This specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
Bnewell on Mar 3, 2013March 3rd, 2013, 10:48 am EST
There are only two Skwala species in NW Montana. Check out the Ph. D. dissertation of Jack Stanford who worked on the Flathead River for several years driving over 100,000 miles. Also check the following: "The Stoneflies of the Rocky Mountains" by Baumann, Gaufin and Surdick, 1977. The Stoneflies of Montana, 1972, Gaufin et al. "The stoneflies of Glacier National Park and Flathead River Basin, Montana, Newell, Baumann and Stanford, 2008, IN, International Advances in Ecology, Zoogeography, and Systematics of Mayflies and Stoneflies, Univ. of California Publ, Entomology, Vol. 128, pages 173-186.
I have many photos of Skwala but don't think any of them are from the Flathead River, Montana.If you want to see specimens visit the Flathead Lake Biological Station at Yellow Bay and see their reference collection and talk to the Director Jack Stanford.
There is a good article in the new FlyFisherman Mag. The Bitterroot gets a good Skwala hatch. My Yakima that I use to guide on in Eastern WA is really featured in the article. What was interesting to me is in the lower elevations like my Yakima they can come off earlier (late Feb./Mar. and in the higher elevations like the Bitterroot going East they come off somewhat later because of water temps. AND...the higher elevation later arriving Skwalas will appear darker than the lower elevation Skwallas. The Yakima bugs are a dirty yellow body, and the Bitterroot dark green to almost black in appearance.
Entoman on Mar 3, 2013March 3rd, 2013, 1:38 pm EST
...the higher elevation later arriving Skwalas will appear darker than the lower elevation Skwalas.
Yes, I've noticed this myself, and they are smaller as well. I have written what I know about this genus in the hatch page that you may find interesting to review. We have the same big pale ones on the Lower Yuba. It is a very significant hatch on this water and it's happening right now.
There are only three species in North America, curvata, compacta and americana. They don't occur together that I'm aware of. Could the color and size contrasts be ascribed to the differences between the species or are they due to thermal/elevation/latitude influences causing variation? I've yet to read or hear an explanation.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
Gillybilly on Mar 4, 2013March 4th, 2013, 5:19 am EST
Awesome! We're having a warm winter here in NW Montana this year and the river temp's are already approaching 40 degrees. I've fished the skwalas here on the North Fork but usually later in March, early April. I wonder if you know if their hatch moves from down stream up as does Salmon Flies? Thanks!
Entoman on Apr 20, 2013April 20th, 2013, 6:13 pm EDT
Welcome to the forum, Gillybilly.
I apologize for the late reply. As to your question, in my experience the answer is no. They seem to prefer certain stretches and will continue their activity there quite awhile. That and being the first big bug of the year is why this is such a great hatch in up cycles of their populations...
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman