Hatch Profile - Pale Morning Duns (PMD)

Hatch Profile - Pale Morning Duns (PMD)

If you had to pick only one hatch to know and understand in Big Sky Country it would undoubtedly be the Pale Morning Dun (“PMD”). This group of mayflies is found on every piece of moving water that holds trout, as well as some of the lakes. Populations of PMD’s are strong in all of our major fisheries, providing an ample food source for area trout in the nymph, emerger, dun, and spinner stages of their life cycle.

Pale Morning Dun is a common term coined by legendary authors Doug Swisher and Carl Richards in their groundbreaking book, Selective Trout in 1971. There are two separate species that make up this important group of mayflies; Ephemerella infrequens and Ephemerella excrucians.

The larger (size 14-16) Ephemerella infrequens generally emerges first with hatches beginning as early as late-May in some fisheries. Ephemerella excrucians can be found emerging throughout the summer lasting as late as October, and can be as small as a size 20. This progression of emergences with bugs getting smaller through the season is often mistaken for the multi-brooded behavior seen in Baetis and Callibaetis mayflies where spring hatches propagate the bugs that emerge later in the season. Rather than one species that continues to emerge throughout the season spawning progressively smaller individuals, the PMD is actually two distinct species with different sizes and sequential emergences.

PMD’s are an important food source for trout at each stage of their life cycle. The nymphs are three-tailed, and can be found in a variety of colors ranging from rusty-brown to black. The abdomen of Ephemerella infrequens has a pale yellow dorsal (top) stripe that is very prominent. PMD nymphs exhibit an interesting behavior where they will move from the bottom of the water column to the top several times prior to emergence. These practice runs have been described as “Pulses of Benthic Drift” by entomologists, and can result in some outstanding nymph fishing preceding the hatch.

PMD duns are three-tailed with light-dun colored wings and generally a pale yellow to light olive colored body. During heavy emergences duns can blanket the water, but crippled, stillborn, and other emerger imitations will often outperform the dun, especially with large fish.

Spinners also have three tails. Their wings are shiny and clear, and the body coloration will range from rusty to olive-brown. Both male and female adults return to the water after mating which results in dense spinner falls when conditions permit.

Weather plays a critical role in PMD activity and corresponding fishing strategies. As a general rule, the nicer the weather, the earlier and lighter the hatch will be; the scuzzier the weather, the heavier and later the hatch will be. On warm, sunny days you might see a sparse emergence in late morning or early afternoon. Cool, cloudy days with precipitation will yield the longest and thickest hatches, but that may not occur until mid to late afternoon. Calm, warm mornings and evenings produce the best spinner falls. The warmer the weather, the earlier in the am and later in the pm the spinner falls will occur.

Regardless of the conditions or the time of day, PMD’s are available in large numbers on all of the major fisheries in Yellowstone Country. So, if you find yourself on the water anytime between the end of May and the beginning of October (especially in June and July), and you’re wondering what the trout are feeding on; you should always start by asking yourself “What are the PMD’s doing?”

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BSA Jojo's Riffle Riser Image 01

BSA Jojo's Riffle Riser

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BSA Jojo's Riffle Riser
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39 Madison Ave

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39 Madison Ave
West Yellowstone MT 59758
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-- Big Sky Anglers Signature Fly Pattern --

This pattern is Joe’s ode to Bob Quigley, the originator of the cripple pattern. During his early years of guiding, when he spent roughly 70 days a season on the Missouri, Joe was always playing around with different cripple flies. At night he would sit at Kuhnert’s house drinking bourbon and tying flies. When the PMD’s would hatch on the Missouri in Mid June the dry fly fishing was off the chain. Joe came up with this variation of the Quigley Cripple way back then and has used it with great success on the Missouri, Henry’s Fork, Madison, Yellowstone National Park, Malleo and the Alumine Rivers in Argentina.


BSA Heames' PMD Klinkhammer Image 01

BSA Heames' PMD Klinkhammer

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BSA Heames' PMD Klinkhammer
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39 Madison Ave

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39 Madison Ave
West Yellowstone MT 59758
United States

BSA Jojo's PMD Image 01

BSA Jojo's PMD

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BSA Jojo's PMD
12
39 Madison Ave

Pickup available, usually ready in 24 hours

39 Madison Ave
West Yellowstone MT 59758
United States

-- Big Sky Anglers Signature Fly Pattern --

Ask any group of veteran anglers around Montana what their favorite hatch is, and you will be sure to get more than a couple of votes for the Pale Morning Dun (PMD). Why? They are found on essentially every rive and stream in our area. They can be found hatching from May through August. They are prolific hatchers, occasionally carpeting the river in awe inspiring numbers. And, to top it off, every life stage of the insect and phase of the hatch presents fun and interesting opportunities to the fly angler.

Afficionados of the PMD are always looking for new imitations and fooling around with old ones. It’s all part of the fun. Of course, Joe is no different, and this pattern of his has proven itself on our home water’s time and time again.


BSA Copenhaver Spinner Rusty Image 01

BSA Copenhaver Spinner - Rusty

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BSA Copenhaver Spinner - Rusty
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39 Madison Ave

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39 Madison Ave
West Yellowstone MT 59758
United States

-- Big Sky Anglers Signature Fly Pattern --

The Copenhaver Spinner is a true to form spinner fly that we love for its durability. This fly has been in use here in southwest Montana for decades and works everywhere from the Madison and Missouri Rivers to Hebgen Lake to the Railroad Ranch on the Henry’s Fork. It is tied in the fashion of a silhouette spinner, with the wings at a slightly less than 180 degrees from one another and is one of easiest to see down-wing spinners on the market. Many spinner patterns are difficult to keep afloat and lack the durability required to be re-cast after landing a feisty trout, but the Copenhaver Spinner keeps on going like the everlasting Duracell bunny. It’s a great fly for blind fishing likely water or a perfect choice as a first fly to present on a selectively rising trout. We love this fly so much we’ve now made it available for PMDs, Rusty, Flavs and Tricos.


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