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The Feast Below

Learn how and when to fish a caddisfly-pupa imitation, and you won’t be so quick to tie on a dry fly. 
by Bill Edrington
For many anglers, the words caddisfly hatch conjure up visions of epic days, when all you need to carry is a few Elk-Hair Caddis dry flies. Those who anticipate these hatches all winter long spend an inordinate amount of time designing and tying adult caddisfly imitations that will fool trout even in blanket hatches. But, while my experience with spring hatches, particularly the Mother’s Day caddis (Brachycentrus), has taught me that casting these adult imitations can certainly be a lot of fun, trout are often gorged on pupae long before the hatch actually occurs. The reason is simple: caddisfly pupae can drift in the water column—from the streambed up through the buffer zone—for hours and miles until they discover the perfect water temperature and river conditions in which to explode to the surface and become adults.

Large Rainbow Trout
For several hours before adult caddisflies start flutteringoff the water, the pupae enter the drift in great numbers, and trout often fill up on these pre-adults before the visible emergence occurs. Photo: Barry & Cathy Beck

If we ignore this behavioral drift, then we are literally robbing ourselves of hours of spectacular fishing opportunities. Also, after they’ve turned into adults, caddisflies don’t linger on the surface like mayflies do. Instead, they flutter up off the surface almost immediately. That’s why trout make such splashy rises to the dry fly. The trout must make quick decisions, and they often leap out of the water to take the adults before they fly off. The pupae are much easier targets.

Behavioral Modifications
Not all caddisfly pupae drift along without a care. Some species crawl out on rocks, and others—such as the Giant October Sedge (Dicosmoecus)—swim to shore and crawl out of the water before emerging as adults. You don’t have to fish five days a week to learn how to fish a caddis pupa, even though that doesn’t sound like a half bad idea. But you will need to have a rudimentary knowledge of the hatch you are fishing in order to present the pupa pattern properly. Most species of caddisfly drift and swim, often struggling to reach the surface, so that behavior is the one you’ll want to imitate most often.

Case-builders, such as Brachycentrus, and net builders, such as Hydropsyche, drift in the water column during the pupal stage, not as larvae. Many fly fishers swear by larva patterns during these hatches, but their success is probably because there are other caddisfly species, such as Rhyacophila, in the water at the same time. Rhyacophila larvae do crawl around rocks freely, which is why larva patterns can be very effective, especially on spring mornings before the case builders begin to chew out of their cases and emerge as pupae in the drift. By mid-morning, you should be able to pick up fish on deep-running pupae.

You can really help yourself time the transition by using a water thermometer. Although most anglers carry one in their vests, many folks aren’t really aware of when or why to use a thermometer. I’ve found that springtime is the best time to get your money’s worth out of this particular gadget. On an April day, blue-winged olives begin to hatch on cloudy days when the water is around 40 degrees.  On that same day, caddisfly pupae begin to drift in 50-degree water, give or take a degree, with the emergence beginning at around 55 degrees. By using a thermometer, you can make pattern and technique changes that will keep you ahead of the curve.

Caddisfly emergences generally take place in riffle water that is highly oxygenated, so don’t get caught fishing BWOs in flat water when the temperature is right for casting caddis-pupa patterns. That is, unless you want to ignore the fact that, as the number of caddisfly pupae exceeds that of mayflies, most fish will move to the riffles to gorge themselves. Also, I’ve found that mayflies prefer cloudy weather—whereas caddisflies hatch better on sunny, slightly breezy days—so generally you won’t be faced with both hatches at the same time.

When I teach classes on fishing the lifecycle of the caddisfly, I’m often asked when it’s time to stop fishing a pupa and add an adult to the mix. The answer is: When you hear a splash that sounds like someone just threw their dog in the river. Earlier in the cycle, you may see fish slashing at bugs just an inch below the surface, but those fish are generally feeding on pupae that are struggling to become adults. Therefore, when you do put on a dry fly, you should add an unweighted pupa pattern as a dropper, as well.

Drift and Swing
There are several ways to present a caddisfly-pupa pattern, and most of them are very simple. If enjoy dead-drifting nymphs with a strike indicator, simply tie on a deep-running beadhead pupa pattern and let it bounce along the bottom. Cast directly upstream and strip line back at the same speed as the current, or make an up-and-across reach cast and several mends to achieve a long drift. The dead-drift method generally works best with the pupa near the bottom, but don’t be too quick to pick up the line for another cast.

Oftentimes, a fish will grab the pupa on the downstream swing as the fly ascends toward the surface in the current, so be prepared. Keep your rod tip slightly upstream of the fly as it swings downstream. When you feel the weight of the fish or a heavy “tap” on the fly, set the hook by sweeping your rod upstream, parallel to the water—much like a tennis forehand. If you set the hook by lifting the rod tip, you will often pull the fly from the fish’s mouth, leaving you spouting expletives. Don’t forget that a downstream take has everything working against you—the current, the weight of the fish, and your instinct to lift the rod tip—so be patient and let the fish eat the fly before reacting.

