, midges are the predominant food source, making up as much as 50 percent of a trout's diet. Unlike many other aquatic insects, midges can complete an entire life cycle during the winter months. Many species can undergo a complete life cycle—egg to adult—in just a few weeks.
The most widespread group of midges are chironomids, members of the Chironomidae family. While the majority of midges are small, they are hugely important. What they lack in size is offset by their massive populations, making them a viable food source for trout 365 days a year.
I have found that midge fishing is really only as tough and complex as you make it. Your success with midges begins by being able to recognize and understand their life cycles, coupled with choosing the appropriate artificial flies to imitate the various stages of their lives. While there are about 1,000 midge species, and their identification is difficult at best, keep things simple. Don't outthink yourself—as far as you and I are concerned, a midge is a midge. It's hard to go wrong with the size, shape, and color formula when narrowing down your fly selection.
Larvae. Midge larvae look like little worms. Identifying features include: a slender, slightly curved, uniform abdomen with visible segmentation and a pair of prolegs. Their heads are small, but noticeable, and easy to imitate with a few wraps of tying thread. Midge larvae are found in a wide range of colors including blood red, pale olive, gray, brown, and black. Most midge larvae are between 3 and 10 millimeters—about the length of a size 16 to 22 long-shank hook. Many anglers overlook fishing larvae imitations, which can be a huge mistake.
Larvae live in the substrate of our trout streams. They attach themselves to rocks, burrow in mud, silt, and other debris, or cling to aquatic foliage.
According to Leonard C. Ferrington, Jr., a professor at the Department of Entomology at the University of Minnesota, "Midge larval densities depend on month of year, productivity of stream, and kinds of stream-bottom substrates. Typical densities, however, may range from 800 to 2,000 larvae per square meter."
Larvae in areas with lower oxygen levels are often bright red because they contain hemoglobin, an oxygen-carrying metalloprotein that allows them to survive in silty environments with little or no oxygen. Anglers often refer to the red wormlike larvae as blood worms or blood midges.
Larvae imitations are productive year-round because they have a tendency to drift continuously in the current, a phenomenon referred to as constant drift. A steady supply of drifting midge larvae is especially important for opportunistic trout when other aquatic insects are inactive. A sudden increase in stream flow can also knock loose larvae, creating small feeding frenzies and the perfect opportunity to fish larvae patterns.
Pupae. When midge larvae reach maturity, they develop into pupae. Pupae are shorter and stockier than the slender larvae. The thorax is swollen, containing the wingpads, legs, and gills, with highly visible segmentation throughout the abdomen.
I tie my pupae imitations in sizes 20 to 26, in a wide range of colors—black, brown, dark olive, and gray.
Prior to emerging, pupae become fidgety, moving up and down in the water column several times before the adult finally breaks free from the pupal sheath and pushes its way through the meniscus.
A layer of highly reflective trapped gases produces a mirrorlike bubble in the thorax and a translucent abdomen. Size, shape, color, plus a "dash of flash" are important when tying and fishing pupae imitations. Silver-lined glass beads, Krystal Flash, Medallion Sheeting, Gliss N Glow, and Mylar tinsel are all popular and effective in midge designs because they imitate this reflectivity.
Pupae patterns are most effective when naturals are ascending to the water's surface or when they are hanging in a C shape, suspended just below the surface film. The emerging process is slow, giving trout ample opportunity to capitalize on an effortless meal. Concentrations of wiggling, rising pupae draw the attention of nearby trout, producing a steady feeding rhythm.
Adults. Adults emerge by breaking through the surface film, pulling themselves out of their suspended pupal sheaths by using their legs to push on the surface tension. During this phase, the emerging midges appear to be twice as long as the pupae because of the trailing shucks attached to the adult bodies.
Trout may key in on different phases of the emergence, and midges can look astonishingly different from one phase to the next. At first, the emerging insect appears as a significant hump on the back of a floating pupa, and patterns like the Medallion Midge are a perfect match.
