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Upstream migration of Atlantic salmon at a power station on the River Nidelva, Southern Norway
Author(s) -
Thorstad E. B.,
Økland F.,
Kroglund F.,
Jepsen N.
Publication year - 2003
Publication title -
fisheries management and ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 55
eISSN - 1365-2400
pISSN - 0969-997X
DOI - 10.1046/j.1365-2400.2003.00335.x
Subject(s) - hydroelectricity , salmo , hydrology (agriculture) , fishery , environmental science , hydro power , upstream (networking) , fish migration , discharge , geology , geography , fish <actinopterygii> , ecology , drainage basin , geotechnical engineering , biology , environmental engineering , engineering , telecommunications , cartography
The upstream migration of 17 radio‐tagged adult Atlantic salmon, Salmo salar L., past hydroelectric developments on the River Nidelva, Southern Norway, was examined. Salmon migrated quickly from the site of release in the lower part of the river up to the tunnel outlet of Rygene power station, but were substantially delayed at the outlet. The salmon stayed in the outlet area for 0–71 days (median = 20), and mainly took up a position inside the dark power station tunnel. Water discharge in the tunnel was 57–176 m 3 s −1 , while residual flow in the river between the outlet and the dam 2.5 km further upstream was 3 m 3 s −1 . Ten salmon passed the outlet and entered the residual flow stretch, but none passed the dam. Six of the 10 salmon returned to the tunnel outlet. No major migration barriers were identified in the residual flow stretch, suggesting lack of motivation among the salmon to migrate due to either low water discharge compared with the main river, or several minor migration barriers along the river stretch.