Protecting over 33,000 freshwater mussels prior to reconstruction work on the bridge

Île-aux-Tourte Bridge Reconstruction - Mussel Relocation

Reconstruction of the Île-aux-Tourtes bridge between Vaudreuil-Dorion and Montreal jeopardized an entire population of freshwater mussels located in the lac des Deux-Montagne sector. Before starting the reconstruction work, authorities carried out a vast operation to relocate 33,735 mussels. Many of these mussels belong to three at-risk species in a precarious situation—the strong-toothed elliptio, the fragile leptodea, and the pink Heelsplitter. The Ministère des Transports et de la Mobilité Durable du Québec (Ministry of Transport and Sustainable Mobility of Quebec) engaged us to help move these invertebrates.

We supervised the relocation operation and manually moved the mussels upstream of the worksite. This would prevent them from being damaged or disturbed by the temporary stone jetties used in bridge construction. Our environmental professionals were on site with our trained free divers, in collaboration with sub-contracted commercial divers. The mussels were moved further north of the lake, in accordance with the conditions issued by the ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks). All the mussels were hand-collected, either by diving or snorkeling, before being relocated.

Our team will be monitoring the relocated freshwater mussels until 2026 to watch over and secure their survival.