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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Lateral view of a Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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Pteronarcys californica (Giant Salmonfly) Stonefly Nymph Pictures

Here are two size classes of Pteronarcys nymphs. These probably represent two different generations. The largest will probably emerge next spring and the other in two years. There is probably another generation, smaller, I did not collect. In a Canadian study they discovered Pteronarcys eggs do not all hatch simultaneously but hatch for a period of nearly two years, making their egg/nymphal life 5 years. The other photo is of a curled nymph, a typical response to disturbance.

This stonefly was collected from the Touchet River in Washington on August 10th, 2011 and added to Troutnut.com by Bnewell on August 10th, 2011.

Discussions of this Nymph

Friday on the South Fork of the Boise
Posted by Bjorntofish on Jul 2, 2012
Last reply on Jul 2, 2012 by Bjorntofish
Friday, the PC stoneflies were hatching and flying midway up the river in the quality stretch of the South Fork of the Boise Rive (Idaho.) The fish seemed to be gorged with nymphs and only wanted the big nymphs fished in the current. We used large black Brooks flies with rubber hackle. They ignored most of the adult flies that fell to the surface. But the big bombers were lumbering over the water all day. Pretty exciting environment for fishing. At one point, I had two crawling on my neck while I was trying to work my drift into a large fish's feeding lane. Life is good.

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Pteronarcys californica (Giant Salmonfly) Stonefly Nymph Pictures

Collection details
Location: Touchet River, Washington
Date: August 10th, 2011
Added to site: August 10th, 2011
Author: Bnewell
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