Introduced Freshwater Fishes: A Review of the North American Perspective With Emphasis on Canada

Abstract

The introduction of fishes into North America began in the late 1600's. The number of species has increased over the years, with pulses in the late 1800's and following the 1950's. By 1989, there were 45 established exotic fishes in the continental USA, and 16 in Canada. By 1989, the number brought into, invading, or transferred within Canada was 92 species plus 13 subspecies and hybrids. A special situation for Canada is the steady invasion from U.S. waters. Over the years, 38 such species have been identified. A variety of societal pressures led to the introductions, and the species introduced represent a number of realized or potential environmental impacts. Various international, national, state and provincial agencies or programmes have developed to investigate introductions and/or judge individual applications for the importation or transfer of live fishes. The number and nature of species being moved is still not well known. For Canada, 125 forms (species, hybrids, selected strains) which fit the new definition of Introduced are summarized by province and mode of introduction.