Downstream displacement of post‐emergent brown trout: effects of development stage and water velocity
Abstract:Brown trout Salmo trutta were introduced at hatching into distinct sections of two parallel artificial channels, one with a constant low velocity (control) and one with velocity changes (experimental), at such times as to produce 12, 3 and 0 day old fish (age after emergences) when the velocity was changed in the experimental channel. This experimental design was repeated in 2002 and 2003 at comparable dates. Young brown trout were sensitive to an increased water velocity for 5 to 6 days after emergence. Water velocity modified the displacement patterns qualitatively but not quantitatively. Eighty per cent of fish moved downstream at all water velocities. Velocity changes, however, advanced the time by which 80% of the fish had displaced downstream.
Document Type: Regular Paper
Affiliations: 1: Cemagref, Freshwater Biology Research Unit, 3 bis quai Chauveau, CP 220, 69336 Lyon cedex 09, France and 2: INRA, Hydrobiology Research Unit, B.P. 3 64310 Saint Pée sur Nivelle France
Publication date: September 1, 2005