Fly Fisherman Throwback: Terrestrials and Limestone Trout

Editor's note: Flyfisherman.com will periodically be posting articles written and published before the Internet, from the Fly Fisherman magazine print archives. The wit and wisdom from legendary fly-fishing writers like Ernest Schwiebert, Gary LaFontaine, Lefty Kreh, Robert Traver, Gary Borger, Joan & Lee Wulff, John Gierach, Vince Marinaro, Doug Swisher & Carl Richards, Nick Lyons, and many more deserve a second life. These articles are reprinted here exactly as published in their day and may contain information, philosophies, or language that reveals a different time and age. This should be used for historical purposes only.

This article originally appeared in the July 1983 issue of Fly Fisherman magazine. Click here for a PDF of the print version of "Terrestrials and Limestone Trout."

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Pennsylvania's limestone streams were the inspiration for some of the greatest books on American trout fishing, spilling classic angling literature from the minds of their devotees just as the streams pour forth from their subterranean sources as natural artwork.

They are home to enormous trout. Brookies measured by the pound rather than the inch. Browns topping 16 pounds. A 10-pound 11¼-ounce state record rainbow.

They are among the most fertile waters in the world. Their temperatures remain in the 50- to 60-degree range for 365 days of the year. The volume of flow does not rise and fall dramatically with the abundance or scarcity of rains, but remains relatively constant year around. The rich, alkaline currents support amazing food supplies up to 20 times greater than that of a freestone stream.

Rather than gathering flow gradually over their courses as they expand from tiny trickles to broad rivers, the limestone creeks emerge from their underground sources as full-bodied streams. They are, as Theodore Gordon succinctly put it, “great springs which gush from the rocks in large volume.”

“Dozens” of limestone spring creeks have been identified in Pennsylvania, according to Robert Hesser, former chief of the Fisheries Management Section of the Pennsylvania Fish Commission. Many of them have become household words among fly fishermen because of the rich angling they provide. The names read like a roll call of famous eastern trout waters: Big Spring Creek, Letort Spring Run, Falling Spring Branch, the Yellow Breeches, Green Spring Creek.

But as Hesser points out, these are just "the more famous limestoners. There are other significant streams. Spruce Creek in Huntingdon and Blair counties, Fishing Creek in Centre and Clinton counties, and Penns Creek, flowing through several counties, are three of the best in the state. Other fine limestoners are the Monocacy and Bushkill creeks in Northampton County, Little Lehigh River in Lehigh County, Spring Creek and Logan Branch in Centre County, Little Juniata River in Blair and Huntingdon counties and Clover and Piney creeks in Blair County." The locations of these fertile spring creeks, says Hesser, follow the fingers of limestone strata that extend through the central part of the state in a southwest to northeast direction, just as the mountains do. “The area roughly takes the shape of a parallelogram, extending from Bedford County to Centre County, then across to Nonhampton County and southwest to York County. All of these valleys do not contain limestone streams, but many do." Notwithstanding the cornucopia of angling literature these waters have spawned, the limestone streams demand a fresh look today. There have been changes, some of them drastic, over the three decades since the major works on this area were written.

New Strategies

I first fished the limestone streams of Pennsylvania in the 1960s. Even then, the waters were quite different from the hallowed spring creeks I had read about in the works of Marinaro and Fox. Since that time, more changes even have taken place.

Fishing pressure has increased. Different trout species and strains now inhabit some of the streams. Stocking has been eliminated on many of the better spring creeks. Pollution has increased. Streams have widened and silted, then narrowed and cleansed as reclamation work has taken place. Regulations on creeling trout have been tightened drastically (many are now catch-and-release waters.) On the hallowed Letort a devastating, but not fatal, fish kill occurred. And on many of the streams, striking shifts in the diet of the trout have transpired.

The changes could be the subject of an extensive article unto themselves. But for now, let's concentrate on taking a new look at strategies and tactics for fishing the limestone creeks.

A number of methods can be productive on these challenging waters. You can fish with big, weighted sculpins on thick tippets, plying stygian holes. You can sight cast to "rooters" burrowing in the aquatic vegetation for sow bugs and scuds, especially on Big Spring and the Letort. Or you can concentrate on the few good hatches that continue to emerge on these alkaline waters. But for day-in, day-out sport–on the surface, where many of us feel trout fishing is at its finest–no offerings can compare with the terrestrials for the limestone creeks.

