Pale Morning Dun

Other Common Names: PMD
Scientific Names: genus Ephemerella

One of the great hatches of the West, pale morning duns have everything going for them: massive numbers that trigger aggressive surface feeding; a presense on nearly all the waters of the West; fussy enough to offer a challenge, but not so difficult as to be too frustrating; and they occur during the summer months when fishing is at its most pleasant.

This small, pale-yellow mayfly of the crawler group is often referred to by its initials, PMD. Despite the name, hatches can occur in the morning, early afternoon, or evening. It's not unusual to have both morning and evening emergences on the same day. The hatch season begins as early as June and lasts as late as September, depending on the stream. This is often the dominant hatch where and when it occurs.

Trout take nymphs all day, and duns and emerging duns during the hatch. The best places are slow runs, backeddies, and under overhanging vegetation. Shortly before a hatch, dead-drift a nymph near the bottom. As the hatch begins, present a nymph near the surface or as a rising nymph. As trout begin taking duns off the surface, tie on an emerger, cripple, or dun pattern.

Because the hatch usually happens in slow, clear water you will need a thin tippet--7X on many spring creeks. You may also need to make a downstream presentation to a fish whose location you are certain of.

Entomologists used to split this species into E. inermis and E. infrequens, E. inermis being smaller but much more numerous. However, both have now been lumped into E. excrucians.

The spinner stage is almost as important as the hatching duns. Spinners are usually well matched with the classic Rusty Spinner .

 

How to Match a Pale morning dun

Hatches are matched from Westfly's database of "standard" fly patterns.

Nymph
Size 16-18 Pheasant Tail, Hares Ear. Pale yellow, light brown, or tan body; light wing
Flats, moderate runs, backeddies: indicator, tight line, rising nymph, shallow nymph
Emerger
Size 16-18 Sprout Midge, Film Critic, Hackle Stacker. Pale yellow, light brown, or tan body; light wing
Flats, moderate runs, backeddies: standard dry fly
Dun
Size 16-18 Sparkle Dun, Hairwing Dun, Comparadun. Light brownbbody; light wing
Flats, moderate runs, backeddies: standard dry fly
Spinner
Size 16-18 Rusty Spinner. Light brownbbody; light wing
Flats, moderate runs, backeddies: standard dry fly

 

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Characteristics

NYMPH COLOR: Olive-brown, red-brown

DUN SIZE: 7-12 mm (1/4-1/2 in)

DUN COLOR: Wings--smoky gray. Body--pale yellow to tan

SPINNER SIZE: 7-12 mm (1/4-1/2 in)

SPINNER COLOR: Wings--clear. Body--darker than dun, but still light brown with yellow and olive hints; basically, rusty

OTHER CHARACTERISTICS: Nymph-last two-thirds of tails are fringed with fine hairs; three tails. Dun and spinner--three tails; small rounded projections on the leading edge of the hind wing.