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

06/21/09


Fly Fishing Yellowstone - Western Green Drake

Not many anglers are aware that there are two different species of Western
Green Drakes. Both the
Drunella dodsi and the Drunella grandis are commonly
called Western Green Drakes. The reason is that both species are very similar
in looks and behavior.  In fact the duns look so much alike it would be almost
impossible to distinguish between them. The nymphs vary a little but not much.
They are so close it actually takes a microscope to determine the difference.
This of course means that one imitation of the two different species is all that is
needed. There are difference in the types of water they are most commonly
found in and the times of the year they hatch. Even so, both species are found
in some of the same streams although usually different locations in the stream.  

Anglers think of fishing for trout using only the dun imitation. You rarely see
anyone fishing the nymphs, emerger imitations, or imitations of the spinners.
Facts are trout can be taken on imitations of all stages of the Green Drake
mayflies life. Sometimes, the emergers are much more effective than the dun. At
times the spinner fall can be very productive. Fishing imitations of the nymphs
just prior to the hatch is usually always effective.

Of course we all prefer the dry fly. Trout can be taken on imitations of the dun
because these mayflies tend to stay on the surface a few seconds before
departing the water and they can bring about excellent dry fly fishing. Most all of
the streams in Yellowstone National Park have these mayflies although they are
more important in certain streams than others. The hatch times vary greatly
depending on the elevation of the stream and the current weather conditions.

As a general rule, on the same stream, the
grandis species hatches first and the
dodsi species follows a few days later. This can vary from stream to stream. In
other words, the
dodsi species could hatch days before the grandis species
hatches on a different stream at a higher elevation. In fact, there are green
drakes hatching as late as September in Yellowstone even though they start as
early as June on some streams. Hatches take place in the Northeastern section
of the park much later than they do in the Northwestern section. The
dodsi
species also tends to be found in faster water than the
grandis species.
However, the particular species that is hatching should make little or no
difference to you as far as how you fish the hatch.

I should also mention that this mayfly hatches in many streams outside of
Yellowstone National Park.  In the forthcoming articles, I will cover the fishing
methods for these large mayflies.