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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.

Stream photos

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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.

Caddisfly Species Brachycentrus americanus (American Grannom)

Where & when

Time of year : July and August

This species is most prolific in the West and Midwest, but it may still be of concern to fishermen in the East.

Species Range

source

Hatching behavior

Time of day : Morning

Special thanks to Lloyd Gonzales, author of the excellent new book Fly-Fishing Pressured Water, for helping to sort out the Brachycentrus species and common names.

Specimens of the Caddisfly Species Brachycentrus americanus

1 Female Adult

Female Brachycentrus americanus Caddisfly Adult

1 Picture

Female Brachycentrus americanus (American Grannom) Caddisfly Adult

Size 11 mm. Prior to this photo the specimen dropped its large egg mass that was a very dark (almost black) olive sphere almost twice the diameter of the abdomen. Notice the abdomen visible through the wings is both thickened and shortened post egg drop.

Collected October 15, 2011 from the Fall River in California

Added by Entoman on October 21, 2011

2 Larvae

Brachycentrus americanus Caddisfly Larva

18 Pictures

Brachycentrus americanus (American Grannom) Caddisfly Larva

This species of Brachycentrus was extremely common in mid-September kick net samples in the Yakima canyon.

Collected September 12, 2020 from the Yakima River in Washington

Added by Troutnut on September 19, 2020

Brachycentrus americanus Caddisfly Larva

13 Pictures

Both the genus ID (Merritt & Cummins) and species ID (Flint 1984) are pretty confident for this larva, a nice example of a common western caddisfly. It was by far the most abundant insect in my kicknet sample on this trip, and many of the rocks in the fast riffle where I sampled had dozens of these larvae clinging on.

Collected July 6, 2020 from the Dosewallips River in Washington

Added by Troutnut on July 12, 2020

Discussions of Brachycentrus americanus

Brachycentrus americanus on the Lower Sacramento River California

Posted by Troutguide on Oct 29, 2016

Last reply on Oct 29, 2016 by Troutguide

I believe this is the species found in sometimes very large numbers on the Lower Sacramento River in the Redding area. Ten years ago it was present in such large numbers that fishing a fly on the bottom resulted in frequently hooking one of these caddis still in its case. Along with other aquatic insects their numbers have declined to a fraction of once seen. I don't believe the egg Sac dropped by the females to be olive , instread I have seen it to be a bright green. The females seem to oviposit close to the edge of flowing water and not midstream.

Start a Discussion of Brachycentrus americanus

References

Gonzales, Lloyd. 2005. Fly-Fishing Pressured Water. Stackpole Books.
LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.