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

New KISS Bug Series - Part 24

Pale Morning Dun

Most of the time the Pale Morning Dun or PMD emerge just like their name implies - in the morning.
In Yellowstone National Park this is usually about 9:00 am to 11:00 am. Like many other mayfly hatches,
the activity usually last only a short time, an hour or so, although it may go on much longer during cloudy,
overcast days. These mayflies definitely prefer hatching under low light conditions because the early
season hatches may extend for a few hours when it's misting rain or lightly snowing.

The PMD nymphs swim to just beneath the surface of the water to shed their nymphal casing. It's during
this time that the nymphs are suspended that the trout have the best opportunity to feed on the emerging
duns. The emerging nymphs are completely helpless at this point and the trout know it.

Our Perfect Fly emerger imitations fished in the surface skim are usually very effective during a hatch. In
fact, in most cases they are actually more effective than the dun imitations. There are two different types of
Perfect Fly emergers - one we call a plain version, and the other a trailing shuck version. The plain
emerger pattern is more like the nymph than the dun and the trailing shuck version is a little more like the
dun than the nymph.

The emergers are more difficult to fish than the dun imitations because they are not as easy to see on the
water. Some anglers do better with the duns than the emergers because of this and others have much
better success fishing the emergers. The plain emerger is a biot body fly tied on a curved hook with a CDC
wing that floats flush with the surface skim. The trailing shuck version has a biot body tied on a straight
shaft hook with an antron tail or trailing shuck that imitates the nymphal shuck attached to the dun just prior
to coming off.

Normally, PMD nymphs migrate from the moderate sections of water to hatch in calmer, slower moving
water that's near their normal habitat. A long leader and tippet of 6x or even 7x will get far more takes from
the trout than something shorter and heavier, but 5X tippets will work in most cases.

If you are fishing pocket water, you are much better off fishing the calm areas of water within the stream
using an up stream, or up and across presentation. The Pale Morning Dun nymphs will hatch in the
pockets behind large rocks and boulders, in pockets along the banks, and anywhere except the faster
flowing water.

Smooth flowing water can require a down stream, or a cross-stream presentation. It may even require you
to fish to individual rising fish. In this case you will need longer leaders and tippets. We normally use a 12
foot overall length of the leader and tippet in downstream presentations.
Copyright 2012 James Marsh
Pale Morning Dun:
Availability to trout:             
Hook Size:                          
Type of water:                    
Emergence time:                
Duration of hatch period:
PMD Cripple - Click image to enlarge