Fly Fisherman Throwback: Rene Harrop's "Emergers: The Other Stage"

Not quite fully developed duns, but certainly no longer nymphs, they are an important factor in the game of chess played between angler and trout.

May 24, 2022 By Rene Harrop

Editor's note: Flyfisherman.com will periodically be posting articles written and published before the Internet, from the Fly Fisherman magazine print archives. The wit and wisdom from legendary fly-fishing writers like Ernest Schwiebert, Gary LaFontaine, Lefty Kreh, Robert Traver, Al Caucci & Bob Nastasi, Vince Marinaro, Doug Swisher & Carl Richards, Nick Lyons, and many more deserve a second life. These articles are reprinted here exactly as published in their day and may contain information, philosophies, or language that reveals a different time and age. This should be used for historical purposes only.

This article originally appeared in the May-June 1982 issue of Fly Fisherman magazine. Click here for a PDF of the print version of "Emergers: The Other Stage."

Over the years there have been many changes in American fly fishing, but casting a floating artificial over a visibly feeding trout remains one of the sport's most popular pursuits. There are many insects, both aquatic and terrestrial, that will bring a trout to the surface, but if we were to choose·one symbol of dry-fly fishing it would undoubtedly be the mayfly.

There are numerous quality trout streams throughout the country but there are none better than those in and around Yellowstone National Park. The multitude of slow-moving, spring-fed streams are renowned for their difficult currents, selective trout and tremendous mayfly hatches. The problems these complexities pose to the angler are many, but none is more perplexing than the dilemma of deciding which fly to use during a mayfly hatch.

Most serious fly fishermen know that mayflies exist in three separate life stages, each possessing its own distinct characteristics. The nymph lives beneath the surface and in many instances bears little resemblance to the other two stages. The dun occurs when the nymph rises to the surface, sheds its nymphal skin and is transformed into the familiar upright winged insect that we associate with the hatch. The spinner, which resembles the dun in many ways, can be distinguished by its long tail and transparent wings that lie outstretched when the fly is on the water. There is a period, however, when the mayfly's appearance and behavior do not conform to any of these stages.

The remarkable transition from the often grotesque nymph to the delicate-winged dun is known as the emergence. But there is an interim period when the insect is no longer a nymph, nor yet a fully developed dun. While it couldn't actually be classified as a true life stage, there has been a tendency among anglers to refer to the mayfly at this stage as "The Emerger." Regardless of whether the term is technically accurate, emerging mayflies are an important factor in the game of chess played between angler and trout.

There is a lesson to be learned in virtually every fishing experience and, although I failed to realize it at the time, I had my first lesson in the value of the emerger on a memorable day many years ago.

The rain had stopped but the rugged peaks of the Absaroka Range were still obscured by a cloak of dark clouds. A blanket of mist lay over the valley they call Paradise. I felt a twinge of anticipation as I pulled my car down past the old red barn and parked among the tall cottonwoods that guard one of Montana's finest spring creeks.

Swallows dipping over the surface signaled that something was already happening on the little stream and I hurried into my waders and vest. With fingers trembling in familiar excitement, I strung the eightfoot rod and replaced a wind-knotted tippet on my ten-foot leader. Forcing myself to ignore the scattered rises that had already begun to appear, I stepped over the rickety stile and headed upstream.

The pool at the old sheep corral is a classic. It was there that I felt I would find the heaviest insect activity and the largest trout. Two enormous cottonwood logs, strategically placed in an open V at the pool's head, accelerate an otherwise slow current and provide a hiding place for big trout. The faster current keeps the pool relatively silt- and weed-free, making it ideal habitat for a host of aquatic insects. Often, as many as twenty or thirty good fish work this pool during a mayfly hatch.

Several fish were already showing as I stood in the tall grass at the tail of the pool. Most of the trout seemed to be moving in search of pale mayflies appearing in gradually increasing numbers. One fish, however, was feeding with some degree of regularity. As he fed tight against a bank of exposed weeds, his rises were almost imperceptible in the poor light. He rose a half-dozen times in the space of a few minutes and I decided to try for him. I eased into the water from a sitting position on the bank to begin my stalk. Thirty feet away, the trout was well within casting range but a ten- or fifteen-foot reduction in that distance would improve my chances for a good presentation. Crouching low, I moved cautiously forward until I reached the right position. I paused briefly to pluck a floating dun from the water. It was a medium-size mayfly with pale-gray wings. Sitting in the palm of my hand, the fly's body looked grayish olive. But a trout sees the dun's underside, and when I turned the fly over, it showed yellow. I selected a #16 fly with light-gray wings and a dirtyyellow body of dubbed fur. Tied without hackle, it was a good match for the natural. I confidently clinched it to the 5X tippet and turned my attention to the trout.

