.......................  ......Fly Fishing Yellowstone National Park

08/12/09

Fly Fishing Yellowstone - Pale Evening Dun
Another little known mayfly that is present in some of the streams in Yellowstone
National Park is the Pale Evening Dun. They don't usually hatch in large
quantities but they are usually enough to get the trout's attention when they do
hatch.  At the time this mayfly hatches there are few other aquatic insects
hatching. Another reason you hear little about the mayfly is the crowds of
anglers have usually gone by the time it hatches.

The Pale Evening Dun is in the
Heptagenia group of mayflies. The Heptagenia
solitaria
species that exist in the West is usually called the Gray Fox. The other
species, mainly  the
elegantulata, is usually called the Pale Evening Dun. They
are found in many of the streams in the park and at all elevations. We have
found them in the Yellowstone River, Lewis River and Gardner Rivers but we
have not checked specifically for the mayflies in other streams. We feel certain
they exist in several others. They normally hatch starting about the middle of
August up until the middle of October but it depends on the elevation of the
stream and the weather. The hatch usually occurs late in the afternoon.

Pale Evening Dun Nymphs:
Heptagenia nymphs are clinger nymphs that for the most part are found in the
smaller streams with fast water. I say for the most part because they are also
found in the larger fast water streams such as the Yellowstone River. They
prefer pocket water with lots of runs and riffles.

By far the best time to fish an imitation of the nymph is just prior to the time they
hatch. Clinger nymphs stay hidden beneath and down between the small rocks
and cobble on the stream's bottom most of the time and are not available for the
trout to eat. When the hatch begins, the nymph will move out of their fast water
habit to nearby, slower moving water. This may be the pockets behind boulders
and rocks, pockets along the banks and other areas of slower water that is
adjacent to fast water runs and riffles.

Presentation:
You can fish our "Perfect Fly" Pale Evening Dun Nymph using some non-toxic
weight a few inches above it with or without an indicator. Use an up or up and
across presentation to the current seams between the fast and slow water of the
pockets and the edges of runs and riffles. We prefer to fish it without an
indicator so that we can keep in on or near the bottom.



























Copyright 2009 James Marsh
Our "Perfect Fly" Pale Evening Dun Nymph