Quick Tip: Go Below for BWOs

By Scott Richmond

The hatch was over. It was a typical winter blue-winged olive hatch on the Deschutes: started about 1:00, sputtered along for an hour, then faded away.

I let my Parachute Baetis swing down below me, and I could feel it feel it tug in the current while I scanned the river upstream, hoping one last redside would rise and reveal its position. Then my right arm was wrenched, the rod bent double, and the fly line zinged into midriver in a vain attempt to keep pace with a speeding trout. A big redside cleared the water and was gone, taking my fly with him.

It was bigger than any fish we'd hooked that day, and although I'd cast a dry fly, the trout took while it was submerged and dragging.

How come?

Mayflies of the genus Baetis--the primary genus of the winter-hatching mayflies we lump together as "blue-winged olives"--lay their eggs in two ways. Usually an adult spinner drops to the water, dips her abdomen, and releases the eggs. Sometimes, however, the spinners lay their eggs by crawling down rocks into the water and deposit the next generation on the bottom.

Once done (and sometimes before) they end up drifting subsurface in the current, and that's where trout pick them up: subsurface. Since egg-laying often occurs at the same time as a hatch, it's easy to miss this stage. However, the more I fish this hatch, the more I'm convinced that subsurface adult blue-winged olives can be vitally important to trout and fly anglers. Given a choice, most trout--especially big ones--would rather take their food subsurface.

Westflyer Scott Nelson once emailed: "I have nymph fished on numerous occasions on the Deschutes using a bwo 'diving wet fly' as a trailer, only to find that I wouldn't have a chance to fish dry! I would be too busy catching fish to be able change leaders and my fly." He added that he prefers a fly with a slim, olive body with a clear Antron wing. Basically, it's LaFonataine's Diving Caddis adapted to blue-winged olives (many caddis species use the same diving tactic to lay their eggs). I've used a Soft Hackle , but I think Scott Nelson's approach would work better. As he says, "trout just love that flash in the wing."

Scott Richmond is Westfly's creator and Executive Director. He is the author of eight books on Oregon fly fishing, including Fishing Oregon's Deschutes River (second edition).