Along with other restoration measures, the implementation in 1987 of a fish lift at the power plant of the large-scale hydroelectric development of Golfech-Malause, the lowermost major obstacle on the River Garonne (Fig. 1), resulted in numbers ever increasing of returning Atlantic salmon (Salmo salar L.), with up to 600 individuals recorded in 2001 at the video fish-counting station installed upstream of the fish lift.