Fly Tier's Bench: Shallow-Water Stones

This article originally appeared in the May 2007 issue of Fly Fisherman.

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When spring runoff subsides and temperatures start to climb in Montana, mature nymphs of the giant Salmonfly and the Golden Stone become active in preparation for their annual emergence. Stonefly nymphs require plenty of oxygen, and they find it in rocky, turbulent shallows. When their biological timers go off, they migrate to shore, where they climb from the water and hatch into adults.

At the same time, trout are coming off their lean season and require gobs of protein to keep pace with their quickening metabolisms. They find this in the form of inch-long stonefly nymphs. Since most stonefly nymphs are in the shallows, so are the trout. This assertion is not based on science, but on the conviction of a fisherman who has spent an inordinate amount of time concerned with the relationship between stonefly nymphs and trout.

I routinely hook my biggest fish of the year during the weeks before a Golden Stone or Salmonfly hatch. And I concentrate on water that traditionally wouldn't be considered prime holding habitat for trout. The quieter seams, riffles, and runs are typical trout targets. But when trout are feeding on stonefly nymphs, they can afford to expend the extra energy fighting swifter current-the calories gained outweigh the calories spent. This seems to be especially true of bigger, older trout that have been through a stonefly season or two.

Shallow-Water Holds

Stoneflies live in unpolluted, rocky, fast-flowing rivers. Stonefly nymphs abound in gravel bars, where swift currents dislodge them into the mouths of hungry trout waiting in the structure. I have seen trout holding in inches of whitewater at the head of a gravel ledge. Bigger trout often guard these prime feeding locations right where the ledge drops off, ensuring they get first dibs on the nymphs.

Look for small depressions in or below gravel bars, with just enough depth to hide a trout. Since fish cannot remain stationary in the swift current, their dorsal or tail fins sometimes give away their shallow positions. Sight-fishing in this type of water is a rare treat in fly fishing.

Current breaks created behind submerged and half-submerged boulders also make for noteworthy nymphing water, but knee-deep, rushing whitewater may not be the first choice to run a Pheasant Tail through. However, when the snack is stonefly nymphs, these spots hold big trout.

Rolling Stones

There's one such spot I fish every spring. The turbulent water is about 2 feet deep, and I avoid this piece at any other time of the year. But in May it's packed full of trout. Softball-size rocks line the river bottom, making it an ankle-buster of a wade, and stonefly nymphs by the thousands crawl to the shore. The adult insects drying their fresh wings on the grass­lined bank of this honey hole reveal the river's secret.

Stonefly nymphs are bottom dwellers, and therefore the fly needs to move deep along the rocks. I used to fish stonefly nymphs under a strike indictor but found this often pulled my fly out of the zone. By fishing a lone stonefly nymph I maintain contact with the bottom, delivering a more natural presentation. I also find this type of fishing more pleasant than bogging my leader down with yarn, split shot, and dropper flies. And the takes are aggressive enough that they are easily discerned from hang-ups.

To fish stoneflies without an indicator, cast the nymph almost straight upstream and strip the slack to keep up with th9 drift. Allow the nymph to bounce along the bottom. Tighten the line and use the, rod tip to maintain contact with the, bottom by gently jigging the fly. In pock­ etwater or shallow riffles, fish the watenl tight to shore first and then move toward 1the center. Even if the current is fast, it'sl usually shallow enough to wade and cover the whole run with this tight-line presentation. If I need to cast farther to cover a bucket I can’t wade to, I make a small downstream mend where the fly line meets the leader, creating a tiny belly. This "U" in the line acts as a strike indicator–when it straightens out, set the hook. While this technique drags the fly a little, it doesn't bother the trout, which may mistake the action for the crawling motion of a stonefly.

There is no need for a tapered leader with this presentation. Selectivity isn't an issue when fishing heavy water, and a level 3X leader tied directly to the fly line serves the purpose. A short 5-foot section is effective and manageable for shallow-water presentations.

Keystone Construction

When I was experimenting with shallow-water stones, the inherent problem was constantly losing flies, including “fancy” versions that took 20 minutes to tie. The good old Girdle Bug served me well as a quick tie, yet I still grew weary of tugging on the river bottom and attaching new flies when I should have been fishing.

Along with the evolution of my stonefly strategy came a pattern to complement it. The Keystone was born. This fly is designed to ride hook up, which results in fewer bottom snags. I often fish all day and lose only one or two flies.

People ask me why I tie the dumbbell eyes on the bottom of the hook instead of the top if it's designed to ride hook up. Originally I tied the eyes on top to get it to keel over, but it didn't have the right aesthetics. So I tried tying the pattern on a bent hook, adding lead to the angled part of the shank, and tying the eyes on the underside of the hook. This design still achieves the desired effect of turning the hook up, and it looks prettier in the fly box. I have tied it this way ever since.

The Keystone in sizes 4 through 10 has enough weight to find bottom, but is not difficult to cast. Though I usually fish it in fast water where trout have less time to be picky, it also fools finicky fish on one of my home rivers, the Metolius, which I consider a sound testing ground for trout flies. It has also proven deadly on every other stonefly stream I've cast it into from Oregon to Montana. I tie the pattern in black, brown, golden, and olive.

My most memorable stonefly experiences often include giant dry flies and splashy rises. My most memorable fish, however, comes well before I tie on my first bushy dry fly.

Black Keystone Fly-Tying Recipe

• HOOK: #4-6 Daiichi 1730 or Dai­Riki 700B.
• THREAD: Black 6/0.
• WIRE: Nine wraps .035" lead-free wire.
• EYES: Black 5/32" Dazi-Eyes.
• RIB: Black vinyl rib, large.
• DUBBING: Black SLF, Trilobal, or comparable.
• WINGCASE: Brown Scud Back.
• GILLS: Hungarian partridge (brown feathers).

Golden Keystone Fly-Tying Recipe

• HOOK: #6-8 Daiichi 1730 or Dai­ Riki 700B.
• THREAD: Brown 6/0.
• EYES: Black 5/32" Dazi-Eyes, or 1/8" for #8 and #10.
• RIB: Amber vinyl rib, large or medium.
• DUBBING: Trilobal Golden Stone or SLF.
• WINGCASE: Brown Scud Back.

*This pattern can also be tied in brown or olive in various sizes to imitate any stonefly nymph.

Keystone Nymph Step-by-Step Tutorial

Justin Karnopp is a freelance writer and photographer from Missoula, Montana.

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