Freshwater Fisheries in Canada: Historical and Contemporary Perspectives on the Resources and Their Management

Chapter 1: Zoogeography of the Freshwater Fishes of Canada

Nicholas E. Mandrak, R. Allen Curry, Pierre Dumont, James D. Reist, Eric B. Taylor, and Douglas A. Watkinson


The freshwater fish fauna of Canada has been profoundly shaped, and limited, by events during and following the last Ice Age. Currently, there are 201 native species, and 21 established nonnative species known from the freshwaters in Canada (Appendix, Mandrak 2023, this volume; taxonomy, scientific, and common names according to Page et al. (in press) unless otherwise noted). This includes species that spend all, or a substantial portion of, their lives in freshwaters. Prior to the publication of the definitive Freshwater Fishes of Canada (Scott and Crossman 1973), comprehensive checklists of freshwater fishes in Canada listed 44 species in 1700, 72 species in 1836, 63 species in 1897, 145 species in 1907, 228 species in 1913, 177 species in 1947, 187 species in 1958, 186 species in 1967, and 183 species in 1969 (Crossman 1969). These changes were the result initially of the increasing frequency and geography of surveys and, subsequently, of taxonomic revisions of our native fauna and establishment of nonnative species. Scott and Crossman (1973) listed 176 native and four nonnative species. Since then, 17 additional nonnative species have become established (see Mandrak 2023, this volume), and 24 native species have been “gained” (Table 1). Of the “gained” native species, eight species were result of taxonomic splits of one species into two species, six were rare with a limited range and only collected since 1973, five were previously confused with other native species, five were the result of populations elevated to full species status, and one species included here (extirpated paddlefish) was not included in Scott and Crossman (1973). Of the eight major drainage basins in Canada, the greatest increase in the overall number of species present since 1973 has been in the Great Lakes drainage (17 species), followed by Pacific (16), Western Hudson Bay (12), St. Lawrence (11), Maritimes (6), Missouri (5), and Eastern Arctic/Eastern Hudson Bay (2) (Table 2). Undoubtedly, our knowledge of the Canadian native freshwater fish fauna will continue to evolve as our understanding of fish systematics evolves, particularly with new phylogenetic methods that incorporate genomics. The number of Canadian freshwater fishes will likely increase not only as a result of a better understanding of fish phylogeny at the molecular level, but, unfortunately, as a result of the ongoing illegal introduction of nonnative species into Canadian waters (Mandrak 2023), likely to be exacerbated under climate change (e.g., Campbell et al. 2022).

This chapter reviews the composition, origin, and distributional patterns of freshwater fishes nationally and regionally in Canada. The regions include the Maritimes, Great Lakes–St. Lawrence, eastern Arctic (including eastern Hudson Bay), western Hudson Bay, Missouri, Pacific, and western Arctic (including northwestern Hudson Bay and the Arctic Archipelago).