The importance of terrestrial insects in the diet of American trout was first recognized by Vincent Marinaro and Charles Fox on these very waters, and detailed in their books A Modern Dry Fly Code and This Wonderful World of Trout. Since these works were published, the few hatches of aquatics the streams did produce have dwindled, and the importance of land insects in the diet of the trout has increased many fold. This is a trend that is widespread throughout the country, in both limestone and freestone streams alike.

While populations of delicate mayflies wane in response to development and stream degradation, hardy terrestrial insects hold their own or increase in numbers. The land insects seem to be constructed from the bottom up for endurance. The beetle is a prime example: squat, tanklike in build, beetles are custom-made for survival. Some can eat arsenic without being affected. Other beetles can gnaw through thick electrical cables. One scientist, intrigued by the strength of these creatures, placed tiny bags of shot on a beetle's back. The insect was able to carry 270 times its own weight! An oddity perhaps, but such a feat is indicative of the tremendous durability of the terrestrials. This is one surface food trout and trout fishermen can count on being around for many years to come.

Some 1,500 species of mayflies have been identified, compared with one million terrestrials. The Coleoptera (beetle) order alone contains some 300,000 separate varieties.

Though they spend no part of their lives purposefully in water, these land insects manage accidentally to enter trout streams by the thousands over the course of a day. Wind, rain, a careless leap, chasing predators and mating flights send countless land insects into the limestone streams. Once they enter the stream, very few escape the great surface tension between water and air. It acts like a fly trap, clutching the insects in its grasp and preventing escape by all but a lucky few crickets and leafhoppers that occasionally are able to scramble back onto land. To free itself from the stream's surface film, a typical land insect, such as an ant, must drag with it more than its own weight in water when leaving, due to its high ratio of surface area to weight. A fisherman, on the other hand, carries only about a pound or so of water on his body when he leaves the stream, or about one percent of his weight, compared with 100 percent for the ant.

When trout detect these protein-rich insects struggling helplessly on the surface film, they move in for the kill. The fish sense an easy mark and a quick way to fill their bellies. While it’s true that the fish seldom see land insects in the concentrations that they see specific aquatic insects during a heavy hatch, they do see enough of them to learn quickly that these creatures are a prime food source.

Mayfly Bias

Ironically, even though this was the birthplace of American terrestrial fishing, the quality angling available with land-based fly patterns on the limestone streams attracts comparatively few fishermen. Visit Falling Spring Branch on a summer morning and you will have to cope with mini-traffic jams as swarms of anglers vie for choice spots to cast over fish feeding on Tricorythodes spinners. But at noon, as the last of the spinners fall spent to the silver spring and the trout begin to rise less frenetically, it is as if someone blew a whistle signaling the end of a factory work shift. The anglers pack up their reels, case their rods, plop themselves in their cars and zoom away. To most, the end of the hatch marks the end of good fishing for the day. A similar scenario repeats itself on Yellow Breeches Creek, on the long, slow milky pool above the Allenberry Inn. Only in this case, the timing is reversed. Walk softly along this pastoral creek during the morning or on a summer's afternoon and you will see fish after fish lined up along shore, shoulder to shoulder. They are feeding; slowly, leisurely sipping down terrestrials.

But where are the anglers? There are none, or precious few. They are biding their time, waiting for the brief flurry of hectic paced rising that will transpire when the famed Ephoron leukon "white fly" hatches just at dark. Then they will come out like fireflies at dusk, crowding elbow-to-elbow to fish "the hatch." True, that is an exciting period to fish. But what do they land during that hour-long period when these pale duns emerge? Perhaps three, four fish. A very good angler may take half a dozen. A terrestrial fisherman working these same waters during the day can easily take several dozen trout. I've done it numerous times. There are many more skilled fishermen than I who could probably take twice this number of fish by focusing on the daytime terrestrial-feeding fish.

Because so many anglers forgo this rich midday sport, the angler on Falling Spring, on the Breeches and on other limestone streams in Pennsylvania enjoys one additional benefit: solitude astream. It is a precious quality in these crowded times we live in.

