Browsing NINA Brage by Author "Hedger, Richard David"
Now showing items 1-11 of 11
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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 ... -
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 ... -
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 ... -
Laks i framtidens klima: Kunnskapsoppsummering og scenario med vekt på temperatur og vannføring
Hedger, Richard David; Jonsson, Bror; Kvambekk, Ånund Sigurd; Ekker, Ragnar; Forseth, Torbjørn; Ugedal, Ola; Sundt-Hansen, Line Elisabeth Breivik; Diserud, Ola Håvard (NINA rapport;646, Research report, 2010)Finstad, A.G., Hedger, R., Jonsson, B., Kvambekk, Å.S, Ekker, R., Forseth, T., Ugedal, O., Sundt-Hansen, L. & Diserud, O.H. 2010 Laks i framtidens klima: Kunnskapsoppsummering og scenario med vekt på temperatur og ... -
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, 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 downstream longitudinal effects of frequent hydropeaking on the spawning potential and stranding susceptibility of salmonids
Burman, Anton; Hedger, Richard David; Hellstrom, J Gunnar I; Andersson, Anders G; Sundt-Hansen, Line Elisabeth Breivik (Peer reviewed; Journal article, 2021)Hydropower plant operating conditions are expected to change to be more in tandem with intermittent power production so as to meet the requirements of the Paris Agreement, which in turn may negatively impact ecolog- ical ... -
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 ... -
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 (Peer reviewed; Journal article, 2021)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 ... -
Revealing the full ocean migration of individual Atlantic salmon
Strøm, John Fredrik; Thorstad, Eva Bonsak; Hedger, Richard David; Rikardsen, Audun H. (Journal article; Peer reviewed, 2018)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. ... -
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 ... -
The effects of hydrodynamics on the three-dimensional downstream migratory movement of Atlantic salmon
Silva, Ana T.; Bærum, Kim Magnus; Hedger, Richard David; Baktoft, Henrik; Fjeldstad, Hans-Petter; Gjelland, Karl Øystein; Økland, Finn; Forseth, Torbjørn (Journal article; Peer reviewed, 2019)Anthropogenic structures in rivers are major threats for fish migration and effective mitigation is imperative given the worldwide expansion of such structures. Fish behaviour is strongly influenced by hydrodynamics, but ...