The migratory fish, such as Atlantic salmon, are born in the Dordogne, leave for the ocean for a few years and then return to the river. The course becomes more complicated when you have to swim upstream and dams now punctuate the Dordogne.
– Lisa Guinic
The new Mauzac-et-Grand-Castang fish pass, near Lalindelaunched on June 17, 2020, was inaugurated this Thursday, September 15, 2022 – after two years of the Covid-19 epidemic.
Pass the obstacle of the dam
The purpose of the fish pass is to “get the fish over an obstacle”begins Thomas Régnier, environmental engineer at EDF Hydro, organization behind the building. “The drop height [du barrage] prevents fish from move from downstream to upstream [de la rivière]“he adds.
– Lisa Guinic
The professional compares the fish pass to “a kind of stairs”. “Its steps are calculated so that, hydraulically and biologically, they correspond to the swimming ability of all fish.”
22 pools
From bleaks of 10 cm to catfish of 2.20 m, passing of course by the great migrants, such as salmon, shad and lamprey. 22 multi-species ponds were thus created on the right bank of the dam to cover the six meters drop of the Dordogne.
– Lisa Guinic
The spectacle becomes even more striking, under the feet. Yohann Bappel, from the Migado association, Migrateurs Garonne Dordogne Charente Seudre, invites visitors to descend a steep staircase to admire the fish pass at water level. He calls her affectionately “the bunker”.
– Lisa Guinic
fish count
“The peculiarity of this passexplains Yohann Bappel, head of control stations for the Dordogne team : two windows and two video acquisitions different. The top camera films the entire window and the bottom camera is much more precise, with high magnification. Yohann Bappel thus counts, each day, the number of fish going up the Dordogne through the pass.
– Lisa Guinic
As a simple visitor, the “bunker” inevitably impresses. Pauline, 23, is accessing this place for the first time. She is struck by “the immensity of the infrastructure, the flow of the passing water, etc.” During the migratory period, towards the end of spring, up to 30,000 fish can pass through this pass during the day.
4.5 million euros of work
Florent Farge, mayor of Mauzac-et-Grand-Castang, is “happy to see the work working”. “Biodiversity is extremely important at presentcontinues the aedile. We know that this technological work of art Is usefull.” The work to build this new fish pass was entirely carried out by EDF Hydro. They represent 4.5 million euros of investment.
– Lisa Guinic