Another plus of fishing the limestone streams with terrestrials is the relaxed pace and tone of the sport. The crystalline streams inhabited by finicky wild and holdover trout are difficult enough to fish when one can be relaxed. Add the tension of a heavy mayfly hatch, when we tend to get tightened up like overwound alarm clocks, and there's almost too much pressure to enjoy ourselves fully. We know we must cram in as many casts as we can, as quickly as possible before the hatch peters out. We seem to take our key from the trout, whose frenzied feeding during a short-lived hatch excites us as well.

Terrestrials, on the other hand, offer a slower, more relaxed way to fish the limestone creeks. There's no brief hatch that's destined to end any minute. The land insects dribble in continuously over the entire day. We can take our time with each fish, work on him at our leisure, relish the moment.

Most fly fishing can be broken down into three distinct phases, all of which can influence the success or failure of our effort. These include fly choice, approach to the fish, and presentation of the offering.

Trout literature in the last decade or two has overwhelmingly stressed one of these three ingredients: fly choice. The work has involved intense concentration on species and even sub-species identification of mayflies and caddis, and an equally prodigious effort to duplicate exactly the appearance to the trout of each one of these species. Since the emphasis of these works has been on fishing for trout during heavy aquatic hatches, this preoccupation with fly choice is understandable. When feeding on a dense flotilla of duns or spinners drifting on the current, trout temporarily lose much of their wariness. How we approach the fish and present the fly become less important than the pattern we use. Trout feeding on a heavy hatch sometimes can be approached almost boldly on many streams and have flies. delivered to them with less than the utmost finesse and still be taken if we use the right imitation.

When fishing terrestrials for limestone trout, the situation is far different. No longer can we walk right up to the edge of the stream with impunity. No longer can we cast sloppily, figuring the fish is so consumed with feeding on one certain abundant insect that it won't be put down, or will resume feeding again quickly if it is.

On the contrary, with terrestrials approach and presentation become the two paramount concerns of the fly fisherman. Fly choice becomes the least important factor. With no aquatic insect blanketing the surface, trout of the spring creeks become wary and circumspect. A heavy footfall or a flash of rod overhead can spell disaster for the angler.

Fly choice is still important when fishing terrestrials. It just does not possess the exalted status it does during a heavy hatch of an aquatic insect. Some of the variables that will influence which land insect pattern to choose include the nature of the streamside habitat, season, time of day, variety of insects active on land or present in the water, whether the trout are rising or not, the nature of their riseforms, size of fish, where they're positioned in the stream and past experiences on a particular stretch of water. There are many variables involved in this puzzle of choosing the best fly. But fortunately, in terrestrial fishing we are seldom faced with a setup where only one fly will work. Typically, there will be several patterns that will take trout on a given day. Exclusive selectivity, where a fish feeds on one specific insect to the exclusion of all others, is a luxury the trout usually can't afford, even on fertile limestone streams. Unless they are primarily subsurface feeders, they'll sip in an ant; then a beetle, then a leafhopper or true bug randomly, as the insects drift down to them in a mixture. Food in the stomach is the name of the game. The trout that eats the most insects is the one that grows the quickest and survives the longest.

Fly Selection

There are two theories on how to handle terrestrial fly choice for the limestone streams. One is to pick a fly that you think is best for the given season, time of day and stretch of water, then stick with it, presenting the offering to as many fish as possible. The other theory is to find a fish and switch flies until you unlock the combination to that trout's jaws. I like to steer a middle course, not becoming obsessed with catching one individual fish (unless it’s a brute), but not skipping over trout just because the first terrestrial I present doesn't do the trick. A large variety of terrestrial patterns is available today, but for fishing Pennsylvania's limestone streams, you can stock fewer than a dozen varieties and should be able to take just about any fish willing to rise from spring through fall.

Ants top any list of terrestrials for the limestone waters. If ever I were forced to choose one fly to fish for trout for the rest of my life, this would be it. I stock a variety of ants in my fly boxes. The basic fur ant, tied of rabbit or seal fur or a synthetic, with two or three turns of hackle in the middle for legs, is a classic pattern. The fly was first tied by Bob McCafferty in the early 1930s. Today, in 1983, it's still a deadly offering for limestone trout. Fur ants will take trout on all waters, but I've enjoyed especially good results with them on Falling Spring Branch, the Letort, Little Lehigh, Big Spring Creek and Fisherman's Paradise on Spring Creek. Sizes #14-#22 ict black and #16-#24 in cinnamon or hot orange are the workhorse fur ants. One variety of this tie I like especially for finicky trout employs bent deer-hair fibers for legs, instead of hackle. Be sure to make a very prominent thin waist in tying your ant patterns, since this seems to be the key trout home in on when identifying these insects as a favorite food.