As the wings struggle to pull free from the pupa, the trailing shuck can be a significant trigger. Some adults never complete the emerging process—they remain trapped within their pupal sheath. Stuck in the Shuck or trailing shuck patterns are excellent imitations for these struggling cripples. Most imitations are black or cream with a few strands of orange, amber, or cream Z-Lon or Darlon protruding from the hook shank to represent the trailing shuck.
When a midge's wings are first fully extended (upward), the silhouette can appear almost mayflylike, and a small Parachute Adams or Cannon's Suspender Midge are not only effective, but easy to spot on the water.
After complete emergence, the adults sit on the water long enough to dry their wings and prepare for flight. Downwing imitations like Matt's Midge fool trout that are selectively feeding on midges resting in preparation to leave the water's surface. On many occasions, I have experienced trout that refuse anything but downwing-style artificials.
It is not uncommon to see clusters of midges on the water's surface after strong hatches—especially during the winter and early spring. I have observed many instances where a group of midges cling onto one another, twisting and turning on the surface. Trout feed confidently and voraciously when these clusters form. Griffith's Gnats (#14-18), Cannon's Snowshoe Midge Clusters (#20), or Dubas's Midge Clusters (#15-17) are effective.
Fishing larvae requires no sophisticated tactics. Most anglers dredge larvae patterns close to the substrate where the greatest concentrations are found. I have had my best success with pale olive and red larvae imitations. Effective patterns include size 18 to 22 Barr's Pure Midge Larvae, Mercury Midges, Mercury Blood Midges, and Rojo Midges.
I fish my larvae as attractors in a conventional, two-fly nymphing rig. A good rule of thumb is to keep your strike indicator adjusted to 11/2 to 2 times the depth of the water—measured from your split-shot or other weight. I space my flies 14 to 16 inches apart, using a midge pupa as the top fly because a pupa should naturally drift higher in the water column than a larva.
When a midge hatch becomes evident and trout begin intercepting midge pupae higher in the water, I snip off my larva and fish two pupae. This decision is based on trout switching from opportunistic to selective feeding. My favorite pupae imitations include Mercury Black Beauties, Top Secret Midges, Medallion Midges, and Jujubee Midges (#20-26).
Fishing pupae requires more finesse and skill than dredging larvae. Concentrate your efforts in transitional zones (mid-channel shelves or gravel bars) that funnel into deeper water. Locate pods of feeding fish as opposed to targeting a single fish.
Getting your flies in the correct feeding zone can make or break your success. It is entirely possible to use too much weight during the height of a midge hatch. The speed of the current, and the depth of the fish, help determine the amount of weight you'll need. In most cases, a #4 or #6 split-shot is sufficient.
The "takes" are subtle, therefore I prefer a sparse yarn strike indicator because they are the most sensitive. In many cases the strike is only a small dimple around the indicator.
The best hatches occur during the low-light hours. Trout keying on emergers or adults are generally suspended just below the surface, not hugging the bottom. During the initial phases of the hatch, trout may eat both hanging pupae and adults.
Pupae should be fished in the surface film. Emergers should be fished half in and half out of the meniscus.
The greased-leader technique works well when trying to fool trout that are keying on pupae just below the surface. Apply silicone floatant to the entire leader excluding the last 12 inches closest to the fly. The ungreased section allows the pupa to sit just below the surface, precisely where you would expect to find emerging pupae.
Another effective method is to fish a dry-dropper rig, suspending a tungsten Flashback Black Beauty off a dry fly, or emerger. This is especially effective in skinny water where traditional nymphing rigs tend to spook trout or get hung up on the bottom.
This is a great play in anticipation of things to come, as once the trout turn their attention to adult midges, you can simply cut off the dropper and focus solely on dry-fly fishing. My observation leads me to believe that once trout commit to feeding on adults