A trout chooses its feeding position for a reason, and in this case the reason was obvious. The current, breaking around a partially exposed rock, created a natural funnel that collected the drifting duns and delivered them to the waiting trout. It was a simple matter of casting the fly into the food line with enough slack to prevent drag.

The next hour convinced me this would be one of those rare days when everything goes right. The water was carpeted with mayflies and the pool was alive with feeding trout. Without moving from my original position, I took three more decent fish from against the weed bank. Then, working my way up the pool, I landed a rainbow that measured nearly twenty inches. It was in a tough spot between two rocks but took my dry on the first pass. I was heady with success and about to zero in on another good fish when suddenly my attention was diverted upstream.

There was nothing subtle about the way the fish fed. Ranging back and forth across the pool head, its massive bulk pushed wakes in the shallow water as it assaulted the hatch. A brown trout of enormous proportions for so small a stream, it dwarfed the pool's other inhabitants.

I studied the situation carefully. If I tried to approach from below I would spook other trout that would put it down before I could reach good casting range. The big logs at the head of the pool made it impractical to approach from above. There seemed no other alternative but to approach it from the side. I carefully made my way toward the far bank.

Keeping low and causing as little disturbance as possible, I crept upstream until I reached a point across and slightly above it. Then, easing to my knees, I worked out into the current until we were separated by less than twenty feet.

The big trout moved constantly, working diagonally across the current one way, then dropping back a few feet and working back the other way at a similar angle. It would be a question of timing the delivery to put the fly in the trout's path as it made its circuit. It would be difficult, but I was casting well and was confident I could pull it off. The heavy cloud cover would eliminate any problem with rod or line shadow. I was relaxed as I prepared for the first cast.

So closely spaced were the big trout's rises that it seemed to be up more than down. I waited until it fed away and laid the fly two feet ahead and a foot above the broad, blunt snout. The presentation looked good and I tensed as trout and fly moved together. I was only slightly disappointed when the trout rose just inches early and I watched as my fly washed over its head.

"Next time," I muttered as I waited for the fly to drift well downstream before picking it up for the next cast. Twenty casts later I was still muttering "next time." While most of the time the fly arrived either too early or too late, there were several times when I was convinced the presentation was perfect. Meanwhile the trout continued its methodical feeding. "Perhaps the fly is too large," I thought and quickly replaced the #16 with a similar pattern one size smaller. Time after time I sent the little dry fly drifting past the huge trout's nose, but each drift brought a refusal. I switched to a #14. Still no interest!

My right hand and wrist ached from a hundred fruitless casts. Reeling up the line, I shifted the rod to my left hand and studied the water while waiting for circulation to return to my numb fingers.

"It's possible," I thought, "that it's taking something else." But my examination turned up nothing other than the same pale mayflies that had been coming off for the past two hours.

It was obvious the big fish was surface feeding. I had eliminated nymphs as a possibility much earlier, but now I was desperate. I had worked the fish for over an hour and knew something must be done soon or I would lose both the hatch and the fish. I reached for my box of mayfly nymphs.

The confidence I had begun with was gone as I knotted on an olive-brown Ephemerella nymph. The big brown's red flank spots showed faintly and I could see its gills working as it fed back and forth across the surface. Once more I extended the line, dropping the nymph gently above my opponent. "It's too long," I thought. But the brown didn't agree. In a flash it charged, engulfing the nymph before it could sink. So sudden and unexpected was the take that it caught me totally off guard, and I felt the trout's weight only briefly before the tippet snapped and we parted company as quickly as we had come together.

The barb's sting seemed to enrage the fish. I'd had the feeling for nearly an hour that it knew I was there and also what I was trying to do. It had seemed to taunt me, daring me to beat it. Now it charged about the pool like a demon, scattering its downstream subordinates in all directions. Gradually it regained its composure and I watched dejectedly as it cruised slowly upstream and out of sight.

I'd been casting from a kneeling position throughout the encounter and my legs were weak and wobbly as I made my way to the big log that angled out into the current. I slumped wearily down on the weathered trunk. A fair-size trout resumed feeding on the far side of the pool, but I had neither the energy nor the desire to fish for it. My duel with the big brown had taken its toll and I wound in the line and flyless leader.

