Trout Flies
by James Marsh
Copyright 2018 James Marsh
Fishing Journal
February, 2018 Issue
Chris Tobias fishing the South Holston
If you plan on fly fishing almost any trout stream that you are not familiar with, say the XYZ river,  you better get used to
reading and hearing about “XYZ trout flies“. Although the name infers there’s something unique to the XYZ river about the
flies you need to fish, there isn’t anything unique or otherwise special about them.

The purpose of the fly is to fool the trout into taking it for one of the insects, or other items of food, the trout are eating at the
time. If the fly does a good job of that, there won’t be anything unique to that river about it. The insects and other trout foods
that exist in the stream of are found in many other streams. There will always be several species of aquatic and terrestrial
insects found in the XYZ stream, that exist in trout streams throughout the nation. The same thing will be true of most of the
baitfish, minnows, sculpin, and crustaceans that are in new stream you are about to fish.  

It is a fact that some streams and lakes have many books and articles available about the aquatic insects and other trout
foods that exist in the stream and others don’t. Some of the books and articles list and describe the insects and other foods
accurately and others don’t. Some magazine articles, websites and books list certain flies rather than the insects or other
foods. Flies are not insects, or any other type of trout food. They are hooks with hair, feathers and other items tied on them.
Trout don’t eat hair and feathers. They eat real insects and other foods that are available in the water they live in.

The various foods the trout eat aren’t unique to any particular stream, and neither are the flies you need to imitate them to
catch the trout. The only thing that should be unique about the flies is they should imitate the specific insects and other
foods the trout eat in the particular stream you want to fish. The more your fly resembles the appearance and behavior of
the most plentiful and available food the trout are eating in that stream at the time you will be fishing, the easier it will be for
you to fool the trout into taking your fly for the real thing.

You’ll probably read and hear that the presentation of the fly is far more important than the fly itself. It’s a talking point some
anglers frequently use as a cover up for their lack of knowledge about the aquatic insects in the streams of the Smoky
Mountains. To say the presentation of a fly is more important than the fly itself is like saying the engines of an airplane are
more important than its wings.

There is another important thing The trout in Great Smoky Mountains National Park are wild, stream-bred trout. They are
not stocked trout that were raised in a hatchery on fish food pellets. One reason they
survive as well as they do is they are extremely skillful at avoiding predators. The trout
are as nervous as a long tail cat in a nursing home room full of rocking chairs. They
survive their entire life by eating the food that’s in the streams they live in but only when
their pea size brains signal they are safe from being eaten by one of their own predators.
If you want to be successful in catching them, you better make certain your fly is the only
thing they see. If they see you, your shiny fly reel, or even the shadow of your fly rod
waving through the air, you can forget about catching them. Just the sight or sound of
your fly line hitting the water is enough to send them fleeing for the nearest cover.
Since the fly represents what the trout are trying to eat and since it’s the only thing the
trout should be able to see to avoid spooking them before they are hooked, don’t you
think it’s rather important? Furthermore, doesn’t it makes sense the fly should resemble
the same thing the trout are eating?

Wherever you fish, get used to hearing that trout feed opportunistically, a tongue twisting statement often used by bug
challenged anglers to lessen the importance of the fly. It is a true statement because it can be said that trout feed
opportunistically everywhere they exist. In a technical sense, all fish are opportunistic feeders. That simply means if it's
available, they may eat more than one single item of food. This particular one word oversimplification of how trout feed can
create big problems for those that misunderstand it. The fact trout feed opportunistically is often misinterpreted to mean the
trout will eat whatever happens to come along and that the particular fly you use isn't important.

Selective feeding is another little understood fly fishing term that’s often interpreted to mean just the opposite of
opportunistic feeding. A trout is said to be feeding selectively when it's preferring one insect over another. In a pure technical
sense, if a trout ate a hundred Little Yellow stonefly nymphs and just one Light Cahill mayfly nymph, it could be said the trout
was feeding opportunistically. From the same technical standpoint, the trout would not be feeding entirely selectively
because it ate more than one insect. If selective feeding is used in a more meaningful sense it would imply that even though
trout may not focus entirely on one insect, the great majority of what they eat is always the one that’s most plentiful and
easiest for them to acquire.

If a trout is feeding near or on the surface in a certain area, feeding lane or zone of water, and both a Mahogany Dun and a
Blue-winged Olive dun happened to be drift downstream, side-by-side within that zone, the trout may very well eat either one
of the insects. If it could react quickly enough it may even eat both of them. It may not feed selectively in the sense it would
choose one insect over the other. The problem with this hypothetical scenario is that it's unrealistic. Such a scenario rarely
exist in most trout streams and lakes. During the times trout are lined up in a particular  lane, line or zone of water feeding on
the surface in a fast water riffle or run, they are there because of a concentration of food. This food almost always consists
of one and only one insect. It’s rare that two or more different aquatic insects are hatching at the same time and are getting
caught up in the fast water current seams together.
??? Duns are crawler nymphs that prefer fast water and Blue-winged Olives are
swimming nymphs that prefer slow to moderate flows. They neither live nor hatch in the
same areas of the streams. They rarely get caught in the same currents and almost never
at the same time.

Even though much of the water in the high gradient streams is fast flowing water, most likely, less than a third of all aquatic
insects that exist in the stream hatch in areas where they can easily get caught in the fast water. Most of them are able to
emerge and fly away from slow or moderate areas of flow.

