tactics

Salmonfly Nymphs

By Mike Schoby

Salmonfly nymphs are a the Big Mac of the river, an irresistible morsel for trout. Spring and fall are the best times to cast their imitations.

Images

(See the entomology page for photos)

t was the first time I'd fished the Madison River in Western Montana, and the morning was dragging by with out so much as a bite. We had stopped at the local fly shop to read their "fly of the week" board and had followed their advice: Elk Hair Caddis, Whitlock Hoppers, and Hares Ears.

The trout hadn't read the "fly of the week" board, though, and they ignored our offerings. "This is supposed to be a blue-ribbon river?" I thought to myself.

We stopped for lunch at a local eatery. The proprietor found out we hadn't had any luck, and said, "You're fishing black stonefly nymphs, right?" We all looked at each other and slowly shook our heads. "If you want to catch fish at this time of year," he said, "you have to use large black stonefly nymphs. Kaufmann's Stonefly, Rubber Legs. Stuff like that."

We quickly headed over to the fly shop to stock up on our new "secret" and discovered that it wasn't much of a secret: the shop didn't have a single Kaufmann's Stone or Rubber Legs in stock. All of those boxes were empty. But they had plenty of Grasshoppers, Elk Hair Caddis, and Hares Ears to sell to the ignorant tourists.

We rummaged through our boxes and found a half-dozen good Kaufmann's Stones, and back to the river we went. It was like a miracle. Previously "vacant" waters were now teeming with large rainbows and browns that were practically standing in line to pounce our nymphs.

Salmonfly Nymphs

Salmonflies (Pteronarcys californica) can produce some terrific nymph fishing, especially in the spring and fall. These big insects are prolific in most cold, clean streams of the West. Due to their size they become a staple in the diet of large trout.

Salmonfly nymphs live on bottom, crawling around on rocks and in the spaces between rocks. They require well-oxygenated water, so they thrive in fast, riffly stretches of the river.

Living where they do, it isn't unusual for them to get knocked loose into the current. This can happen during the normal course of their three-year underwater life, but it is especially common in the spring when mature nymphs migrate towards shore. If a nymph is lucky, it reaches shore, climbs out on a rock, grass stem, or tree branch, and emerges into an adult. But many nymphs are not so fortunate. They are knocked loose and drift into the mouth of a waiting trout.

Casting and Presentation

Once dislodged, the nymphs tumble across the bottom. It is very rare to find them higher in the water column. Therefore your fly must also bounce along the bottom to be effective.

A good way to achieve this is to use a heavily-weighted fly tied to a 2X or 3X tippet. Use a floating line and an indicator, such as a corky or some other commercial product. Since the fly is heavy, large strike indicators work best.

The combination of a very heavy fly and a wind-resistant indicator makes this a hard rig to cast. You can't cast it like you would a size 16 dry fly. Short upstream pitches usually work best. Open up your casting loop and slow down your timing. Don't expect to make casts longer than 20-25 feet.

Cast upstream and let the fly and indicator drift downstream. Treat the indicator as you would a dry fly, and make whatever mends are needed to achieve a natural-looking dead drift. If you minimize the amount of slack line on the water, you'll get a better drift and you'll be able to strike more quickly.

Let the fly drift past you and cover some of the downstream water. Once the fly starts to swing, though, it won't catch many fish. On the other hand, if you let the fly drift until the line stretches out tight below you, it's easier to make your next upstream cast. That's because the drag on the fly and line helps to load the rod. In fact, if you give a quick haul just before your forward cast, you can fling the fly upstream without much effort and without any false casts.

Needless to say, a good 5- or 6-weight graphite rod is needed for this kind of fishing. Try it with a 3-weight, and you'll destroy the rod in short order.

Where to Fish

Three types of water are especially productive when fishing salmonfly nymphs:

1. Current seams, where fast water is next to slow. Let the fly drift through the slow water just next to the fast current.
2. Slower, deeper water just downstream from a fast, shallow riffle.
3. Boulder fields and areas of large rocks where the water is two-four feet deep.

It is usually best to start fishing at the downstream end of a likely stretch of water. Cover the water just above you thoroughly. Then walk upstream about five feet and do it again.

Setting the Hook

Unlike most nymph fishing, where the hook is set at any hesitation, wait until the strike indicator get completely dunked. If you're fishing correctly, the strike indicator will constantly be stopping and jerking slightly as it bounces its way downstream. Do not mistake these slight tugs for fish; when trout hit it, they usually take it hard.

Strike with both hands: swing the rod downstream while pulling in line with your free hand. The reason for this is that there is a lot of slack in the line. If you don't get the slack out quickly, the fish will reject your fly before you can set the hook.

Fly Patterns

There are many good patterns that imitate these nymphs, but my all-time favorite is the Kaufmann's Stonefly. It is the most realistic of all the patterns, both to the human eye and, apparently, to the fish.

The Kaufmann's Stonefly has a heavily-weighted and flattened underbody of lead wire. Some tiers also add a heavy beadhead for additional weight, and some add rubber legs as well.

The Rubber Legs or Girdle Bug is another good imitation. The Brook's Stone works well and is an easy tie. The theory behind the Brooks Stone is that your fly will tumble as it drifts (more than the natural insect) and this "tied in the round" style presents the same silhouette regardless of the fly's orientation. The Montana Stone is a traditional pattern that is still used in the Rockies, although few Northwest anglers tie one on.

The Kaufmann's Stone is time-consuming to tie. For this reason, some anglers use the less realistic--but faster-to-tie--Rubber Legs in fast or murky water where trout don't have much time to look at it, and use the Kaufmann's Stone in slower, clearer water.

Salmonfly nymphs can be black or chocolate brown. If you want to be fussy, take a sample from the water you're fishing and tie on a fly of the appropriate color. Most anglers just fish black patterns, however.

Seasonal Factors

Because salmonflies hatch in late spring, that is a good time of year to cast a nymph imitation. The prime time is begins about two weeks before the hatch starts.

Anglers who fish rivers with large populations of wild rainbow trout should take particular care when casting nymphs during the spring salmonfly season. Rainbows spawn in the spring, and you can snag spawning fish if you dredge the bottom with your big, heavy fly. If you suspect you're in an area where trout are actively spawning or recovering from spawning, move on and fish a different place. Some anglers refuse cast salmonfly nymphs in spring because they are concerned about putting additional physical stress on spawning wild trout.

When the hatch is over, the remaining nymphs, which are two-years old, are smaller than those that just hatched. So you might want to use a smaller nymph imitation.

While trout will take salmonfly nymphs twelve months of the year, they generally shift their focus to other insects after the spring hatch season. By September, however, they are again receptive to salmonfly nymphs.

Uploaded 09/04/2000.

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