Fishing report: Mayfly hatch time |

Fishing report: Mayfly hatch time

Kirk Webb
Special to The Aspen Times
Aspen, CO Colorado

BASALT – The Roaring Fork Valley’s first mayfly hatch of the year, the Blue Wing Olive, is under way along the Colorado and Roaring Fork Rivers.

It’s an exciting time of year and for fly fishers marks the official beginning of spring. Anglers are busy; trading skis and boards for rods and waders. It’s no big secret either as to how good the fishing really is right now. It’s dynamite! Big rainbows and browns are showing up in nets regularly. This is arguably the single best time of year to target, hook and land your largest fish of the year.

After fishing midges all winter, Blue Wing Olive mayflies appear huge, not only to us but to the fish! Blue Wing Olives (BWOs) prefer to hatch on warmer, overcast days, and are most often seen midday from noon to 3 p.m.

Stalking trout with dry flies is the angler’s parallel to hitting the perfect powder day on the mountain; it’s as good as it gets. Prior to the hatch, fish will be focused on BWO nymph imitations. Some of my favorites include: Pheasant Tails, STDs and BLMs in sizes 18-20.

As the day begins to warm, fish will slowly move into shallower riffles. At this point, fish will feed on BWO emergers; a critical stage of their life where they are most vulnerable to the trout. Emergers are the transitional stage of life where the nymphs begin to split their wing case, float to the water’s surface and then hatch into an adult, winged insect.

Deciphering the rise forms of the trout is one of the key elements in being successful on the water. Often anglers will cast to “rising” trout using a dry fly that matches the adult dun perfectly, only to get refusal after refusal. When this happens you can be willing to bet that the fish are keyed on emergers, not adults. Keep a sharp eye on the fish and study their rise forms. Are you seeing noses poking up through the surface or are you seeing a dorsal fin followed by a tail, indicating an emerger rise? Most guides generally kill two birds with one stone by fishing a BWO dry fly trailed by a BWO emerger. This allows you to have a visual indicator, while also presenting an emerger.

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