Lake whitefish are found in many coldwater lakes across northern North American, although most of their range is in Canada. Lake whitefish are traditionally one of Canada's most comercially valuable fish species, although many populations have declined due to the introduction of non-native species such as smelt, overexploitation by fishermen, and degradation by pollution. Lake whitefish diet consists of a wide variety of bottom-living invertebrates and small fishes, with zooplankton occasionally making up a the remainder of the diet.