Baetis Biot Emerger

The Baetis Biot Emerger  can be adapted to match any mayfly hatch. This version covers most of the BWO species, but is preferably used for the largest in hook sizes 12-14 – like the Baetis and Aurivilli mayflies. I often call the Baetis Biot emerger pattern the R-Emerger.


A basic emerger for the larger sizes of mayflies. It holds the properties i like the most for the hatching BWOs (especially the Baetidae family). It is a floating nymph and is fished rather deep in the film. The nice segmentation of the turkey biot, combined with the buggyness of the thorax and legs, it’s worth a try when your fishing early in the hatch cycle.

The pattern is not very well suited for the second generation BWOs, but good for the larger first generation BWOs  (best for hook sizes 12-14). Vary the color to match the hatch and local variations.


Hook: TMC 200R, size 14
Thread: Uni 8/0, olive
Shuck: Olive and white Antron
Abdomen: Olive turkey biot
Thorax: Olive Squirrel dubbing
Wing: Three natural brown CdC feathers
Legs: Partridge

Materials are listed in order of tying

Fishing tips

Only apply floatant to wing and thorax. Fish dead drift. Also works well when fished as a high floating wet nymph.