The wetlands around Lake Saint-Pierre harbour a great diversity of aquatic plants and benthic fauna. These habitats provide food for numerous species of fish.
The Spotted Sandpiper struts rapidly along the banks looking for insects, worms, gastropods and crustaceans. It sometimes also catches small fish.
The Great Blue Heron stands without moving, searching the surface of the water for fish.
The Black-Crowned Night Heron is another common wading bird of Lake Saint-Pierre. It uses its long, pointed beak to seize its prey.