Contained within the 3rd Edition (1957) of the Atlas of Canada is a plate that shows 20 condensed maps with ranges of important inland fish of commercial value found within Canada. The ranges, for the most part, indicate present and usual distribution. Rare or occasional occurrences have not been shown. As there is still much to be learned about the fish species in some parts of Canada, some range limits are hypothetical. It should not be assumed that all species may be found throughout their respective ranges as indicated on these maps. Distribution within their broad ranges is frequently limited to particular but discontinuous habitats.