An excellent pattern that stresses this constriction of the waist is the McMurray Ant, invented and patented by Ed Sutryn, of McMurray, Pa. Ed ties this fly with two pieces of balsa or cork cylinder threaded on a section of monofilament. This assemblage is then tied to the hook and hackle wrapped on for legs. Sizes #14-#22 in black, brown and a combination of a black body and red head are productive on all of the limestone creeks that I've tried them on.

For those cherished occasions when a flight of mating ants takes place, usually in August or September on still, muggy days, stock a few winged ants in sizes #14-#22, in black and brown.

Beetles in deer hair and cork should be included in any limestone terrestrial selection. You can also add a few of the lightweight featherwing beetles that work well on the Letort and Big Spring. The Crowe Beetle, tied with an extra-large amount of clipped deer hair so it’s fat and rotund, and a simple spun and trimmed hair beetle are excellent in sizes #10-#16. Some of the largest browns and rainbows I’ve taken on limestone creeks have come to these patterns, which make effective imitations of the Japanese beetle and many other Coleoptera species. Cork beetles in sizes #12-#l8 have been exceptional producers on the Yellow Breeches and the Little Lehigh, but I’ve taken trout on many other limestone waters with these easy-to-make offerings. Black is the only color needed.

Caterpillars can be important during late spring and summer along forested stretches of streams such as Penns Creek, the Little Lehigh, Yellow Breeches and the Fisherman's Paradise. Tie them on 2X-4X long hooks, sizes #8-#16, using wrapped deer hair, spun and trimmed deer hair, a turkey quill section, or cork. Green, brown and gray are the most common colors.

Everyone has a favorite hopper pattern. Chances are it will do as well as the next fly when fish are feeding on the Orthoptera during spring, summer and fall months. I've had good luck with Dave's Hopper, Joe's Hopper, the Letort Hopper and occasionally with cork grasshopper flies. Sizes #10-#16 are useful on the limestone creeks.

Some of the best hopper fishing takes place when the immature insects are prevalent during late spring and early summer. The insect in this stage of growth does not have wings, but the legs are quite prominent. A pattern I developed for this fishing, called the nymph hopper, consists of a thick rabbit-fur body with two small bunches of deer hair extending from the middle of each side for legs. Tied on #14 and #16 hooks, in grayish-brown, greenish-brown, and dirty-yellow, this fly works very well when trout are feeding on the nymphal grasshopper stage on the limestone creeks.

Two cricket patterns work especially well on these waters. Sometimes they even account for enormous browns in the five- to eight-pound range. Al's Hair Cricket was devised by Al Troth; the Letort Cricket was created by Ed Shenk, late in the summer of 1959. These flies work especially well at dawn and dusk, when swirls of white mist rise from the water and the furtive naturals fill the air with their steely chirping. Sizes #10-#16 are best during the day. At night you can go to #6 and #8 for jumbo browns. August, September and October are the best months for cricket fishing.

A jassid or leafhopper, #18-#22, with palmered and clipped hackle and an overlaid wing of jungle-cock eye or substitute feather, is an extremely effective pattern and should be in every limestoner's fly box. Use brown, black or blue dun hackle and clip a v-wedge on the bottom and top.

One final fly that sees occasional duty on the limestone creeks in fall is a cork or deer-hair bee pattern, #8-#12. This fly imitates the yellow jackets that become so abundant in autumn. It’s especially useful on forested stretches of water.

Granted, there are many other important terrestrial foods for trout, such as true bugs, moths, treehoppers, cicadas and the like. But the angler who carries fishable, realistic imitations of the ants and bees, beetles, grasshoppers and crickets, caterpillars, and leafhoppers will be well equipped for catching trout on the surface on limestone streams virtually anytime from spring through fall, whenever there is not a dense aquatic hatch in progress.

