Aquatic insect hatches and the rhythm of the river |

Aquatic insect hatches and the rhythm of the river

One of John Duty’s favorite things about June in Steamboat Springs is the prolific hatch of an aquatic insect referred to as the yellow sally.

The small stoneflies hatch in profusion and cause trout to feed with abandon.

“They come off heavy and the fish are psyched,” Duty said. “They’re finally eating something that isn’t a tiny midge.”

Duty is co-owner of Bucking Rainbow Outfitters and a student of the Yampa, which flows a block from his fly shop.

The rhythm of summer fishing on the Yampa is dictated by streamflows and water temperatures, which in turn govern the hatches of insects the trout feed on.

This summer, for the first time in five years, those rhythms could return to what long-time residents consider to be “normal.” A winter that saw 430 inches of snow means spring runoff will last longer this summer and change the fishing opportunities in the valley.

For much of the last five years, the river dropped precipitously in mid-June. That resulted in excellent fishing in the town stretch for trout rising to a mayfly known as the pale morning dun, or simply, the PMD.

The PMDs may not be as fishable this summer if the river stays high until early July. Duty’s favorite yellow sallies should still be available for anglers to imitate. Even at relatively high water, fly fishers can cast a dry fly called a “stimulator” upstream into small pockets of calm water along the bank and find trout looking up for small yellow stoneflies.

The tradeoff for missing out on the PMDs this year could come with improved fishing for late afternoon and early evening caddis hatches in July.

Steve Henderson of the Steamboat Flyfisher predicted that the weather in the fifth month of the year will have told the tale for the rest of summer.

“The entire month of May is the determining factor in our hatches,” Henderson said. “We had a ton of snow, but a warm spell could make it come down the rivers quickly. A cool, wet May means it’s going to push the runoff back.”

If cold wet weather persists, that could also push back the arrival in August of the tiny mayflies known as “tricos.”

Last winter’s deep snows also have implications for anglers headed for high country lakes. Some of those lakes won’t be accessible until July.

A handful of fly patterns will cover most fishing situations in the Alpine lakes of the Mount Zirkel wilderness area.

Flies you shouldn’t go without include: Adams dry flies in size 18, gold ribbed hares ears in a variety of sizes, yellow humpies in sizes 12 and 14, damselfly nymphs, freshwater shrimp, or scuds, deer hair caddis in size 16 and Goddard caddis in size 14 and a good selection of foam-bodied winged ants.

The appearance of terrestrial ants on the surface of a lake isn’t frequent, but when it happens you don’t want to be caught without.

Henderson will never forget the time he stood on the shore of a secret lake in the Flat Tops and didn’t have an answer for the winged ants that were being blown onto the water by a breeze.

“I got caught without a termite and every fish in the lake was up,” Henderson recalled. “And there were big fish.”

Support Local Journalism

Support Local Journalism

Readers around Steamboat and Routt County make the Steamboat Pilot & Today’s work possible. Your financial contribution supports our efforts to deliver quality, locally relevant journalism.

Now more than ever, your support is critical to help us keep our community informed about the evolving coronavirus pandemic and the impact it is having locally. Every contribution, however large or small, will make a difference.

Each donation will be used exclusively for the development and creation of increased news coverage.


Start a dialogue, stay on topic and be civil.
If you don't follow the rules, your comment may be deleted.

User Legend: iconModerator iconTrusted User