The ecosystem of the Lake Saint-Pierre archipelago stands out for its significant wildlife diversity. The territory is home to 79 species of fish, representing approximately 70% of the freshwater species found in Quebec. The waters of the lake and the St. Lawrence River are notably home to walleye, sauger, northern pike, smallmouth bass, largemouth bass, sturgeon, carp, and muskellunge.
Aquatic habitats consist of shallow waters, channels, dense weed beds, and reed edges. Northern pike favor the weed beds of Grande Baie and Baie de l’île de Grâce, as well as submerged tree structures. Walleye and sauger frequent sand and rock
+ + See more− − See less
bottoms, submerged stone dams, river mouths, and shipping channels. Bass are concentrated in calm bays, rocky structures, and aquatic vegetation.
Composed of wetlands, marshes, and islands subject to spring flooding, the site serves as a natural stopover for migratory birds, hosting up to 290 bird species. The archipelago is home to the largest heronry in North America. Among the avifauna observed in the area are the Great Blue Heron, Green Heron, Black-crowned Night Heron, Great Egret, Bald Eagle, Osprey, Mallard, Green-winged Teal, Caspian Tern, Common Loon, and Belted Kingfisher.