Approaching Limestone Trout with Terrestrials

Approach the second main ingredient in a fly fishing strategy, is often critical on the limestone streams. This is doubly true when fishing terrestrials. There's no heavy hatch to lower the trout's guard. The waters are glass clear. Most of the fish are skittish stream-bred trout. Since so many earth insects tumble into the stream directly from the banks, a lot of this fishing is also done in thin, difficult water near shore, where trout lie in wait for the terrestrials.

Lumber crudely up to the stream and all you're likely to see is v-wakes slicing through the water as fish flee for cover. Instead, one must approach these terrestrial-feeding limestone trout as warily as if he were stalking a keen-eyed antelope on the open sage flats of Wyoming. Whenever possible, stay out of their sight plane. If you must enter it, keep your movements soft and fluid, rod motion low. The best limestone fishermen spend much of their time hunched over, sometimes even down on their hands and knees. It's more punishing physically to spend half or more of the day in these convoluted postures as you stalk trout, but the results are well worth the extra effort.

Each limestone stream's inhabitants seem to have a slightly different “safety zone.” If they see an angler inside that zone, they'll either spook or simply stop feeding while remaining in sight, tempting us with their presence, but refusing to eat. This safety zone is perhaps widest of all on the Letort which must have some of the most spooky trout in the world. Big Spring Creek and Falling Spring Branch vie for a close second.

All three streams, as one would expect, are inhabited solely by wild, stream-bred fish–the most skittish of all trout.

On waters such as the Little Lehigh, Fisherman's Paradise and Yellow Breeches an angler can approach the quarry much closer with impunity, since he's dealing mostly with hatchery-reared fish. But even these trout have their safety zones, narrow though they may be. If you break into that zone with a sharp movement, they'll either spook or cease feeding.

Rules of thumb for approach to limestone trout, then, are to first spot your quarry from a distance, so you don't scare it before the game even starts. Then ease slowly and stealthily into casting range, keeping a low, crouched profile. Drab clothing–olives, grays, tans, even camouflage–also helps.

Presentation to Limestone Trout with Terrestrials

Presentation is the third, and often most important phase of terrestrial fishing on limestone creeks. For practical purposes, terrestrial angling can be broken down into two categories: fishing with big, heavy flies and small light ones. Included in the first group would be large beetles, crickets, grasshoppers, caterpillars, moths and bees, plus certain true bugs. In the second category come such featherweight creatures as leafhoppers, treehoppers, small ants and light, small beetles.

The important difference between these two groups is not a scientific one of species, family or order. Rather, it's strictly a fisherman's pragmatic division based on the way the insects enter the stream. Since none of the land insects naturally inhabits the water, their entrance into the stream is often a vital key used by the trout in feeding.

Small, light insects such as leafhoppers and ants blow into the spring creeks like a fluff of dandelion. They seldom make enough noise or impact to draw the attention of the trout. Because of this, the fish uses sight as its primary sense when·feeding on these bantamweight insects.

We can take our clue from this and present these offerings above the fish, in standard dry-fly fashion–as delicately as possible. The fly is then drifted over the trout, without drag. Long, fine leaders are required, and smooth, subtle casts. This terrestrial fishing with tiny patterns is most useful when you see trout daintily rising to what looks like absolutely nothing, and when no large terrestrials are in evidence on the water or along the banks. This is one of my favorite types of terrestrial fishing, and I particularly like this approach for the Letort and Falling Spring Branch. Some of my most memorable experiences with the tiny, lightweight terrestrials have been on Fisherman's Paradise stretch of Spring Creek and Little Lehigh, though. Here, on a summer's day, you'll find dozens of trout lined up along the banks, eager to sip in a #22 or #24 cinnamon ant presented delicately above them. Catches of 25 or 30 fish in a day can be common.

The other kind of terrestrial fishing is equally fascinating, but quite different in theory and execution. This is fishing with the big, heavy patterns that imitate beetles, hoppers, crickets, caterpillars and bees. Whenever you find a reasonable number of such hefty critters on the ground along the stream or in nearby trees or shrubbery, this fishing method is likely to produce. Seeing sporadic, loud, boiling rises is another tipoff that the trout are sucking in stray heavyweights that stumble in from land.

