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.

Stream photos

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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington

This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.

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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.

Baetidae

Baetis (Blue-Winged Olive) Mayfly Nymph

4 Pictures

Dorsal view of a Baetis (Baetidae) (Blue-Winged Olive) Mayfly Nymph from Cayuta Creek in New York

Collected April 13, 2007 from Cayuta Creek in New York

Added by Troutnut on April 22, 2007

Collected April 13, 2007 from Cayuta Creek in New York and added by Troutnut on April 22, 2007

Earlfishman
Posts: 17

Earlfishman on Apr 23, 2007April 23rd, 2007, 3:05 pm EDT

This one looks like an almost ready to emerge male Baetis sp., but I can't be 100% based on the pictures and I definitely can't go any further than that.

As a side note, if anyone is interested in a good key to the larvae of Baetidae, search google for "EPA photographic Baetidae key" and click on the PDF at the EPA site (direct link to the PDF here). The key has some good photos and works very well for the eastern U.S.

Martinlf

Moderator
Palmyra PA

Posts: 3047

Martinlf on Apr 24, 2007April 24th, 2007, 2:14 am EDT

Wow, amazing photos.

"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell

Konchu

Site Editor
Indiana

Posts: 498

Konchu on Apr 24, 2007April 24th, 2007, 6:14 am EDT

Could even be a Pseudocloeon/Labiobaetis species...

Earlfishman: Thanks for the link to the great baetid key!!!

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Apr 24, 2007April 24th, 2007, 6:44 am EDT

Excellent link Earl! I'll be using that one a lot.

Following it through for this specimen leads me to Baetis too.

Does anyone have the Baetis species key the PDF mentions as the most recent (Weirsema et al 2004)? Is it worth a trip to the library?

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist

Konchu

Site Editor
Indiana

Posts: 498

Konchu on Apr 24, 2007April 24th, 2007, 2:52 pm EDT

Worth the trip to the library.