The angler who examines the water's surface closely will find that what he originally thought were dimpling surface rises are in fact trout bulging the water as they take the pupae.
February 06, 2023
By Ed Engle
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This article originally appeared in the March 1980 issue of Fly Fisherman magazine. Click here for a PDF of the print version of "Fishing Between the Flakes."
It was a typical February afternoon for Colorado. The sky was clear, and a good bit of warmth radiated through the thinner atmosphere at 8,000 feet. The air temperature was in the forties. The South Platte was also in standard winter form–there were trout dimpling and bulging the surface, working a midge hatch that was in progress.
This stretch of the South Platte River was in the catch-and-release section of Cheeseman Canyon near Deckers, Colorado . The South Platte is well known for its midge hatches , and it displays several characteristics that many of the West's better winter midge-fishing streams and rivers hold in common. The influence of Cheeseman Dam on the South Platte is typical of other dammed western waters. Water released from the dam keeps the river open for three or four miles downstream during even the coldest winters.
Last winter, when the temperature dropped to 20 and 30 degrees below zero on some nights, the major channels stayed open. Ice that formed along the shore melted after a few days of sunshine; yet, downstream at Deckers the river froze over completely.
Many anglers believe that one reason the South Platte is so rich in midges is that the larvae are washed down into the river from the silt deposits that build up behind the dam. Midges–variously referred to as no-see-ums, gnats, snowflies and punkies–occupy many genera in the order of Diptera . Probably the most important single genus in the West is Chironomus . The most characteristic features of the adult Chironomidae are the humped back and small head. Adults range in size from 4mm to about 15mm and range in color from olive and brown in highly oxygenated and alkaline waters, to bright purple in more acid and less oxygenated waters.
Chironomidae are found in most aquatic environments. Depending on weather conditions, they can hatch at any time of year in tremendous numbers. Trout will feed heavily during these hatches.
Fishermen new to midge fishing tend to reach immediately for their dry-fly boxes when they see what appear to be the dimpling rises of trout. Although some adults are taken during a Chironomus hatch, the majority of feeding is concentrated in the surface film on emerging pupae. These pupae resemble worms with weblike thoracic gills. They rise toward the surface and spend a brief time in the surface film as the pupal shuck is split. At this time they are most vulnerable to winter trout that are trying to eke out a profitable metabolic trade-off by feeding in the cold water. The angler who examines the water's surface closely will find that what he originally thought were dimpling surface rises are in fact trout bulging the water as they take the pupae.
Midge pupae imitations will catch the most fish for the winter midge fisherman , and they should be tied on hooks #20 to #24. Go smaller if it appears necessary. I have found olive-dyed rabbit is the most effective body dubbing in the rivers of the West. Black-dyed rabbit is almost as good. The body dubbing should be thin in order to represent the wormlike appearance of the pupal abdomen. The most important aspects of effective pupae imitations are the gills. Although you will catch some fish with a dark-muskrat dubbed head, it doesn't really imitate any gill action in the water. I have found that a dark-colored, downlike material, such as the webbing of a feather–or better yet, the actual down feather found on a partridge–is excellent. The down should be wrapped like a hackle and tied off. If webbing is used, it is best to wrap it around the hook several times, then tie it off and pick the fibers out with a dubbing needle. That is all an effective pupa imitation needs: a thin body and soft web hackle. In fact, I've found that if I rib an imitation with fine gold wire it is generally less effective.
A very effective pupa pattern on the South Platte is called the RS2 . Its body is dubbed with Australian opossum, and the dark webbing found at the base of a Furnace-colored saddle hackle is used for the gills. The translucent properties of the opossum fur seem to account for the fly's effectiveness.
The best way to fish the pupa is to cast it a few inches upstream from a bulge and dead-drift it in the surface film toward the fish. Sometimes it is effective to cast the fly right at the bulge because the trout establish feeding lanes during peak hatching times, and often they will not even move a few inches to take an imitation. Since rivers are usually very low during the winter season, a 7X or 8X tippet is required. A good tactic for low, winter water is to work the trout that are rising where a chute fans out into a pool. There is usually good midge activity in these areas, and the broken water will help disguise the tippet.
