Fish Rescue at the Chambly Canal
Chambly Canal National Historic Site
At the end of every navigation season, the water level in the Canal is lowered so our staff can carry out essential maintenance to keep the locks in good working order. The water is gradually lowered using valves through which the fish in the Canal find their way toward the nearest body of water. However, even though most of the fish get out of the Canal, sometimes several of them get trapped in residual pools. When work needs to be done in these areas, human intervention is required to allow them to return to the river. This is what happened in Chambly!
Complete drying and rehabilitation of locks
Two exercises to rescue and relocate fish trapped in residual pools during the drying of the chambers of Locks Nos. 1, 2, 3 and 9 were carried out this fall. Before lowering the water level, Parks Canada made sure that the fish trapped in pools were collected, identified and relocated to the the Richelieu River where the conditions were favourable for their survival and free movement, while reducing the stress and harm to them.
Fish recrue at Chambly Canal
How do we move the fish?
Parks Canada approached COVABAR, the Comité de concertation et de valorisation du bassin de la rivière Richelieu, to rescue the fish. This teamwork allowed for the effective tracking of the species that were picked up and relocated.
A team from COVABAR descended into the locks and picked up the fish using a platform and nets. The fish that were collected and identified were placed in containers, which were then removed from the locks with a boom truck.
More then 50 000 fish from 21 different species were identified and relocated. Among these species were yellow perch, smallmouth bass and pumpkinseed. One copper redhorse, a species designated “threatened” under the Government of Quebec’s Act respecting threatened or vulnerable species and “endangered” under the Government of Canada’s Species at Risk Act, was also observed. However, handling the fish to confirm the good news could have endangered its life.
The success of the operation depended largely on how quickly the teams in the field could work. The primary focus was therefore on the rapid release of the individuals into the river. In addition, the bins were not emptied directly into the basin, but rather were gently submerged. This reduces stress and shock, which could lead to fish mortalities. After being submerged, the weakest individuals were reoxygenated. This technique consisted of holding the fish and moving it back and forth in the water until it regained strength.
One of the factors that was most closely monitored during the operation was the oxygen concentration in the water, particularly in Lock No. 1 because a large number of fish had been detected there during previous inspections. The experts on site made considerable efforts to record the oxygen meter readings to ensure that the oxygen concentration did not fall below a critical level, in which case the emergency procedure would have had to be deployed.
This initiative is part of the environmental mitigation measures that Parks Canada is putting in place when working.
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