Dry Fly Fishing Course

Prospecting

Introduction

Now that we’ve covered insects, types of water, and the finer points of presentation, it’s time to turn our attention to what happens on the water when we fish. As is always the case in dry fly fishing, the fish will tell us what to do. Sometimes we go to the river and some sort of hatch is underway and the fish are rising. A higher percentage of the time, however, we’ll get to the river and nothing will be rising. Perhaps there are no bugs or only a few bugs on the water—not enough to get eating going on the surface. In this case, the dry fly angler turns to prospecting.

Lesson Outline

Prospecting refers to casting a fly to likely pieces of water when no fish are visibly rising. Though prospecting is a very common approach today, this wasn’t always the case. On the chalk streams of England where dry fly fishing was modernized and codified, British anglers called this approach “blind casting,” and it was considered unsporting and even illegal. Of course, since the chalk streams of that era were legendary bug and fish factories, anglers typically didn’t need to wait long for a pod of fish to rise.

That all changed when fly fishing crossed the Atlantic Ocean. When New World dry fly anglers started to ply the freestone rivers of the Catskill Mountains, they noticed that hatches were less frequent, less intense, and less sustained than in the biologically rich spring creeks of the Old Country. If an angler waited for a rise form to begin fishing, they might be waiting a very long time indeed. These anglers quickly discovered that fish who might not be actively rising were nonetheless amenable to a well-presented dry fly. Free from the cultural constraints of English gentility, they started a new way of dry fly fishing: prospecting. Thus was born the Catskills-style dry fly, which, compared to its Old World predecessors, was much more aggressively hackled and therefore floated higher on the water. This style of fly allowed the New World anglers to cast again and again over the turbulent waters of New England streams as they searched for willing fish. The legacy of those anglers continues today.

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Why Prospect?

Reasons Prospecting is Worth Your Time

There are plenty of reasons to prospect when no fish are rising. The first and best reason is that you just want to experience the pleasure of fishing a dry fly. Aside from that, however, there are several reasons why the omnivorous angler—that is, the angler who fishes all methods without bias—might want to prospect with a dry fly instead of fishing a nymph or streamer when fish aren’t rising.

Covering ground, moving fast

When prospecting, you can move as quickly as you want to, dropping strategic drifts into the best looking spots as you look for aggressive fish.

Low Water

Low water requires stealthy presentations at distance, and it’s more difficult to accomplish this with weighted offerings like nymphs and streamers, which land with a plunk. The dry fly angler, however, can sneak up on fish from a good ways off.

Another reason low water is excellent for the prospecting dry fly angler: it decreases the vertical distance between a given trout and all types of surface food. High water, on the other hand, increases vertical distance, and is typically associated with poorer dry fly fishing.

Underwater wood and weeds

Fishing gnarly logjams or underwater vegetation is impossible with a nymph and it can also be hazardous going into these zones with a streamer. A dry fly, however, can skirt above any and all underwater obstacles as it lures trout of the thick stuff to eat.

When big bugs are present

Even if no hatch is on at that exact moment, when big bugs are in the general area it often means good fish can be made to rise to an aggressively fished imitation. Sometimes (to riff off of Gandhi) you must be the hatch you hope to see in the world. Prospecting just outside major hatch windows can result in great fish and buy you hard-won solitude, since in many places great hatches also mean tremendous angling pressure.

Prospecting and Time of Day

Light is key for the prospecting angler. Early and late in the day when the sun is off the water makes trout feel more comfortable moving for a meal. After that, cloudy days are more desirable than bright, sunny days. Humidity is an added bonus: an angler confronted with a mild, cloudy, humid day can be in for some excellent prospecting with the dry fly.

Prospecting Through the Seasons

In general, prospecting first becomes effective once the hatch season on a given watershed commences, which gets the fish “looking up.” That said, when exactly fish start “looking up” varies by region, river, and type of river. That said, plenty of die-hard anglers start fishing dries well before they should, because they enjoy fishing, they want to get their skills up to speed to be ready by the time good dry fly fishing begins in earnest, and, well, because they’re optimists. So, technically, a good time to prospect with a dry is “whenever you feel like it.”

Once the hatch season commences and fish start to feed on the surface with some regularity, prospecting really hits its stride. In the spring and early summer months, prospectors do best with flies that generally imitate the local forage: mayflies, stoneflies, caddis, and odonates. Once the heat of summer hits, prospecting with terrestrials becomes a great way to catch numbers of fish, as well as bigger specimens. Trout on a terrestrial bite are very opportunistic since terrestrials with their substantial mass don’t need to be on the water in great abundance to get fish looking for them.

Why Trout Eat Opportunistically

A Trout’s Calculus

If prospecting is an act of persuasion to a trout that may or may not be interested in actively eating, we need to understand our audience and ask the question: What constitutes the right opportunity for a given trout to eat? The two primary persuasive tools the prospecting angler has to seal the deal with a potential fish are proximity and profit. By anticipating fish location and making a cast that puts the fly in the strike zone, we are saying to the trout: you don’t have to move that far to eat. That’s proximity. And by providing a substantial meal, we are telling the trout that the act of eating this bug will result in caloric gain. That’s profit.

Here’s a human analogy to further contextualize things. If you are walking down the street, you aren’t likely to stop and stoop to pick up a penny in any circumstance, but you might bend down to pick up a quarter right at your feet. That said, if a 25 cent piece required wading into some brush, you would probably just leave it be. But you would almost certainly walk a few feet into the weeds if you saw a $10 bill caught in some brambles.

Let’s look both at proximity and profit a bit more closely.

