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Tuesday, February 18, 2014

PMD's on the Lower Yuba River

On the Lower Yuba River we have been seeing glimpses of what is coming as the season progresses and the temperatures start to warm up. On warmer days there have been PMD's floating on down the river. It seems to me that in the last couple of years that they are coming earlier in the season then I remember from years ago. Here's some stuff to get you prepared. Start cleaning those dry lines and organize your fly boxes.

Ephemerella Infrequens - Pale Morning Dun

PMD Spinner

Hatches– February through July on the Lower Yuba
Names: genus Ephemerella
Common Names: Pale morning dun, PMD


NYMPH SIZE: 7-12 mm (1/4-1/2 in)
NYMPH COLOR: Olive-brown, red-brown
DUN SIZE: 7-12 mm (1/4-1/2 in)
DUN COLOR: Wing: smoky gray. Body: pale yellow to tan.
SPINNER SIZE: 7-12 mm (1/4-1/2 in)
SPINNER COLOR: Wing: clear. Body: darker than dun, but still light brown with yellow and olive hints; basically, rusty.
OTHER CHARACTERISTICS: Last two-thirds of nymphs' tails are fringed with fine hairs. Duns, nymphs, and spinners have three tails. Duns and spinners have small rounded projections on the leading edge of the hind wing.



PMD Nymph


About Pale Morning Duns

On the Lower Yuba there is a PMD hatch that starts in early spring sometimes as early as February if the weather warms up. This is one of the better hatches on the Lower Yuba. Pale morning duns have everything going for them, large numbers that trigger aggressive surface feeding, fussy enough to offer a challenge, but not so difficult as to be too frustrating.

This small, pale-yellow mayfly of the crawler group is often referred to by its initials, PMD. Despite the name, pale morning dun, 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 on the Lower Yuba River begins as early as February and lasts as late as September. This is often the dominant hatch when it occurs. Trout take nymphs all day, and duns and emerging duns during the hatch. The best places on the Lower Yuba River to fish for the PMD's are slower runs, back eddies, and tail-outs. 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 may need a thin tippet, sometimes 6X fluorocarbon. You may also need to make a downstream presentation to a fish whose location you are certain of.

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

I will follow this up with a future blog post, "Patterns" for the PMD's



Entomology information gathered from and from Rick Hafele's website

Photos of PMDs from and from

1 comment:

  1. Clay,

    what a great article you put out!!! I have been fishing the Yuba since I was 8 yrs old (27 Now). My parents still live up there. Im there all the time fishing and the information tht you give is so right on... Hope I have luck this weekend... your articles are awesome! Keep em coming!!!


Have any Questions or Comments? Let me know, Clay.