About a third of the aquatic insects, including some mayflies, several caddisflies and all stoneflies, don’t hatch in the water.
They crawl out on the banks to hatch. Trout focus on eating them when they crawl out of their normal hiding spots beneath
the rocks to the banks. Those hatching insects that do get caught in fast water are almost always clinger mayflies. Although
they move from their normal fast water habitat to the nearest slower flowing water to emerge, many get caught in the seams
between the slow and fast water and channeled downstream in the fast water. This feeding zone, area or lane I'm referring
to, whether it is in fast, moderate or slow areas of water, also relates to depth. It includes the surface and the column of
water from the surface to the bottom as well as the bottom itself.

Although you may envision various nymphs, larvae and other food drifting downstream at random, whether accidentally or in
a behavioral drift, such a situation very rarely exist. Aquatic insect nymphs and larvae don't survive drifting freely
downstream. Except during a hatch, there's almost never enough free drifting nymphs, larvae, terrestrial insects ,or any
other form of food in the fast water at any one time to warrant trout holding in the faster currents to feed. When trout are
feeding in certain areas, zones or lanes, they are almost always feeding on one particular insect that’s hatching in quantities
sufficient enough to warrant the trout being there holding in the fast water feeding on them. Anytime there’s lots of food
drifting downstream in fast water current, you can bet you last dollar there's a hatch underway. Trout won't hold in fast
current waiting on random bits of food to drift downstream. If they did, they will expend more energy than they could
replenish.

The exact location of whatever is most available and most plentiful for the trout to eat in a stream at any given time varies
greatly. The different aquatic insects live, feed, hatch, mate and fall dead in different sections and depths of the streams
depending on the particular species of aquatic insect. Even if the trout aren’t being one-hundred percent selective as to the
particular food they are eating, they are certainly being selective as to exactly where in the stream they are looking for food.
Selective feeding is nature's way of letting the trout feed efficiently. This allows them to use less energy and take in more
food. The trout are feeding in similar areas of the stream, focusing on eating what’s most plentiful and available for
them to eat using a minimum amount of effort. It’s necessary for their survival. If trout expend more energy than the food they
take in can replenish, they will soon die.Trout will only get into a certain fast water feeding zone, line or lane and hold there
only when there's a substantial amount of food coming their way. As long as there's an adequate amount of food coming
down the same feeding lane, the trout won't move to another area of water, or seek another depth to feed. Again, in such
cases, it's almost always one and only one insect.

Why do certain generic flies that mimic several insects of the same size and general shade of color sometimes work quite
well in the fast water and why do attractor flies that don't necessarily match anything often work in the fast water? For
example, trout will sometimes take a gray body Parachute Adams dry fly when yellow Light Cahills are hatching. The answer
lies in timing. First of all, a trout has only a fraction of a second to examine a fly in fast water. Secondly, the trout has only a
small window of vision when it is feeding near the surface. The trout is only able to see a distorted image of part of the
fly that's above the surface and only for a split second. Even then you will often see flashes where trout detect something
that’s unnatural and rejected the fly at the last split
second.
Even when an insect is hatching and becoming caught up in the fast water runs and riffles and trout are feeding on them,
which had you rather have tied on - a fly that imitated the hatching insect, or one that imitated something that wasn't even
present? Or had you rather have a generic fly that imitates a little of everything as opposed to a fly that’s imitating the insect
that’s hatching. Even in fast water situations such as I just described, you will find better, more realistic imitations of the
naturals results in a higher percentage of hookups.

What about those other two-thirds of the insects that either emerge or crawl out of the •  water to hatch from the slow to
moderate sections of the pocket water streams? In those cases the trout are able to get a very good look at your fly. In those
situations I think you will find that an imitation that closely resembles the appearance and behavior of the natural will greatly
increase your odds of success.

Please don’t refer to this solely as “matching the hatch”. It involves much more than that. It’s also matching the 99.9 percent
of the aquatic life in the streams that hasn‘t yet hatched. It should also mean “matching the egg layers”. It should even
include “matching the dead”, or the mayfly spinners and other aquatic and terrestrial insects that fall into the streams and
die. Don’t forget the other trout foods. Call that “matching the sculpin and minnows” if you like. Instead of improperly calling
everything “matching the hatch“, just call it “matching the naturals“. Even better, just think of it as matching the food the trout
eat with a fly that closely resembles that particular food‘s appearance and behavior.

Don’t think I’m attempting to undermine the importance of presentation, or that I’m even contending that the fly is more
important than the way it’s presented. That’s not my intension at all but do keep this in mind. The first and foremost important
key to presentation is knowing "where" in the streams the insects live and hatch. Remember, although the trout may not be
feeding selectively, eating one and only one insect, they are always selective in exactly where they feed. They feed where
the insects are most plentiful and easiest to acquire and that often isn't in the fast water where the trout are easier to fool.

If your not satisfied with mediocre success, or you do okay and you want to improve to the point you will be able to
consistently catch trout from the streams of the Smokies, I suggest you start by learning all you can about the food they eat
to survive on. If you have been fishing using the traditional generic and attractor flies like the Royal Wulffs, Parachute
Adams, Hares Ear nymphs and other generic and attractor flies, and your not achieving the success that you desire, you
may want to consider switching to more realistic imitations of the insects and other foods the trout eat.