Proximity

Prospecting for trout is a precision approach. Not for naught do guides like to instruct prospecting anglers to “rub the fly” against wood, or tickle bankside vegetation, when targeting likely lies. When prospecting, we are trying to get close to the fish so it doesn’t have to expend too much energy to eat. But the only proximity we can achieve is on a horizontal axis—unlike when fishing streamers and nymphs, which also allow the angler to get close to fish on a vertical axis.

Proximity on the horizontal plane is important because the fish we are targeting while prospecting may well have to move a few feet vertically, even if we place the fly right above their head. This is one way in which the fish we prospect to are different from actively rising fish. A trout that is actively rising to insects has already been convinced by the sheer abundance of bugs to take up a favorable feeding position, generally relocating closer to the surface or at least occupying a hydraulic situation that makes moving to the surface efficient. The trout we are targeting as a prospecting angler, however, are likely to be holding deeper and closer to cover or structure. Because the dry fly angler cannot move any closer to fish on a vertical axis, they must do their best work on getting close horizontally.

Profit

Profit in the trout’s case simply means eating more calories than are expended. This means that a trout sitting at the bottom of a pool in good flow is not going to enjoy any caloric profit by rising to a size 20 blue-winged olive. Quite the contrary: it would be embracing a caloric deficit. This is why, when prospecting, we tend to try to imitate the largest offerings that are generally available at a given time of year. We also can size up our bugs when fishing over deeper water.

An exception to this “bigger is better” idea when prospecting comes on highly pressured water. In this case, you might go the opposite direction, that is, to use slightly smaller and subtler versions of popular local search patterns. If fish are getting hammered with aggressively dressed, size 8 stonefly imitations, a small and subtler stonefly version might be worth throwing, especially if you are not the first person on the water that day.

What Makes a Good Prospecting Fly

The right flies for this approach

The prospecting angler considers their fly box from a very different point of view compared to the hatch-matching angler. Since fish are not selective to in-the-film emergers and spent patterns, angler can fish high-floating flies that present a strong visual to fish. Let’s look at the floatability and shape of prospecting flies separately.

Floatability

As we’ve established, selectivity is a function of availability. And because the prospecting angler is generally fishing when there are only sparse bugs on the water, or none at all, opportunistic fish are not overly selective fish. Therefore, the prospecting angler isn’t tasked with imitating a nymphal shuck or having a perfectly proportioned spinner. This means that prospecting anglers can embrace high-floating patterns built with plenty of hydrophobic material—the last thing we want while searching for trout is to constantly reapply floatant.

A close cousin to floatability is skatability or twitchability. That’s because occasional, deliberate movement is one of the tricks a prospecting angler has to entice interest from nearby trout that are not actively feeding. The ability to skate a fly generally comes from a densely hackled patterns like Stimulators and elk hair caddis, but most any pattern can be made to skate better by wrapping the body of the pattern in dense, undersized hackle—even mayfly spinners make good twitch flies when dressed this way. .

Shape

Most prospecting is done with flies that passably resemble something in the watershed, both in terms of size and silhouette, though both are sometimes slightly exaggerated to more clearly telegraph to a trout several feet of water away: this is food and food worth moving for.

Because fish are not comparing your fly to thousands of naturals, which makes any minor difference stand out, imitative prospecting flies are often a little chunkier than the natural and often flashier with some tinsel or buggier in the form of rubber legs. This exaggeration of natural characteristics could be very problematic for the hatch-matching angler fishing a dense hatch where the trout has clear and abundant reference points and can easily discern that “one fly is not like the other,” but this discernment is compromised when a fish sees a lone bug drifting several feet above them.

Imitative vs. attractor patterns

While most attractor patterns resemble an insect native to the watershed, which we’ll call imitative patterns, we also have another category of prospecting fly that we refer to as attractor patterns. These are flies that usually share a silhouette with the natural but possess other features that are definitely out of this world. One well-known attractor is the Royal Wulff, which features an iridescent peacock herl body and blood-red band dividing the body.

Attractor patterns are part of the deep mystery of fly fishing—why some colors, textures, and shapes that never appear in the trout’s purview nonetheless can be very effective. And what constitutes an effective attractor pattern flies vary by region and even river. What works like magic in one place may not work well in another. Here, fish respond positively to a red grasshopper. There, a purple-bodied mayfly wins the day. All in all, attractor patterns are a lot of fun to fish, particularly on days when nothing else seems to work. Come to think of it, it was probably to find success during slow days on that water that attractor patterns were born in the first place .

Dry and Dropper

The Dry and Dropper approach is a great exploratory tool that can help anglers more quickly divine what fish want to eat and where. While a dropper can be any fly, including another dry fly (as we’ll discuss in “Targeting Riseforms”) most of the time the term “Dry and Dropper” refers to a high-riding dry fly and a weighted nymph, where the dry fly does double duty as a strike indicator.

When rigging a dry and dropper, the length of the leader tends to be a little shorter than when fishing a dry fly alone—this is to accommodate the extra material in the form of the dropper. Also, tippet tends to be at the thicker end of the acceptable spectrum to help with the manageability of the rig while casting.

Fishing a dry and dropper really opens up opportunity, since you can target active and passive fish at the same time, and fish classic nymph water as well as classic dry fly water without changing flies or leaders. To rig a dry and dropper, take a lightly or moderately weighted nymph and attach it to the bend of the hook of the dry fly via a length of tippet. How much distance you’ll want between your dry and dropper is up to you. You fish a fixed length all day long, or constantly change tippet length as the water depth you’re targeting changes. For the latter angler, pre-rigging nymphs with various tippet lengths on rigging foam can make changing out nymphs of different weights tippet lengths less tedious. You can even leave your knots incomplete/unseated so that all you need to do is slip a loop over the hook of the dry fly, moisten and seat the knot, trim the tag end, and voila—you’re back fishing with a new dropper.