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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

Dorsal view of a Grammotaulius betteni (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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.

Smoky float down the Yakima Canyon

Smoky float down the Yakima Canyon

By Troutnut on September 11th, 2020
With limited weekends remaining for fishing before October gets really busy, my wife and I braved the smoke to float the Yakima Canyon from mile 20 down to Red's. We found very few steadily rising fish, just small ones sipping Baetid duns in a couple of spots, and picked up some rainbows up to 14" on miscellaneous attractor dries and nymphs. I've never seen so many deer along the canyon, perhaps a consequence of the fire burning out much of the adjacent habitat and feed a few weeks ago.

I did a fairly poor job of budgeting our time, stopping at every likely-looking seam early in the float and then having to blow through some of the best water in a rush to reach the landing before it was too dark to see. That's what I get for not learning the river yet. There were some nicer fish feeding at dusk and I missed a couple strikes, but I didn't have time to stick around and keep working on them.

Photos by Troutnut from the Yakima River in Washington

The Yakima River in Washington
The Yakima River in Washington
The Yakima River in Washington
The Yakima River in Washington

Closeup insects by Troutnut from the Yakima River in Washington

20
Baetis tricaudatus (Blue-Winged Olive) Mayfly Nymph
Dorsal view of a Baetis tricaudatus (Baetidae) (Blue-Winged Olive) Mayfly Nymph from the Yakima River in Washington

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