Detecting the strike to a pupa imitation can be difficult. If you are casting to bulging or dimpling activity you can in some cases see surface movement in the vicinity of the fly and set the hook. It is best to watch the leader or end of the fly line, and if either hesitates or makes any unusual motions, set the hook. Large trout have a way of taking a fly in a delicate manner.
One of the most frustrating aspects of midging for the beginner is the frequency of break-offs. With the delicate equipment necessary for midging some break offs are unavoidable, but special tactics can eliminate many. Striking the fish too hard is a common mistake. When the trout takes, you should just tighten the line. If you are in the habit of striking more fiercely, you might try making a ring with the thumb and forefinger of your line hand, and when you strike the fish, let the line run through this "ring." This causes enough friction to set the hook but not enough to break the tippet. Another aid is to use very long tippets. A 25- or 30-inch tippet may pile up a little when you cast, but it also adds quite a bit more stretch to the system when you hook a big fish. A short tippet has less elasticity than a long one, and will break more easily under stress.
When playing the fish it is usually best to hold the rod tip high. There are cases with large trout where it may be necessary to drop the tip and throw the fish line on a particularly strong run. If you do this, it is important to get some tension on the fish when he stops. The most important time when playing a fish on a light tippet is the first run. You must resist the urge to horse the fish in any way on this first run. I recommend the use of a landing net, since it enables you to land and release fish faster, thereby increasing the fish's chance of survival and decreasing your chances of making mistakes.
As you become more adept at midging you will notice that a midge hatch presents many subtle diversions that offer opportunities for an array of tactics. Dry flies in #20 to #28 can be very effective under certain conditions. Generally any quill-bodied fly is best. I carry a selection of light to dark quill-bodied flies, hackled with ginger, grizzly and blue dun. However, it is difficult to see these small flies on the water, and it sometimes works to position yourself as close as possible to the feeding fish and dap the fly on the surface. Dry flies are also effective in pockets of still water where fish are working steadily and your visibility is good. Brown trout will rise much more freely to the small dries than will any other species. At times, if activity toward a pupa imitation declines, but the fish are still rising, a dry fly is the answer. Presentation must be delicate and precise.
This article originally appeared in the March 1980 issue of Fly Fisherman. When the air is cold, there will be a high incidence of stillborn pupae and live pupae that get stuck in the pupal sac. At such times the trout often become quite selective toward these "easy-to-get" targets. Larger trout will often be totally selective to these forms. My greatest success under these conditions has been with floating nymphs.
My patterns for the South Platte are tied with olive bodies, black ostrich wingcases and ginger hackle clipped top and bottom. I wondered why this pattern was more successful for me than the Swisher-Richards stillborn patterns that seem to be more accurate imitations. Upon close examination of the water I fish in the South Platte, I found that the incidence of stillborns is not very high, but that quite a few nymphs do get stuck in the pupal sac. Almost invariably the midge is caught by the abdomen with its wings splayed, spinner fashion, on the surface. Apparently the floating nymph with its hackle-trimmed top and bottom imitates this condition accurately. The key to these stillborn situations is to get out on the water and to observe the actual condition of the pupae that the fish are taking. Midges are plentiful in most watersheds and certainly deserve the attention of fly fishermen. Although pat terns that imitate these midges are small, and many of the techniques are difficult, studying these hatches can extend your fly-fishing season through the winter months. Midge fishing requires patience and skill, but any trout is a trophy when landed on a fine 8X tippet and a #24 fly.
One more thing: Pack some matches and a change of dry clothes on winter-midging trips . It's not hard to end up in the river when you're chasing a 20-inch rainbow down the river.
Ed Engle lives in Manitou Springs, Colorado. This is his first contribution to FFM.
