Pygmy Whitefish
Limiting Factors
Pygmy
Whitefish may be found in two distinct habitat types - the deep water of cold deep lakes and fast cold rivers. Their use of deep water locations make
Pygmy Whitefish relatively isolated from human disturbance. The populations in Waterton Lake and Lake Athabasca may not be large but they are well buffered from direct human disturbance. However, these populations may be affected by the warming that has occurred since the last ice age. The effects of warmer water temperatures have not been studied but warmer water may force
Pygmy Whitefish to compete with other species in habitats previously unused by sympatric species such as
Mountain Whitefish. Stocking with
non-native stocks may also negatively affect Pygmy Whitefish. Stocking of
non-native fish has occurred in both Waterton Lake and the Athabasca River during this century.
One of the limiting factors for Pygmy Whitefish in the Athabasca River may be their ability to compete with
Mountain Whitefish. Where Pygmy Whitefish have been collected in the upper Athabasca River, they have been out numbered by one or two orders of magnitude by
Mountain Whitefish. This indicates that both species occupy spatially overlapping habitats and that
Pygmy Whitefish are less successful in these habitats than Mountain
Whitefish. Any additional environmental stresses such as habitat degradation or increases in water temperature may result in decreased competitive ability by
Pygmy Whitefish. The Athabasca River watershed is impacted by a variety of industrial developments including logging, oil and gas exploration and development, and mining. While it is not known how sensitive
Pygmy Whitefish are to this type of habitat degradation, some scientists believe that damage to rearing habitat in Jasper National Park has affected the
Pygmy Whitefish in the Snake Indian River.