 Since many fish feeding on pupae will snatch them just below the surface as they emerge, a downstream presentation—just a traditional “wet fly” swing—makes a lot of sense. Stand in the middle of a riffle, facing the cut-bank shoreline, and cast up and across with a reach cast or curve cast. As soon as the line is on the water and the leader is running properly, make a mend or two to ensure a dead drift as the fly passes in front of you. This should place the fly at its deepest position in the water column. All these steps are necessary to place the fly in the “strike zone” as it starts its downstream journey.

As the fly line passes your downstream shoulder, throw one more upstream mend, and then let the current take the fly. This will allow the current to swing the fly from slightly below the surface up to the film, imitating the natural insect. That movement is what triggers the strike. You can also add action with a few small lifts or wiggles in the drift, which will make your presentation more lifelike. Gary LaFontaine liked to use a “stutter” presentation, which he achieved by holding slack line in his rod hand and releasing the slack in short sections.

Doubling Up
Over time, great caddisfly pattern designers —such as Gary LaFontaine, Gary Borger, and Mike Lawson, to name a few—have designed caddisfly-pupa flies to imitate deep- and shallow-drifting pupae of dozens of different species. Many of the traditional wet-fly patterns designed by notables such as James Leisenring and Sylvester Nemes also mimic caddisfly pupae and are some of my favorites. I’m not going to elaborate upon the virtues of one pattern over the other, but it’s important that you have a clear understanding of when to use one style of caddis pupa over another.

If you want to keep life simple, simply carry olive and tan LaFontaine Sparkle Pupas in sizes 14 through 18. Tie half of them with a beadhead and the other half without. You can then follow the insect’s drift from the bottom to the top by adding or subtracting a split shot or two. Of course, very few fly fishers adhere to simplicity as a philosophy, so there are hundreds of weighted and unweighted pupae to choose from. We all have our favorites.

Rigging a pupa behind a dry fly is a great way to make the most of two stages of the hatch. I use a larger attractor dry, such as a size 14 Stimulator, as an indicator fly over a dead-drifting beadhead pupa. Add a dropper from 18 to 36 inches long—depending on the speed and depth of the water—with a tiny split shot above the pupa to keep it deeper in the column. As fish begin to slash in the film, switch to a foam-body Elk- Hair Caddis trailing an unweighted pupa with about two feet of fluorocarbon tippet separating the two flies. This method allows you to attract fish that want the pupa, as well as those that want a bug with wings. My favorite pupa for this rig is a LaFontaine Sparkle Pupa dropped off a Better Foam Caddis.

At times, just to change things up a bit, I put on a single soft-hackle wet fly, such as a size 12 Brown Hackle Peacock, and swing away. When fish are on a mission to eat every caddisfly pupa in sight, you can literally throw everything in the box at them and be successful to some extent. Just remember the behavior of the species you’re fishing and stick to those techniques.         

Bill Edrington is the owner of Royal Gorge Anglers in Canon City, Colorado, and he’s the author of Fly Fishing the Arkansas, an Angler’s Guide and Journal.

Patterning the Hatch

Patterning The Hatch - An Illustration
Illustration by Jonathan Milo

A series of tandem rigs allows you to fish your way through the hatch, making the most of what’s going on underwater. Start by dead-drifting a large stonefly nymph and a caddisfly larva imitation (A) early in the morning. As the water warms, switch to a large dry fly as an indicator, with a beadhead pupa pattern below (B). Make sure you allow the flies to swing at the end of the drift. When you start to see adults on the water, switch to an Elk-Hair Caddis and an unweighted pupa pattern (C), again allowing them to swing. When the hatch is over, try an Egg-Laying Caddis with a Spent Caddis as a dropper (D).

Kingrey's Bead Caddis Pupa (Olive) Fly
Photo: Dave Klausmeyer

Kingrey’s Bead Caddis Pupa (Olive)
(Larry Kingrey)
Hook: Tiemco 5263,  sizes 14 through 18.
Head: Gold bead.
Thread: Olive, 6/0.
Abdomen: Olive Antron and rabbit,
mixed equally.
Thorax: Antron, cut twice the length
of the hook and teased.
Hackle: Dark dun hen or blue quail.

Emergent Sparkle Pupa Fly
Photo: Dave Klausmeyer

Emergent Sparkle Pupa
(Gary LaFontaine)
Hook: TMC 100, sizes 12 through 18.
Thread: Black prewaxed, 6/0.
Underbody: Green Antron dubbing and cream fur, mixed
Overbody: Green Antron yarn.
Wing: Dark gray deer hair
Head: Brown rabbit dubbing.

Kingrey's Better Foam Caddis (Black) Fly
Photo: Dave Klausmeyer

Kingrey’s Better Foam Caddis (Black)
(Larry Kingrey)
Hook: TMC 100, sizes TK.
Thread: Rusty Dun, 6/0.
Body: Black or Olive closed-cell foam, palmered.
Hackle: Dyed-olive grizzly.
Wing: Natural elk.

Brown Hackle Peacock Fly
Photo: Dave Klausmeyer

Brown Hackle Peacock
Hook: Standard wet-fly hook, sizes 6 through 16.
Thread: Black, 6/0.
Body: Peacock herl, wrapped in a dubbing loop for strength.
Hackle: Furnace or brown hen hackle or soft rooster hackle.

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