Construction of fish migration passes

4 February 2021

To mitigate the jetty’s impacts on fish and fish habitat, the Nouvel Horizon Saint-Laurent (NHSL) Corporation is building two passes that will be in place for next spring’s migration and fish spawning period. 

When designing the passes, NHSL considered many parameters to reproduce the ideal fish migration conditions: 

• A constant flow in the area, with a speed that does not exceed 0.8 to 1.2 m/s. 

• A minimum water depth of 0.6 m during low-flow periods, and the width of each pass must be at least 5 m.  

The passes will be created directly in the natural substratum found across the Île des Sœurs jetty. 

Once these corridors are in place, instruments will be set up to: 

• Perform biological monitoring with fish counts.  

• Monitor the effectiveness of hydraulic conditions.  

Which fish species live in the area? 

Over 40 species of fish live in the Greater La Prairie Basin (where the river widens between the Lachine Rapids and the Victoria Bridge):  

• smallmouth and largemouth bass  

• lake sturgeon  

• walleye and sauger 

• longnose sucker 

• yellow perch 

All of these fish tend to inhabit the river where the work is located.  

Visit the Environment section of the Champlain Bridge deconstruction project to know more about this!