Hasil untuk "Norwegian literature"

Øyvind Kvalnes

Øyvind Kvalnes

Øyvind Kvalnes

Øyvind Kvalnes

N. A. Hvidsten, O. H. Diserud, A. J. Jensen et al.

A model that explains 48% of the annual variation in Atlantic salmonSalmo salarsmolt production in the River Orkla, Norway, has been established. This variation could be explained by egg deposition, minimum daily discharge during the previous winter and minimum weekly discharge during the summer 3 years before smolt migration. All coefficients in the model were positive, which indicates that more eggs and higher minimum discharge levels during the winter before smolt migration and the summer after hatching benefit smolt production. Hence, when the spawning target of the river is reached, the minimum levels of river discharge, in both winter and summer, are the main bottlenecks for the parr survival, and hence for smolt production. The River Orkla was developed for hydropower production in the early 1980s by the construction of four reservoirs upstream of the river stretch accessible toS. salar. Although no water has been removed from the catchment, the dynamics of water flow has been altered, mainly by increasing discharges during winter and reducing spring floods. In spite of the higher than natural winter discharges, minimum winter discharge is still a determinant of smolt production. Hence, in regulated rivers, the maintenance of discharges to ensure that they are as high as possible during dry periods is an important means of securing highS. salarsmolt production.

Canada Surveys and Mapping Branch

Miranda Moen

Tim Flohr Sørensen

Ben Jervis

Anders Högberg

Terje Gansum

Frances Lynch

Kazimierz Bielenin, Elżbieta Nosek

Magnus Elfwendahl

Egil Bakka