.......................  ....................  ...Fly Fishing Yellowstone National Park
05/22/12

New KISS Bug Series - Part 25

Pale Morning Dun
Duns










The Pale Morning Dun, or Pale Morning Dun Dun, is the stage of life of this mayfly that interest most
anglers. Watching your PMD imitation float down the smooth section of a stream, suddenly interrupted by
the slurp of a large trout grabbing it from the surface of the water "is what it's all about". It doesn't get any
better than that.

The duns tend to drift for a good ways downstream during the early part of the hatch. They take their time
drying their wings enough to get airborne although I'm sure they do all they can to speed things up. A long
time isn't measured in minutes. A long time is several seconds or a minute or two. Many never get off the
water. These are called cripples and have some type of deformity or something that prevents the mayfly
from being able to fly.

These mayflies don't emerge in fast water or even strong moderate currents. In most cases they will move
from their normal moderate flow habitat to nearby slower moving water to emerge. In pocket water streams
this is usually the pockets behind boulders and pockets along the banks of the stream. It can also be the
tailouts of pools and slower moving water in the flat areas of this type of streams.

Prior to hatching In moderate speed, smooth flowing water they will move out of the current to slower
moving water along the banks and any area of the stream where the current isn't as strong. The smooth
flowing water can really be deceptive. It can make it more difficult to get the fly to the trout in a drag-free
manner in some cases. The slick areas of the Firehole River provides the perfect example of this problem.
Although the smooth flowing surface of the water looks almost slick, it can contain some swirling currents
that will grab your fly line a send the trailing PMD dun skiing across the surface like it has a tiny outboard
motor attached to it. .

A down-stream or cross-stream presentation will usually spook less fish although in pocket water streams
you can fish the calm water pockets with an upstream presentation effectively. We fish upstream, or slightly
up and across anytime we can do so without spooking fish. This is always the best presentation in streams
with fast moving pocket water. Of course, presenting the Pale Morning Dun imitation in the calmer pockets
isn't always easy. If much of your fly line is on the water, chances are the fast water will grab hold of the line
and send the little dun skiing. It's best to make short cast and keep all of the fly line you can off of the water.

In slower moving, slick or smooth water, you may need to fish down and across. It there are not a lot of
trout rising to the emerging duns,  you may even need to fish to individual fish. This is a matter of getting
your fly to drift over the fish at just the right time.

During the months of July and August, when the PMD hatches are occurring on some of the colder streams
in Yellowstone National Park, you may make the mistake of starting to fish too late in the day. The hatches
generally take place earlier during the hottest days of the season. You may need to be on the stream
fishing by 9:00 o'clock in the morning which many anglers consider early, especially if they fished late the
day before. The hatch may be over by 10:30 to 11:00 am.
Copyright 2012 James Marsh
Pale Morning Dun:
Species:                             
Type:                                  
Availability to trout:             
Hook Size:                          
Numbers:                            
Distribution:                        
Type of water:                    
Emergence time:                
Duration of hatch period:

Ephemerella infrequens/ E. inermis
Crawlers
Excellent
16/18
Heavy
Widespread
Moderate to slow - smooth and broken surface
Mornings
Long