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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

Dorsal view of a Sweltsa (Chloroperlidae) (Sallfly) Stonefly Nymph from the Yakima River in Washington
This species was fairly abundant in a February sample of the upper Yakima.
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.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Exploring up the Skykomish

Exploring up the Skykomish

By Troutnut on September 9th, 2020
I've been meaning to check out the scenic country headwaters of the Skykomish for a while, more for the scenery and variety than for the fish, which I expected to be mostly the same 6-12" rainbows and coastal cutthroats found in all the other rivers on the west slope of the Washington cascades. I was also looking to practice Euro nymphing some more, and the Foss River has some ideal stretches of pocket water for that. Starting late in the morning, I was successful early and often. Then, toward mid afternoon, the action shut down completely. I went from catching fish in every pocket to seeing no sign of them in extremely inviting pools. The water temperature was optimal, but the fish were just off.

For the last hour of daylight I drove to the South Fork Skykomish and fished a couple of promising pools. Fish finally started rising intensely right at dusk (to what, I'm not sure), and I caught six small rainbows on dries.

Throughout the day there were no noteworthy hatches, but I did find a couple of bugs worth photographing. I'm especially curious what a near-mature Ephemerellid nymph was doing in the river in mid-September, but I've not yet had time to put most of my recently collected specimens under the microscope and see what they are.

Photos by Troutnut from the Foss River and the South Fork Skykomish River in Washington

The Foss River in Washington
The South Fork Skykomish River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
This logjam was a pretty serious obstacle moving upriver... the large log you see on the left is at least 3 feet in diameter.

From the Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
The Foss River in Washington
Sunlight perfectly strikes the trees at a bend in the Foss River in the Washington Cascades.

From the Foss River in Washington

Closeup insects by Troutnut from the Foss River in Washington

Male Doroneuria baumanni (Perlidae) (Golden Stone) Stonefly Adult from the Foss River in Washington
I found this stonefly on some streamside vegetation. I didn't see any in the air in several hours of fishing.
Dorsal view of a Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from the Foss River in Washington
This is a puzzling one to identify and I'm not sure about the species. The maxillary palp is present and segmented, and the maxillary canines are not strongly serrate laterally. I think it's Ephemerella, not Serratella. The ventral lamellae of the gills on abdominal segment 6 have a clear median notch with a depth at least half the length of the lamellae, which points toward a couple of uncommon species (most likely Ephemerella alleni), but the abdominal tubercles and coloration don't fit that species. To add to the confusion, none of the above species are expected to emerge in the fall, as far as I know. I'm going to call this one Ephemerella aurivillii for now, but that's highly uncertain.

Comments / replies

Martinlf
Martinlf's profile picture
Moderator
Palmyra PA

Posts: 3047
Martinlf on Sep 20, 2020September 20th, 2020, 8:33 am EDT
Looks like a fun day. Thanks for posting; I always enjoy seeing NW streams. My nephew lives near Portland, and, although we cancelled this year's tour, we are planning to fish together at least once a year after this one, fire and plague permitting.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell

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