Bighorn River PMD Hatch Information

Bighorn River PMD Hatch Information

February 5, 2011 10:14 am Published by

Bighorn River Pale Morning Duns


PMD Nymph

Early stage PMD Nymph - Notice the slender body of this ephemerella nymph

Pale Morning Duns are the largest mayfly we have on the Bighorn and are one of the most exciting hatches to fish each year. The PMD hatch occurs at the end of June or July each year typically as the higher flows from spring runoff recede.

The Pale Morning Dun hatch will get going when the water temps hit the low to mid 50s. If the river level comes up to the point they draw water off the top of the dam, this will happen sooner in the season. If they don’t draw water off the top of the dam, this will cause the hatch to start occurring a little later.

As with any hatch, there is no guarantee that you get the right conditions for rising fish, so arm yourself with nymphs and subsurface emergers as fish will often key in on emergers more than newly hatched adults. The nymphs will be active early in the day as they start moving around prior to the hatch.

When it comes to dries, floating cripple can be very effective. Since these mayflies like to hatch during the warm days of summer, they don’t spend a lot of time sitting on the water. A cripple that isn’t going to hatch is an easy meal and can bring up fish that feeding on various stages of the hatch.

Splitback PMD

Notice the wing case is "split" as the adult is in the process of emerging from the nymphal schuck

As with many mayfly hatches, an added bonus is the spinner fall. Spinners can start hitting the water in late afternoon or early evening and last until the next morning. Spent mayflies are the easiest meal of all so watch for noses in foam and on the slow side of seams where spent mayflies will accumulate.

Bighorn River Fishing Tip:  Pale Morning Dun nymphs are especially effective on the Bighorn, do not over look them.  Trout will key in on the nymph even if they are not feeding on the surface.

Emerging PMD

PMD about to emerge and dry it's wings

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This post was written by Bighornangler

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