As I headed for the car, a late-afternoon sun burned through rapidly dissipating clouds. I paused on the trail for a final look at the pool. The Absaroka's rocky crags, bathed in fluorescent shades of pink and orange, loomed high above the valley floor. I had lost the big trout but it had still been a good day. I knew I would be back.

It was a fluke. The big brown had taken my nymph while on the surface and I made no attempt at the time to rationalize his behavior. Not until later, when I'd had the opportunity to observe closely the emergence process of large mayflies raised in an aquarium, did I realize the full significance of the experience. Perhaps there was an explanation for the trout's unexpected response to my nymph.

I observed that the freshly emerged flies, with their wings rolled tightly against the top of the thorax, still maintained the overall shape of the nymph. The flies remained in rather than on the surface, while their wings began to unfold gradually into an upright position. It was easy to see how a mayfly in this helpless situation would be an attractive target for a foraging trout. It was also obvious that a conventional dry fly would not adequately represent the undeveloped dun.

I knew there were patterns called emergers but those I had seen were tied like wet flies and were designed to be fished beneath the surface. Concentrating on the nymph-like configuration of the newly emerged insect, I began experimenting with various materials in an effort to create an artificial that would duplicate this little-understood stage of emergence. Flotation and visibility were of foremost concern, but durability and realism were important as well. Eventually, through trial and error. I developed a pattern that filled my requirements. The "floating nymph" I tied was primarily of synthetic dubbing. It floated well and proved reasonably easy to see if fished on a relatively short line. It was durable and the fish took it well. Several more patterns followed as I became increasingly convinced that emergers are in many instances the answer when a trout is feeding selectively on the surface.

My wife is a highly accomplished fly tier and a skilled and observant angler. Bonnie loves spring creeks and her passion for these special streams, if anything, exceeds my own. She has a mind of her own, as indicated by the many original patterns she ties for her own use. A pattern we both have found especially effective is the Half-and-Half Emerger, which has the characteristics of both a wet fly and a dry fly. The rear portion is designed to sink while the front portion is tied with water-resistant materials and floats. To fish this fly I use a silicone, paste floatant to dress only the legs, wings and thorax. I leave the tail and abdomen untreated. When presented to a trout, the fly assumes a tilted attitude in the water. The sparse tail, with the slight weight provided by ribbing the abdomen with fine gold wire, allows the fly's rear portion to penetrate the surface while the front is supported on the surface by buoyant duck-quill wing stubs and silicone.

The famed Green Drake hatch that draws thousands of expectant anglers to the Henrys Fork each·year is supposed to cause trout there to become suicidal idiots. During this hatch, bushy hairwing flies will take fish in fast riffle water and there are effective extended-body dun imitations. However, most of the fly-only water on the Henrys Fork is slow-moving with a smooth, even surface. Trout can be just as discerning when feeding on these oversized Ephemerellas as they are when feeding on smaller mayflies. An emerger pattern that exhibits the same bright coloration as the natural has proved the most effective Green Drake imitation for these conditions. The fly resembles soft hackle wet flies of recent interest, but I dress the fly with floatant and fish it on the surface.

Doug Swisher and Carl Richards have described a pattern they call the "stillborn dun" that imitates an emerging mayfly with the nymphal skin still attached. The term stillborn suggests the insect is dead. But, while mortality of this nature undoubtedly exists, it's unlikely that it occurs in sufficient numbers to cause a trout to feed exclusively on them. Emerging mayflies often experience difficulty in freeing themselves and they remain in this partially emerged state for several seconds. The Swisher-Richards pattern is an effective imitation of a mayfly in this predicament. It's a worthwhile fly to keep on hand.

The extent to which a trout responds to the emerger stage is determined by the length of time the emerger is available–the time it takes the mayfly to free itself from the nymphal skin, dry its wings and rise to ride lightly on the surface as a fully developed dun. Under ideal conditions, the emerger is transformed into a dun almost instantly. Drying of wings and warming of muscles is accelerated by bright sunshine and warm air temperatures. Under these conditions, a dun imitation with a high profile can produce as well as or better than a low-floating emerger. Damp, overcast conditions inhibit emergence, however, and the insect may spend a long time drifting helplessly. Air temperature lower than water temperature–during evening or early-morning hours, for instance–can create the same conditions. Emerger patterns fished at these times are more likely to interest surface-feeding trout than a dun pattern.

