Compensatory measures for the copper redhorse on the Verchères islands

As part of its project to build a container terminal in Contrecoeur, the Montreal Port Authority (MPA) must obtain all the permits required to carry out the project, including those related to the loss of submerged aquatic grass beds providing essential feeding habitat for adults of the copper redhorse, a fish species designated as threatened under provincial regulations and as endangered under federal regulations. In this context, a fish habitat compensation project has been conceptualized and its implementation is subject to environmental authorizations. Developments to create aquatic grass beds are planned along Île aux Bœufs, part of the Verchères islands in the St. Lawrence River. These projects, which are not designated under the Impact Assessment Act (LC 2019, c. 28, s. 1), will be carried out on federal lands. In accordance with sections 82 and 83 of the Act, before taking any action or making any decision that would allow a project to proceed in whole or in part, the MPA (the authority) must decide whether the project is likely to cause significant adverse environmental effects.

Île aux Bœufs is currently subject to natural erosion and ship-generated wave action. The proposed developments on Île aux Bœufs are located between the southern part of the island and the ship channel. This area is currently highly resistant to the establishment of aquatic plant communities, due to the nature of the substrate (consolidated silty clay) and the effects of ship wake. The proposed measures include the installation of a 327 m rockfill deflector dike upstream of the island, and a 316 m rockfill breakwater parallel to the island. The riprap structures will reduce the effects of ship-generated waves, maintain flow velocities attractive to copper redhorse and eliminate the likelihood of ice loads on the structures. In addition to these structures, it is proposed to add granular materials in the area protected by them, sized according to the shear forces exerted on the shoreline, and planted fascines of American vallisneria (Vallisneria americana) embedded in these materials to serve as primers for the recolonization of new seagrass beds in this more suitable substrate, over a total area of 3.1 ha.

The in-water work required to build the compensation structures on Île aux Bœufs could begin on July 15, 2025, if all the necessary authorizations are received.

More

Latest update

October 9, 2025 - The Montreal Port Authority must determine whether the proposed project, Compensatory measures for the copper redhorse in the Verchères islands, located in Saint-Sulpice, is likely to cause significant adverse environmental effects.

 

The following message was posted on April 29, 2025.

April 29, 2025 - The Montreal Port Authority must determine whether the proposed project, Compensatory measures for the copper redhorse in the Verchères islands, located in Saint-Sulpice, is likely to cause significant adverse environmental effects.

In order to contribute to an informed determination, the Montreal Port Authority invites the public to comment on this determination. All comments received will be considered public and may be published online.

Written comments may be submitted by May 29, 2025 to :

Communications Port de Montréal
2100 avenue Pierre-Dupuis, Montréal
514-283-7050
communications@port-montreal.com.

Participate

Key documents

Key documents
Document number Document title File Date
1 Notice of Determination of MPA, DFO and ECCC - October 9, 2025

Contacts

Port of Montreal (communications)
2100, Pierre-Dupuy avenue, Wing 1
Montréal, Quebec H3C 3R5
Telephone: 514-283-7050
Email: communications@port-montreal.com


Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

  • Location

    • Île aux Boeufs (Quebec)

  • Nature of Activity

    • Other, not otherwise specified

  • Assessment Status

    Completed

  • Start Date

    2025-04-29

  • Proponent

    Montreal Port Authority

  • Authorities

    • Environment and Climate Change Canada
    • Fisheries and Oceans Canada
    • Montréal Port Authority

  • Assessment Type

    Project on federal lands

  • Reference Number

    89492

Nearby assessments

...within 200 kilometres
Report a problem on this page
Date modified: