Ola Håvard; Bakken, Tor Haakon (Journal article; Peer reviewed, 2018)
      Studies of hydropeaking‐induced stranding mortality on fish populations have been confined to analysis of empirical data and/or short‐term hydraulic‐habitat modelling of individual events and are thus limited as to how ...

    • Prospects for the future of pink salmon in three oceans: From the native Pacific to the novel Arctic and Atlantic 

      Lennox, Robert; Berntsen, Johan Henrik Hårdensson; Garseth, Åse Helen; Hinch, Scott G.; Hindar, Kjetil; Ugedal, Ola; Utne, Kjell Rong; Vollset, Knut Wiik; Whoriskey, Frederick G.; Thorstad, Eva Bonsak (Peer reviewed; Journal article, 2023)
      While populations of other migratory salmonids suffer in the Anthropocene, pink salmon (Oncorhynchus gorbusca Salmonidae) are thriving, and their distribution is expanding both within their natural range and in the Atlantic ...

    • Relationship between marine growth and sea survival of two anadromous salmonid fish species 

      Jensen, Arne Johan; Finstad, Bengt; Fiske, Peder; Forseth, Torbjørn; Rikardsen, Audun H.; Ugedal, Ola (Journal article; Peer reviewed, 2017)
      This study found empirical evidence supporting the “growth–survival” paradigm in the marine phase of Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta). The paradigm postulates that larger or faster-growing ...

    • Salmon louse infestation in wild brown trout populations generates multi-modal mixture distributions 

      Diserud, Ola Håvard; Hedger, Richard David; Finstad, Bengt; Hendrichsen, Ditte Katrine; Jensen, Arne Johan; Ugedal, Ola (Peer reviewed; Journal article, 2020)
      For successful evaluation of the overall effects of salmon louse infestation on brown trout population dynamics, it is crucial to have a realistic understanding of how lice infestation distributions are generated and how ...

    • Selection against individuals from genetic introgression of escaped farmed salmon in a natural population of Atlantic salmon 

      Wacker, Sebastian; Aronsen, Tonje; Karlsson, Sten; Ugedal, Ola; Diserud, Ola Håvard; Ulvan, Eva Marita; Hindar, Kjetil; Næsje, Tor (Peer reviewed; Journal article, 2021)
      The viability of wild Atlantic salmon populations is threatened by genetic introgression from escaped farmed salmon. Farmed Atlantic salmon are genetically improved for important commercial traits and a life in captivity ...