From: "Sonja Amoser" <[EMAIL PROTECTED]>
New article:
Eva B. Thorstad, Finn Økland, Bengt Finstad, Rolf Sivertsgård, Pål Arne
Bjørn & R. Scott McKinley (2004): Migration speeds and orientation of
Atlantic salmon and sea trout post-smolts in a Norwegian fjord system.
Environmental Biology of Fishes 71(3), 305-311
Abstract:
We recorded the observed and actual swimming speeds of Atlantic salmon
and sea trout post-smolts in a Norwegian fjord system, and initiated
studies on the orientation mechanisms of the post-smolts. We tracked
Atlantic salmon and sea trout with acoustic transmitters for up to 14 h
after release. The actual swimming speed and direction of a fish
relative to the ground is the vector sum of the observed movements of
the fish and the movements of the water. We determined actual swimming
speeds and directions of the post-smolts, which reflect their real
swimming capacities and orientation, by corrections for the speed and
direction of the water current. The post-smolts were actively swimming.
The observed direction of movement was dependent on the actual movement
of the fish and not the water current. Water currents were not
systematically used as an orientation cue either in Atlantic salmon or
sea trout, as the actual movements were random compared to the direction
of the water current. The actual movement of sea trout were in all
compass directions, with no systematic pattern. The Atlantic salmon also
moved in all compass directions, but with the lowest frequency of actual
movement towards the fjord.
Mag. Sonja Amoser
Institut of Zoology, University of Vienna
Althanstrasse 14, 1090 Vienna, Austria
Tel: +43-1-4277-54515
Mail: [EMAIL PROTECTED]
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