Browsing Brage IMR by Author "Johnsen, Geir Helge"
Now showing items 1-4 of 4
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A conservation plan for Atlantic salmon (Salmo salar) and anadromous brown trout (Salmo trutta) in a region with intensive industrial use of aquatic habitats, the Hardangerfjord, western Norway
Skaala, Øystein; Johnsen, Geir Helge; Lo, Håvard; Borgstrøm, Reidar; Wennevik, Vidar; Hansen, Michael Møller; Merz, Joseph E.; Glover, Kevin A.; Barlaup, Bjørn T. (Journal article; Peer reviewed, 2013-10-15)Extensive use of aquatic habitats, mainly for hydropower and aquaculture, has a negative impact on anadromous salmonid populations of the Hardangerfjord region, western Norway. High infection levels of salmon lice, and ... -
Increased growth rate in Atlantic salmon parr by using a two-colour diet
Holm, Jens Christian; Jakobsen, Per J.; Johnsen, Geir Helge (ICES CM Documents;1985/F:17, Working paper, 1985)Fishes hunting by sight are known to pay a cost of confusion when faced with high densities of uniform food particles. In such instances, awareness of other stimuli reduces feeding efficiency such that the fishes prefer ... -
Multi-decadal warming of Atlantic water and associated decline of dissolved oxygen in a deep fjord
Aksnes, Dag Lorents; Aure, Jan; Johansen, Per-Otto; Johnsen, Geir Helge; Salvanes, Anne Gro Vea (Journal article; Peer reviewed, 2019)Previous studies have shown decline in dissolved oxygen of the ocean basins. A hypothesis for this development is that ocean warming through increased stratification has caused reduced ventilation of the interior ocean. ... -
Prioriterte strakstiltak for sikring av ville bestander av laksefisk i Hardangerfjordbassenget i påvente av langsiktige forvaltningstiltak
Skaala, Øystein; Johnsen, Geir Helge; Barlaup, Bjørn T. (Rapport fra Havforskningen;Nr.10-2010, Working paper, 2010-10)