Blar i forfatter "Hedger, Richard David"

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    • Diving and feeding of adult Atlantic salmon when migrating through the coastal zone in Norway 

      Hedger, Richard David; Kjellman, Mari; Thorstad, Eva Bonsak; Strøm, John Fredrik; Rikardsen, Audun H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-23)
      Atlantic salmon post-spawners from a population in northern Norway were tagged with data storage tags (N = 773), and the depth use and diving behaviour of recaptured individuals within the coastal zone were examined, both on their outward migration to sea (N = 44) and their return to the natal river after overwintering at sea (N = 34). In addition, the stomach contents of 909 returning adults caught ...

    • Diving behaviour of Atlantic salmon at sea: effects of light regimes and temperature stratification 

      Hedger, Richard David; Rikardsen, Audun H.; Strøm, John Fredrik; Righton, David A.; Thorstad, Eva Bonsak; Næsje, Tor (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-04)
      The diving behaviour of adult Atlantic salmon Salmo salar L. post-spawners in the Norwegian and Barents Seas was monitored with pop-up satellite archival tags (PSATs) and data storage tags (DSTs). Salmon from the 3 studied populations showed similar depth use patterns: tagged specimens spent most of their time near the surface (mean of 82% of the time at depths <10 m), with occasional short deep ...

    • Migration and habitat use of the landlocked riverine Atlantic salmon Salmo salar småblank 

      Davidsen, Jan Grimsrud; Eikås, Linda; Hedger, Richard David; Thorstad, Eva Bonsak; Rønning, Lars; Sjursen, Aslak Darre; Berg, Ole Kristian; Bremset, Gunnbjørn; Karlsson, Sten; Sundt-Hansen, Line Elisabeth Breivik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-18)
      “Småblank” is the only population of Atlantic salmon in Europe living its entire life in the river habitat without performing migrations to the sea or lakes. Home range size and habitat use were compared between an unregulated tributary and hydro-power regulated parts of the main river during 2014–2017. In total, 140 småblank were tagged with radio transmitters and tracked for 4–5 months. Tagged ...

    • Redefining the oceanic distribution of Atlantic salmon 

      Rikardsen, Audun H.; Righton, David; Strøm, John Fredrik; Thorstad, Eva Bonsak; Gargan, Patrick G.; Sheehan, Timothy F.; Økland, Finn; Chittenden, Cedar; Hedger, Richard David; Næsje, Tor; Renkawitz, Mark; Sturlaugsson, Johannes; Caballero, Pablo; Baktoft, Henrik; Davidsen, Jan Grimsrud; Halttunen, Elina; Wright, Serena; Finstad, Bengt; Aarestrup, Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-10)
      Determining the mechanisms driving range-wide reductions in Atlantic salmon marine survival is hindered by an insufcient understanding of their oceanic ecology and distribution. We attached 204 pop-up satellite archival tags to post-spawned salmon when they migrated to the ocean from seven European areas and maiden North American salmon captured at sea at West Greenland. Individuals migrated ...

    • Revealing the full ocean migration of individual Atlantic salmon 

      Strøm, John Fredrik; Thorstad, Eva Bonsak; Hedger, Richard David; Rikardsen, Audun H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-14)
      Knowledge of the complete horizontal migration and vertical movements of Atlantic salmon (Salmo salar L.) during the marine phase is important for understanding the link between individual processes and population recruitment. We studied the detailed migration behaviour of six post-spawned adult Atlantic salmon from a North Norwegian river, during the entire ocean migration, by using high-resolution ...