American Springfly - Skwala americana
The Skwala is a colorful stonefly nymph that hatches in early spring when not many other insects are hatching, making it the first large, post-winter meal for trout, and good fishing for fisherman. The Skwala hatch begins as river waters begin to warm, usually the end of February, which provides a pre-runoff fishing opportunity. The Bitterroot River has become a favorite river for the skwala hatch, but many other large Montana rivers such as the Clark Fork River, Blackfoot, Smith, Yellowstone and Madison Rivers contains these insects in large enough numbers to make fishing the hatch worthwhile.
The Skwala hatch begins as river waters begin to warm, usually the end of February and continues through April in dark canyon reaches that remain colder.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Merritt and Cummins (1996) report that members of the families, Perlidae and Perlodidae, are largely predators eating other aquatic invertrebrates, especially Diptera (Chironomidae and Simuliidae, midges and blackflies) and Mayflies.
The Skwala hatch begins as river waters begin to warm, usually the end of February,
- Literature Cited AboveLegend: View Online Publication
- Cummins, K.W. and R.W. Merritt. 1996. Ecology and distribution of aquatic insects. Chapter 6, pages 74-86 in R.W. Merritt and K.W. Cummins (eds.) An Introduction to the Aquatic Insects of North America. Third Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa. 862 pp.
- Additional Sources of Information Related to "Insects"