Techniques- Fishing the PMD Hatch

Last year Blake Larsen and I had dropped my drift boat into the Lower Yuba River and I was rowing upstream to a large eddy pool where we typically start our fishing. As I rowed upstream we noticed lots of swallows buzzing the river. They were gobbling up PMD's as they took off from the surface film and headed into the air. The PMD's were running the gauntlet. I anchored and we watched this happen for about five minutes. If 5 out of a hundred PMD's made it to safety without becoming a meal that may be exaggerating. It was a feast for the swallows that's for sure. I bet you can guess how we rigged up.

The Hatch
Pre- Emergence
The nymphs of these species, like all Ephemerellidae, are known as crawlers due to their habit of crawling over the substrate and generally poor swimming ability. While crawling along the stream bottom the nymphs feed on algae and decaying vegetation such as leaves and wood debris. Nymphs frequently get washed into the currents, and because of their abundance this “drift” provides important food for trout. It also means that nymph imitations are important, especially in the weeks and days prior to emergence. The wide distribution and abundance of these species also means nymph imitations can be successful searching patterns most of the year.
For nymphs a dark gold ribbed Hares Ear, pheasant tail, Skip's Nymph or HBI tied in the appropriate size (18-14) will usually do the trick. There are of course many match the hatch patterns as well. I find the above patterns work very well. It's pretty simple. Do some sampling, catch some bugs, put them in a white tray or lid, drop your nymph patterns into the lid and see what matches. Nothing to it. Go fishin'.

Some people say that using bead head patterns will help get them to the bottom. I like to fish with non-bead head flies and just use split shot to get them down. Fish them dead-drift along the edges of and below riffles, through pocket water or along undercut banks. Nymph patterns are most effective just prior to emergence when the naturals are migrating to slower water or beginning their restless ascent to the surface for emergence. On the Lower Yuba weighted flies and split shot are necessary to get the flies near the bottom during the early stages of the hatch when most nymphs are still on the bottom. Later nymphs can be effectively fished in mid depths without weight. A strike indicator located six or seven feet above the fly, is a great help for detecting strikes when fishing these small nymphs.


Stage One - Nymphing

During the hatch's early stages fish are focused on PMD nymphs and emergers, so most of the action is subsurface.

Indicator Nymphing -

Rigg up with a nine foot 3x leader. Add 16" of 4x flurocarbon to attach your 1st nymph, (maybe an HBI), place shot at the knot at the end of the 3x leader. Tie another 14" section of 5x tippet to the hook bend of your 1st fly and the add your second fly (maybe an Pheasant tail). If your brave enough add a third fly. Attach a "Boles Indicator" and set it at about 7 to 8 feet to the shot. Adjust the depth as necessary. Note: Try using the "Davy Knot" for attaching your flies to the tippet.

Use standard upstream indicator tactics to present the nymphs when wading.

Tight Line Nymphing
Use a nine-foot 5X leader and tie on the your favorite PMD imitation. Put enough 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 – Emergers and Duns
Changing from nymph to dun is often a trying task for these mayflies. When everything goes right the nymphs hang in or just under the surface as the wings of the dun escape the nymphal shuck and break through the surface. This is a good time for a floating nymph pattern. Often, however, not everything goes right. Duns with wings partially unfurled get caught in the surface and never get off the water. Soft hackles or flymphs make excellent emerger patterns when this occurs.

Fish floating nymphs or flymphs upstream and across with a dead-drift float. I prefer casting to fish I’ve spotted feeding just under the surface on emerging duns. However, even fish clearly taking duns will often take a well presented emerger after refusing numerous dun patterns.
Surface activity can be fast during the often heavy hatches of these mayflies. For this reason a good durable dry fly can save a lot of time from changing flies between fish. Compara-duns have proven themselves very durable and imitative. In recent years, however, I have found “Harrop” duns (originated by Rene Harrop) to be equally durable and more effective at fooling selective fish. Fish during these hatches can become ultra selective. Patterns from 14’s to 20’s may be needed depending on the local species and conditions. The color of the naturals varies on the Lower Yuba River and sometimes we have noticed two differents PMD’s hatching at the same time. It’s always best to collect a hatching dun and select a pattern according to its size and color. You should rigg up with 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 which are states that trout particularly focus on. Delicate presentations and drag-free floats are a must when fishing dries during these hatches. If you are getting refusals with an upstream cast, try a downstream slack-line presentation. To achieve a downstream drag free float, try a pile cast, where the line and leader to fall down in a heap about five feet above a rise. 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. If that fails and naturals are seen fluttering on the surface struggling to get airborne, try giving your fly slight twitches.

Spinners
Finally, watch carefully for spinners in the evening. They can be surprisingly difficult to see in the fading evening light. Rises to spinners are also subtle. A simple hackled fly clipped top and bottom makes a good spinner pattern. A downstream slack-line cast, carefully positioned over the feeding lane of a rising fish, is usually the best approach.

Research for this article from;
Rick Hafele's website www.laughingrivers. com

Westfly at www.westfly.com