BIGHORN RIVER MIDGE FISHING
Midges (diptera)
Duration: Year Round Most prevalent February – May
Size: 18 – 22
Colors: Black, Brown, Olive, Cream
As with every tailwater, midges are extremely plentiful on the Bighorn River. In the winter and early spring, while water temperatures are still too cold for mayfly hatches, midges are the predominant insect emergence. This emergence is significant for both the angler and fish alike, as it is the trout’s main food supply at this time. The abundance of larva and pupa in the Bighorn makes it easy for the trout to feed while expending very little energy when their metabolism is at its lowest point.
Good Midge Fishing will start in February and often last well into May. As water temperatures warm up from February to May the window each day in which midge emergences occur will widen. Productive nymph fishing with larva and pupa imitations can be had any time of the day. Typically surface action will start at 10am with single adults and emergers. Fishing midge clusters will start getting good in the early afternoon. An overlooked time in the spring, during midge emergences, is the last hour before dark. In February you may only get a two-hour window of good surface action, where in April you could get a window that lasts nearly all day. Good fishing with adult midge clusters only occurs once the hatches become dense enough. Midge fishing is at its best on the upper 3 miles, where these hatches are the most prolific, but midge patterns fish very well all the way down to Bighorn Access.
Midges go through a complete metamorphosis, which includes a larva, pupa and adult stage. While midge larva are effective fished along the bottom, midge pupa, as they ascend to the surface, are most vulnerable to the trout. Because of cold water temperatures and the midge pupa’s minute size, it takes a long time for the pupa to reach the surface. Once it almost reaches the surface, the pupa is further impeded by the surface film. Here midge pupa collect and trout gorge on these easy pickings.
A midge pupa imitation fished on a greased leader or trailed behind a midge adult dry fly is a deadly tactic during the midge hatch. Having a stable of fly patterns that sit just below or flush to the film is very important for success in the spring. A standard black midge pupa dropped a short distance off of a midge cluster, or a CDC Transitional Midge, are two of the best patterns for targeting these fish feeding in the surface film. Anglers sometimes find this kind of fishing very frustrating, because these imitations are nearly impossible to see. Anglers should carry a few hi-vis point flies that are easy for them to pick up quickly and see on the water. When fishing small dries on the Bighorn, such as midges, I find that anglers don’t take enough time during fishing to manicure their flies, by applying dry floatant. When I am guiding a client, if I can’t see their fly, with my highly trained eyes, there is usually no way that they can see it either. You should be incredibly diligent about drying your small dries, even if it means dusting them with floatant every two drifts.
Throughout the winter and early spring, midge adults can be found in the air during the warmest part of the day. Look for fish to key in on single midge adults in the late morning and focus on mating clusters in the afternoons and evenings. The mating clusters are highly susceptible to the trout and trout feed readily on them when they are present. A standard Griffith’s Gnat or Twilight Midge are perfect representations of the natural clusters. The clusters can get so large on the Bighorn that you will want to carry cluster imitations all the way up to a size 14!
As we move further into spring and the water begins to warm, look for Blue Winged Olives (Baetis) to hatch simultaneously with midges. While the grey winged BWOs, with a sailboat silhouette, will be easily noticed on the surface of the water, the fish may very well be eating midge adults or clusters. Fishing a BWO dry up front with a midge cluster trailed 16” to 18” behind is a great way to approach rising fish in the spring.
Success with fishing midges below the surface comes down to selecting an imitation that is the right size and color. Midges can be present in a wide variety of colors and sizes throughout the year. Larva and pupa may be present in black, brown, olive, cream and red. It is important to carry variations of each. Bighorn trout readily key into a certain color midge–be it hourly, daily or weekly. In the spring, I find the use of a stomach pump to be invaluable at determining which color larva or pupa the fish are keying in on. You will often get midge larva from their stomach that are still moving. You should pay attention to the size and color of these especially.
As an angler, it is also crucial to be able to differentiate a midge larva from a midge pupa. The larva simply look like tiny segmented tube-like worms. When these larva transform into pupa they grow clear, or white, wing buds that are easily identified by anglers. Being able to recognize this will allow you to appropriately identify the naturals you have collected and select a proper imitation from your fly box.
