Midges in Moving Water

Midges in Moving Water

First you have to notice fish are feeding on them.

  • By: David Hughes
  • Photography by: David Hughes
Midges in Moving Water

The most difficult part of solving any moving-water midge situation is figuring out when you’re in one. Midges are usually so small, and so often hatch at either dawn or dusk, that it’s often impossible to see them. You see trout rising, you suspect they’re not doing it as a hobby, but you can’t see anything they might be taking. When that happens, make midges your first thought because they might be dying in those rises.

On a recent early September float of Montana’s Bighorn River, Jim Schollmeyer and I enjoyed good fishing over a morning fleet of small blue-wing olives, then an afternoon emergence of black caddis. During both hatches we pestered pods of nice rainbows and browns working in the edge currents, from five to 15 feet from shore. We were satisfied with our day when it came time to reel up, move back to the boat and drift the remaining short distance before dark.

Just as we reached the boat and began putting away our gear, an extensive pod of trout began sipping something out in the shallow central currents, 100 feet from shore. As you know, a few extra trout don’t do any damage to an already bountiful experience. Naturally, we put off our plans and waded out there. Nothing was visible on the surface, and most of the rises were clearly just sub-surface, so we rigged quickly with tiny midge pupa patterns, suspending them on a couple feet of 6X beneath the black caddis dry flies.

The trout weren’t foolish, and we didn’t catch them on anything other than perfect dead drifts, right down their narrow feeding lanes. None of them took the dries, but those floating flies got tugged under often enough that we were able to determine that the pod was full of fat rainbows 16-to 20 inches long, several of which we were able to hold in our hands before the last light was gone. The single trout we sampled with a throat pump was full of black midge pupae, all size 20 and smaller. We finished out our float by the light of a rising moon.

River midges are typically tinier than most lake and pond midges, size 20 to 24. They go through three life stages: larvae, pupae and adult. The initial larvae are generally tucked tight into burrows in the bottom, or in rooted vegetation. Though it’s likely trout eat quite a few of them, they rarely do it selectively, and I’ve never found it necessary to imitate them. If you feel the need, they’re no more than simple tubes, and all you need is a hook wrapped with wire, thread or latex ribbing. In my experience, a size 18 to 22 Flashback Pheasant Tail, fixed as a trailer to a larger nymph, works as well as a midge larva pattern—often better—when trout are on the bottom and feeding on a variety of small insects and crustaceans, including midge larvae. But that won’t be true on every river, and a few simple larval patterns don’t take up much room in a fly box. Rig to fish them deep, and in dead-drift fashion.

Midge pupae are the most important stage of the insect, but as you can imagine—given their size and sub-surface presence—they’re extremely difficult to observe. Your major clue will be the presence of adults, if you’re able to see them. Even scant and scattered midges on the surface can be an indication of substantial trout feeding going on just below. You’ll see rises. They’ll appear to be made by fish rising to adults. But watch carefully: If no bubbles (which would indicate trout breaking the surface) are left in those rise-rings, those fish are feeding on pupae, and you need to match that stage to enjoy any success.

Matching those tiny pupae is less difficult than often supposed. They’re slender strings, with a bit of taper, and a bump at the head end where the formative thorax and wings are located. In their smallest sizes, which you’ll use most often on streams as opposed to stillwaters, such simple dressings as Gary Willmart’s Thread Midges, Bill Fitzsimmons’ Disco Midges, and Pat Dorsey’s Mercury Midges and Black Beauties are most effective. All of these patterns have a bit of brightness in the form of a wire rib, flash body or glass bead. In my experience, the flash speaks to trout of life, and enhances the effectiveness of tiny nymphs.

Colors can be various, but I’d never want to be on a stream without midge pupa dressings with black bodies. After black, blue might be a surprising good choice, while green, tan and red all have their moments of brilliance. For a much more thorough education in midge patterns than it’s possible to give here, do yourself a favor and read Ed Engle’s Tying Small Flies and companion book Fishing Small Flies, as well as Pat Dorsey’s Fly Fishing Tailwaters. Ed and Pat are from Colorado, which seems to be the seat of much of what we’ve learned about midge fishing in recent years.

My favorite rig for moving-water midge pupae includes a couple of tiny yarn indicators, about four to six inches apart on the leader, one of them black, the other white. In failing light, you’ll be able to see one or the other against river surfaces that are alternately dark or silvered with reflected light from the sky. I use a size 18 or 20 wire midge (in any color, on about two feet of 5X tippet) below the indicators. It’s mostly for weight, though I catch an occasional trout on it. At the end of another two feet of 6X tippet, I tie the size 20 to 24 pupal pattern. It usually works if it’s black, has a bit of brightness on it and—most important—is as small as the prevailing midges on the water I’m fishing.

In FR&R’s Summer 2011 issue, I wrote about fishing Sylvester Nemes’ Syl’s Midge pattern, swinging it slowly and a few inches deep when midge adults are on the surface. It’s another effective method for fishing midge pupae. Because you can always feel the thump of a take, it’s workable when there is not enough light left to see either a black or white strike indicator.

Though pupae are the most important stage of the midge, adults can be dominant, and can prompt trout to become selective to flies fished in or on the surface as opposed to sunken. Individual adults can be important on flats and in eddies, always on smooth water where trout have no trouble seeing and sipping them. I once floated and fished the Green River below Flaming Gorge Dam under the guidance of Reynolds Pomeroy, of Westbank Anglers. For some hours in early afternoon, trout worked lazily in big eddies, nipping at something it took us a long time to see. When we finally figured out it was midge adults—dark gray or black; we never did collect them—the trout became easy to solve with size 20 Griffith’s Gnats. The largest problem with those tiny flies was getting a drag-free drift in those conflicting currents, then seeing the fly on the water so we’d know when a trout accepted it. When we got it right, it worked.

I’ve gotten into trout feeding on clusters of midge adults often enough that I like to be prepared for them. It’s happened on the Cimarron in New Mexico, the Madison below Beartrap Canyon in Montana, the Yellowstone downstream from Livingston, and on the Crooked River in Oregon, too. Most often, in my narrow experience, it’s on a tailwater or in a freestone eddy, and it happens when the weather is somewhat bitter in either spring or fall.

You can find lots of flies specifically tied to imitate cluster midges, but I just add an extra hackle palmered over the body of a size 16 or 18 Adams or Light Cahill. Tied that way it floats high on its hackle points, and looks like the footprints on the water of a bunch of midge adults tap-dancing together across the surface. Most of the time it’s best fished dead-drift, over rising trout, but sometimes it helps to skate the fly a few inches, then let it drift free.

All the flies you need for moving-water midges fit into a single small fly box. I recommend you keep such a box tucked in some corner of your vest or pack, and begin honing your eyesight for signs of trout feeding on the tiny insects that call it into play.

Dave Hughes’ latest book is Pocketguide to Western Hatches, available at your favorite fly shop.