Pale Morning Duns
.............................Fly Fishing Yellowstone National Park

The Pale Morning Duns are found in the slow to moderate flowing waters of the streams
they inhabit. They are crawler nymphs that live for a year. They can swim although not
very well. Like many other nymphs, their exact coloration is somewhat a product of the
stream they live in and the color of the nymphs will vary depending upon the water.
I would think trout eat these nymphs on a regular basis since they are regularly
exposed to them or at least they don't tend to stay underneath rocks like the clinger
nymphs do. They do stay down between the cobble and gravel on the bottom of the
stream. Where there is lots of vegetation they can probably avoid being eaten to some
extent by hiding in the plants. There is certainly no shortage of these nymphs, so there
are plenty of them that don't get eaten by the trout.
Although the nymphs are found in slow to moderate moving water, don't overlook the
fact that this can be in slower, calmer areas of streams that consist mainly of fast,
pocket water. For example, the Gallatin River has a good population. You will find them
in the slower sections of water in pockets along the banks and in pockets behind large
rocks and boulders. They are also found at the ends of long runs and riffles and the
slower moving water on the inside of the river bends. Most streams have as many or
more of these nymphs as any mayfly nymph that inhibits the stream, so fishing an
imitation of the PMD is always a good choice.

You can fish an imitation of the nymph on the bottom anytime during the season prior to
the end of the long hatch. That means from the time the season opens until the PMD
hatches have ended on that stream.
The hatches normally start mid morning. During those days a hatch is occurring, you
can start out with a nymph imitation and continue to fish it up until the hatch starts. The
nymphs swim to the surface and hatch in the skim. Depending on the particular imitation
you are using, you may even want to continue to fish it in the surface skim after the
hatch is underway although there are emerger patterns that I think are much better for
this stage of the hatch.
In pocket water prior to a hatch, I would fish the nymph imitation in the current seams
and the through the long runs. Weight it down with a non-toxic weight and keep it on the
bottom as much as possible. Use a very short, up and across cast and follow the nymph
downstream holding the rod tip high. Continue until the nymph is down and across and
then make another cast a couple of feet upstream of the previous one. You will have to
approach the areas you are fishing carefully to avoid spooking the trout when you are
making this short of a cast.
In smooth water you will need to make a much longer, up and across presentation
and keep the nymph on the bottom by weighting the tippet a few inches above the fly
and continuously mending the line.
Smooth water in rivers such as the Madison and Firehole is deceptive. The current is
usually very strong even though the water is smooth. There is a lot of vegetation that
your fly will hang on unless you select the areas to drift your nymph through. It is also
difficult to keep a drag free drift in the swirling currents.
I watch the end of my fly line to detect strikes but you may prefer to use a small strike
indicator. Fish the nymph until it is in the down and across position before making
another cast.

Coming Up Next:
Pale Morning Duns -Emergers

Copyright 2008 James