Life Cycle of a Midge and their importance on the Bighorn River

Life Cycle of a Midge and their importance on the Bighorn River

March 27, 2012 8:11 pm Published by 1 Comment

Assorted Midge Larva & Pupa

Midge Emergence on the Bighorn River

Midge species are extremely abundant on the Bighorn River where water temperatures remain fairly constant year round.  Midges have several broods throughout the year and have a very short life cycle, which makes midges on the Bighorn River widely abundant and  important year round. Because of their small size, trout have to eat numerous midges to obtain their necessary caloric intake each day.  Because of this fishing with midges tends to be the best in late winter and early spring when midges are the dominant food source available to trout. Throughout the course of the fishing day, fish can key in on any one of the three major stages of the midge life cycle: larva, pupa or adult/mating adults.

Midge Larva – Midge larva are small tube like organisms that have very pronounced segmentation throughout their bodies. Midge Larva can be found on the Bighorn River from size 14 – 28 with size 18 – 22 being the most important.  A midge larva is typically one size larger than the adults you see hovering above the surface.  Larva are present in colors cream, olive, yellow, black and red most often.

Midge Pupa – While the pupa stage is short for a midge, they are highly susceptible to trout as they ascend the water column to the surface.  Midge pupa are easily recognized by there pronounced head as the wing buds begin to show.  Because of their overall small size it can be difficult for midge pupa to break through the surface film to the water surface where they will crawl out of their larval shuck and become an adult.  Bighorn River trout key in on the susceptible pupa just below the surface film very frequently.  Anglers can take advantage of this by dropping a midge pupa imitation below a standard midge adult or midge cluster.  Drop the pupa about 10 – 12 inches behind your dry fly and expect the pupa to sink 3 – 4 inches below the surface right into the prime feeding zone.

Midge Adult

Midge Adult –Midge adults have two wings and sit relatively flush to the water. When a trout remains relatively stationary and is rising in rhythm with it’s snout visibly breaking the surface expect this fish to be feeding on single adults or adult clusters.  Either way exact drag free drifts made with the proper fly is key to catching these fish.  Presenting a fly in this case is a game of inches, with midges often being so abundant, don’t expect a fish to move from side to side much at all when single adults are on the water. Exact presentations are everything. In some cases midge adults have a propensity to skitter on the surface as well.  If you see fish slashing from side to side on the surface, the fish are most likely taking skittering midges.  While it is more difficult to determine an exact spot to present your fly with the fish moving so much, your presentation doesn’t have to be as perfect when the midges are skittering. Some movement with your fly is ok as long as it doesn’t create a large wake on the surface.

Midge fishing throughout the day can be both extremely frustrating and very rewarding.  Depending on the time of day and and the piece of water you are fishing, the fish can be keying in any stage or any part of each stage.  Not to mention the imitations needed to fool “midging” fish on the surface are tiny and difficult to see at best. One of the most frustrating parts of fishing the midge hatch on the Bighorn River is that just when you think you have a pattern down that the fish simply can’t refuse they do. Carry a wide variety of patterns in each stage, be patient, observe how the fish are reacting to and feeding on the emergence and make an exact imitation.  Best of luck on the water!

Midge Life Cycle

MIdge Life Cycle

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This post was written by Bighornangler

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