Canada is a nation defined by its vast aquatic environments, bordered by three oceans and containing nearly a quarter of the world’s freshwater reserves. This immense geographic scale supports a diverse and abundant ichthyofauna, with approximately 1,400 species of fish found across marine and inland waters. About 85% of these species reside in marine habitats, while roughly 11% are exclusively freshwater residents, with the remaining 4% moving between the two environments.
Saltwater Fish of Canada’s Coasts
The country’s extensive coastline, touching the Atlantic, Pacific, and Arctic oceans, is home to hundreds of species that complete their entire life cycle in saltwater. The Atlantic coast, which holds the highest number of marine species, is historically known for its groundfish, which live on or near the seabed. Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) were once the foundation of the East Coast fishery, inhabiting the cold shelf waters. Other commercially important groundfish, such as the American Plaice (Hippoglossoides platessoides) and various species of Redfish (Sebastes spp.), populate the Atlantic deeps.
The Pacific coast of British Columbia features a different marine community, characterized by species like the Pacific Halibut (Hippoglossus stenolepis), a large flatfish found in deeper offshore waters. This region also supports a high diversity of Rockfish (Sebastes spp.), with numerous species like Yelloweye Rockfish and Canary Rockfish inhabiting rocky reefs and structures. Arctic marine waters, while having fewer species overall due to the extreme cold, are characterized by cold-adapted residents. The Arctic Cod (Boreogadus saida) is a prominent species in the Beaufort Sea, serving as a significant component of the Arctic food web.
Freshwater Fish of Canada’s Inland Waters
Canada’s interior is dominated by a network of lakes, rivers, and streams that support a freshwater fish population of approximately 177 species. The Salmonidae family, which includes Trout and Char, is particularly widespread in the cold, clear waters of the Boreal and Arctic regions. Lake Trout (Salvelinus namaycush) is a large, predatory species found across Canada in deep, cold oligotrophic lakes. Brook Trout (Salvelinus fontinalis) are native to the eastern provinces and are often found in smaller, oxygen-rich streams.
The Great Lakes and central river systems are home to numerous warm-water and cool-water species. Walleye (Sander vitreus), a member of the perch family, is widely distributed, preferring large, turbid bodies of water. Northern Pike (Esox lucius) is a large, aggressive predator found in shallow, weedy areas across most of the country. Smallmouth Bass (Micropterus dolomieu) and Largemouth Bass (Micropterus salmoides) are common in the warmer waters of Southern Ontario and Quebec. The Lake Sturgeon (Acipenser fulvescens), a primitive and long-lived species, inhabits many large rivers and lakes, including the Great Lakes and the Saskatchewan River system.
Migratory Fish Species
A distinct group of fish in Canada are the diadromous species, which undertake migrations between freshwater and saltwater to complete their life cycles. The majority of these are anadromous, meaning they are born in fresh water, migrate to the sea to mature, and then return to fresh water to spawn. Pacific Salmon species, including Chinook, Sockeye, and Coho, exemplify this pattern, migrating from the Pacific Ocean back to their natal streams in British Columbia. Atlantic Salmon (Salmo salar) follow a similar anadromous pattern in the rivers of Eastern Canada.
Other anadromous species include the American Shad (Alosa sapidissima) and various species of Lamprey, such as the Sea Lamprey, which move inland to spawn. In contrast, the American Eel (Anguilla rostrata) is catadromous, meaning it lives most of its adult life in freshwater rivers and streams but migrates to the ocean to spawn in the Sargasso Sea. These migratory species are ecologically important because they transfer marine nutrients to inland ecosystems when they return to spawn and die.
Commercial and Conservation Status
Canada’s fish populations support a multi-billion dollar commercial fishing industry and a recreational fishing sector. Historically, the Atlantic Cod fishery was foundational, but its collapse in the early 1990s demonstrated the vulnerability of commercial stocks and the need for strong management. Today, the commercial harvest is dominated by high-value shellfish like Snow Crab and Lobster in the Atlantic region, and various species of Pacific Salmon and Halibut on the West Coast.
The conservation status of many Canadian fish stocks is a growing concern, with a significant portion facing management challenges. As of 2023, approximately 16% of key fish stocks were classified in the “Critical Zone,” meaning their abundance is dangerously low, and another 38% had an “Uncertain” status due to insufficient data for a reliable assessment. Species like the White Sturgeon and certain populations of Atlantic and Pacific Salmon are listed as endangered or threatened under the Species at Risk Act. Freshwater fish populations are also under threat from habitat fragmentation by dams, pollution, and invasive species, with some studies indicating that over 50% of Canada’s freshwater species are at risk.
Fisheries and Oceans Canada manages these resources, aiming for a target of having at least 55% of key stocks in the “Cautious” or “Healthy” zones by 2026. Management tools include establishing total allowable catches, closing fisheries, and protecting critical habitats. The sheer scale of Canada’s aquatic environment, coupled with the cumulative effects of climate change and human development, requires continuous and adaptive management strategies to ensure the long-term sustainability of the country’s diverse fish life.