These insects are large, dense and make a distinct splat when they descend onto the water. Trout use this sound as a key in their feeding when big land insects are entering the limestone streams. The fish will investigate almost any surface disturbance at these times, since it may be a tipoff that a juicy tidbit has fallen into the water from land, and there's a free meal floundering about for the taking.

It goes against all the training we've had that says fly fishing for trout is a graceful, gentle sport, but the angler who mimics this audible, clumsy entrance of the big terrestrials is in for some superb fishing on the limestone waters. The way to do this is to drop the fly to the surface with a light splat. To accomplish this, use heavy flies made of deer hair, cork or quill and put just a little extra push in the final forward delivery stroke. You don't want the leader or line to come slapping down, but the fly should make a distinct plop as it strikes the stream's surface. If a trout is within range where he can sense the entrance of the fraud, a charging strike is likely. I've had browns surge 10 feet to intercept such offerings delivered with a plopping noise. Sometimes they'll refuse when they finally arrive and examine it. More often, the jaws will clamp down viciously, with the fish acting more like a bigmouth smashing a hair bug than a sophisticated limestone trout.

One trick that will increase takes when using the sound cast method is to drop the fly to the side or a few inches behind the fish's holding lie, rather than in front of it. This keeps your leader out of view of the trout and also takes him by surprise, causing a quick turnabout and an instinctive strike before his sense of caution prevails.

Trout in swift currents aren't as eager to turn and charge downstream to sip in a plopped terrestrial as fish in the slower, thin-water pools and flats. The best candidates of all are those close to shore, where beetles, true bugs and caterpillars tumble off of grasses and shrubbery. Here the trout are waiting for just such morsels to splat into their domain. I've had up to 75 strikes a day using this method on the Yellow Breeches, landing and releasing about half of those fish, missing the others. Big browns are often especially responsive to this novel delivery method.

Fish the hatches on the limestone streams when mayflies or caddis emerge in sufficient numbers to stimulate selective feeding. But when the hatch peters out or fails to materialize, don't assume that the fishing is over. Some of the finest sport of the day will just be getting under way for the angler who appreciates the important roll terrestrials play in the diet of limestone trout and knows how to fish these land-based imitations.

A Limestone Sampler

FALLING SPRING BRANCH: Franklin County, 1.75 miles of catch-and-release water from the T-515 bridge downstream to a wire fence crossing the Robert E. Gabler farm, about a quarter mile upstream from I-81. Take the Lincoln Way Exit at Chambersburg. Turn right off of PA Route 30 immediately onto first hard-surface road. The next three roads to the left from here all lead to the creek.

BIG SPRING CREEK: Cumberland County, L 1 miles; from 100 feet below the source (Big Spring) down to the Strohm Dam, two trout a day allowed, 15-inch minimum size limit. Take the Newville Exit, PA Route 233, off of I-81. Look for the PA Fish Commission sign on the right, just a couple miles down the road. A left turn here leads to the stream.

LETORT SPRING RUN: Cumberland County, 1.5 miles of catch-and-release water, from 300 yards above the bridge on T-481 down to the Reading Railroad Bridge at the south end of Letort Spring Park in Carlisle. To reach the upper water, take the Hanover St. Exit off of I-81, PA Route 34 South, at Carlisle. Drive south for less than one mile, then turn left on Bonnybrook Road, which leads to the spring.

YELLOW BREECHES CREEK: Cumberland County, take PA Route 34 south from I-Si to PA Route 174. Go east here for four miles, just past the town of Boiling Springs, to Allenberry. This is the catch-and-release section. Other parts of the stream are accessible on PA Routes 174, 233, 34 and 75.

PENNS CREEK: Mifflin and Union counties, 3.9 miles of catch-and-release fishing from Swift Run in Mifflin County down to R.J. Soper property line in Union County.

SPRING CREEK: Centre County, the famed Fisherman's. Paradise, 1.6 miles from the lower boundary of Spring Creek Hatchery to the upper boundary of the Paradise. Catch-and-release fishing.

LITTLE LEHIGH: Lehigh County, one-half mile of catch and release fishing from Prices Bridge to a point south of Hatchery Road Bridge. To reach this stretch, take Fish Hatchery Road off of PA Route 29, also called Cedar Crest Blvd.

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Gerald Almy, author of Tying & Fishing Terrestrials, lives in Woodstock, Va.

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