tactics

Stages of the PMD Hatch

By Greg Thomas

Pale morning dun hatches go through distinct stages. Learn to recognize each one and match your flies and tactics to what's happening on the water.

he dog days of August portend midday temperatures that reach into the 90s--and maybe beyond--in the mountain West. However, that doesn't mean that fly anglers need to hang up the rod until cooler weather arrives. They just need to adapt to the conditions.

Adapting means fishing early in the morning or late into the evening. (That eliminates many of my fishing partners: they are notoriously lazy in the a.m., and when the sun goes down they are either kicking up their heels at a local nightclub or, more so lately, demonstrating their spousal loyalty by plopping down on the couch to watch sitcoms!)

In the early morning, massive trico hatches and spinner falls dominate the scene. See the feature Tricos Without Tears for tips on handling that hatch. In the evening, another diminutive bug is on the water: the pale morning dun, or PMD.

Flies to Carry

Most August evenings you can expect a PMD hatch on the rivers of Montana and Idaho. Typically, the hatch begins between 5 and 8 p.m. Anglers that mechanically tie on a dry fly will catch some trout, but those who adapt their tactics to the different stages of the hatch will do much better.

To fish the stages of the hatch, carry at least four fly patterns (all in sizes 16 and 18):

1. Lightly weighted Pheasant Tail nymphs
2. Yellow, olive and pink Sparkle Duns
3. PMD Cripples
4. And the old standby, a few parachute Adams.

Stage One

During the hatch's early stages--starting around 5 p.m. or 6 p.m.--fish are focused on PMD nymphs and emergers, so most of the action is subsurface. Use an eight-foot 5X leader and tie on the Pheasant Tail. Put a small split shot on the leader about eight inches above the nymph. Cast downstream and across, allowing the nymph to sink to the bottom, then swing across in the current. Trout will take the fly as it rises from the bottom during the downstream swing.

Stage Two

As more bugs come off and more fish rise, change to an 11-foot, 6x leader and replace the nymph with a Sparkle Dun or PMD Cripple. Sparkle duns and Cripples are nice representations of emerging duns or duns trapped in the shuck--states that trout particularly focus on.

When imitating this stage, a drag-free drift is essential. To achieve it, try a pile cast, where the line and leader to fall down in a heap about five feet above a rise (you are making a downstream presentation). Make two quick strips to separate the fly line from the fly. The current will gradually straighten the tippet, but not before the fly floats naturally over a trout.

Stage Three

Sparkle Duns and Cripples may work throughout the hatch, which may extend past midnight. However, by 9 p.m., there are enough fully-emerged duns on the water to make a Parachute Adams a good choice because the white calf-tail post makes the fly more visible when the light is low.

Greg Thomas is a widely-published fly fishing writer

Uploaded 08/01/1999.

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