Feeding position is another significant factor in determining whether a trout is taking duns or emergers during a mayfly hatch. Mayflies often emerge more profusely from the riffled waters at the heads of pools than from slower water downstream. A surface-feeding trout in these areas of intense hatching activity will often take emerging insects almost exclusively. Trout feeding farther downstream, however, may find the drifting duns an easier food source.

Half-and-Half Emerger

HOOK: Mustad 94840, #14-#22 (round bend. turned-down eye, extra fine wire).
THREAD: 6/0 prewaxed nylon.
TAIL: 3 or 4 wood duck fibers.
BODY: Fur dubbing to match the natural insect.
RIBBING: Fine gold wire.
WINGS: 1 or 2 pairs of duck quill segments tied short and on the sides of the fly.
LEGS: 5 or 6 brown partridge fibers.
THORAX: Same as body.

Stillborn Dun

HOOK: Mustad 94840 (round bend, turned-down eye, extra fine wire).
THREAD: 6/0 prewaxed nylon.
NYMPHAL SHUCK: Webby hen hackle tip or clump of marabou.
BODY: Fur dubbing to match the natural insect.
HACKLE: 2 or 3 turns of stiff cock hackle tied in the middle of the body.
COVERT (wings): Duck or goose quill segment tied over back of fly.

Green Drake Emerger

HOOK: Mustad 94842, #10-#12, (round bend. turned-up eye, extra fine wire).
THREAD: 6/0 prewaxed nylon.
TAIL: 3 or 4 wood duck fibers.
BODY: Goose quill dyed bright yellow.
THORAX: Bright-olive seal fur.
HACKLE: 4 turns of soft grizzly hackle dyed bright yellow and two turns of soft black hackle.

Floating Nymph

HOOK: Mustad, 94833 (round bend, turned-down eye, 3 extra fine wire).
BODY: Synthetic fur dubbing to match natural in sect.
RIB: 2/0 monocord.
WING CLUMP: Synthetic fur dubbing to match the wings of the natural insect.
THORAX: Same as body.
LEGS: 3 or 4 brown partridge fibers or cock hackle tied on the sides of the fly.

Some trout–often battle-scarred, large veterans with sharply honed survival instincts–are extremely reluctant to feed in open water. Such trout are normally passive surface feeders that select sheltered locations, usually outside the main current flow, and let the current deliver their meals. Tucked tightly against the bank or along the edges of exposed weeds, such trout rise so subtly as to be almost undetectable. Large rocks or logs also provide good cover for such fish and should not be overlooked. A concealed trout typically focuses attention on drift lines created by deflected currents, spots where mayfly duns are collected and delivered to its position. A well-presented dun imitation is often the best fly choice, but I have experienced times when a winged emerger pattern worked well.

Mayfly emergers are extremely vulnerable, and the traumatic experience of sudden transformation from underwater. nymph to winged, air-breathing dun must stun the insect momentarily. New muscles must be flexed and wings dried before the helpless insect can fly to safety. There is little doubt that trout relate vulnerability to availability, at such times know an emerger is less likely to escape than a dun, and feed accordingly. Spring-creek trout are often observed moving about as they feed. These hunting fish have probably located a quarry long before it reaches the surface. Although the mayfly is still a nymph when the trout makes his decision, it has often already emerged before he actually takes it.

It is possible to tie emerger artificials that imitate both the appearance and the behavior of the natural. I've always felt that spinners are effective because they can be tied and fished so they perfectly represent the real thing. When on the water, these dead and dying spent wings are in full contact with the surface. On the other hand, nature has blessed the mayfly dun with perfect balance. As a rule, the tail and abdomen are held well above the water with only the legs and the underside of the thorax touching the surface. I have seen many patterns that imitate the appearance of a dun remarkably well, but to my knowledge there isn't one that accurately imitates the way a mayfly dun rides the surface. Contrary to what many anglers have been led to believe, a conventional dry fly tied with the stiffest hackle and the lightest material available will not ride the surface on the tips of its hackle and tail. A good emerger pattern, however, is meant to float low in the surface, which corresponds perfectly with the position of a natural.

The emerger patterns I have described are dry flies and should be fished accordingly. I've found them most effective when delivered to a trout dragfree with the fly preceding the leader.

Emergers are not always the answer in dealing with the complexities of a mayfly hatch but if a surface-feeding trout is ignoring your best dun imitations there is a good chance that an emerger will do the trick.

Rene Harrop has lived on the Henrys Fork of the Snake River all his life and has fished his home waters for more than 25 years.