Pygmy Whitefish - Prosopium coulteri
Pygmy Whitefish Color Plate - Pygmy Whitefish Color Plate
General Description
Pygmy whitefish are native to clear, cold lakes of northwest Montana. As the name suggests, they seldom exceed 6-8 inches in length. Consequently, they are seldom seen by Montanans but may provide an important forage fish, especially for large lake and bull trout. They eat crustaceans and aquatic insect larvae and live in the same deepwater habitat as lake whitefish, except in the fall when they spawn in shallow lake or stream waters.
Diagnostic Characteristics
Silvery except for olive brown back. Mouth overhung by snout. Has one flap of skin between nostrils on each side, and a membrane surrounding each eye has a distinct notch below pupil (see Mountain Whitefish for illustration).
Distribution
Montana Range
Migration
Migrates a short distance into tributary streams to spawn.
Habitat
Deep cold-water lakes and their associated tributaries. Spawns in tributary streams.
Food Habits
Feed mainly on zooplankton throughout lives. July-Dec. Flathead Lake study showed these foods to be important; Daphnia Thorata-70%, Epischura-13%, Organic debris-10%, and chironomid larvae-6%.
Ecology
Forage for predator fish.
Reproductive Characteristics
Sexually mature as early as 1 year but mostly at 2+ years. Spawns Nov-Jan, probably during night. Eggs hatch in Spring.
Citations & Sources
- Holton, G. D. 2003. A field guide to Montana fishes. Mont. Dept. Fish, Wildl. Parks, 95 pp.