Header image
Enter a name
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.

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.
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.

Male Baetis bicaudatus (BWO) Mayfly Nymph Pictures

Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Dorsal view of a Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Ventral view of a Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska
Ruler view of a Male Baetis bicaudatus (Baetidae) (BWO) Mayfly Nymph from the Gulkana River in Alaska The smallest ruler marks are 1 mm.

This mayfly was collected from the Gulkana River in Alaska on July 17th, 2011 and added to Troutnut.com by Troutnut on July 20th, 2011.

Discussions of this Nymph

Anyone recognize this Baetid nymph?
24 replies
Posted by Troutnut on Jul 20, 2011
Last reply on Jul 21, 2011 by Entoman
There aren't all that many baetids reported from Alaska, but I couldn't figure out what this one is. I didn't have a lot of time to look at keys, but here's the whole list of reported Alaskan baetids, with the ones I could obviously eliminate crossed out (and now some that you've eliminated, too):

Acentrella feropagus
Acentrella insignificans
Acentrella lapponica
Acentrella turbida

Baetis bicaudatus
Baetis foemina
Baetis tricaudatus
Baetis bundyae
Baetis flavistriga

Callibaetis

Diphetor hageni

Plauditus dubius

Procloeon pennulatum

Start a Discussion of Nymph

Male Baetis bicaudatus (BWO) Mayfly Nymph Pictures

Collection details
Location: Gulkana River, Alaska
Date: July 17th, 2011
Added to site: July 20th, 2011
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy