Eye of the Guide


Tom Travis - Aug 12, 2013

"One cannot consider any aspect of fly dressing, whether it be fish vision, mechanics or anything else, in isolation; all are so entwined that any attempt to separate them can only be false."
Fluorescent Flies, Joseph Keen 1964

Almost from the very beginning fly anglers have spent much debating the importance of the color, size and shape of the artificial fly. Some believe shape and size are the most important and that color is the least of the important factors in the design of an effective imitation.

Every angler who ties artificial flies has their own beliefs on the subject and often has countless stories to support their stance on this subject. However I believe in approaching such a heavy subject based on research and countless hours of on stream observation and a heavy dose of common sense. Sometimes when we tackle a fly fishing or fly tying problem we tend to focus on one or two disciples such as research to include scientific data and the writing of others and therefore often tend to form opinions without completing the research and without apply good old fashion common sense.

Therefore I have determined to put down my thoughts on this subject and hopefully I will do so in manner that may help those individual who are still confused on this issue.

I have read countless pages covering this subject and have listened too many explain their views on this subject and there are many diverse opinions and many examples to back up their position on this subject. Often the type water being fished becomes a key factor in their beliefs.

However I believe that color, size and shape are all important and equally so furthermore I would add one addition element which I believe is critical to designing effective imitations and that is the illusion of life.

We are not one hundred percent sure of how trout actually see or exactly how they view colors. Furthermore we will not know the answers to these questions until we find that remarkable talking trout. Any ideas, speculations and theories put forth, including those that I present are exactly that theories and speculations!

However based on the physical evidence and observation we can make a few common sense assumptions which are hard to dispute. The fact of the matter is that we know from the physical evidence how the eye of the trout is constructed and when compared to the eyes of other organisms including the human eye there are a great many similarities. The scientific data on these similarities are fact and I could spend time laying out this evidence which would take many pages. However I fear that many would find this boring and soon fall asleep. Therefore I will offer a diagram of the trout's eyes which is labeled to the critical aspects of the eye.

Diagram of the trout eye – Illustration by Rod Beland

In all of the discussion on how the trout see color one important fact is often overlooked, in his 1964 publication entitled Fluorescent Flies Joseph Keen makes a rather astute comment in regards to color and how the trout see.

"If a trout could see as well as its eyes are equipped to see it would surely be no more likely to mistake an artificial fly for a natural fly than would a man."

However Keen was well aware that what the trout can actually see is only part of the answer and the second part is how the brain interprets the signals that come from the eye of the trout. That brain function or lack thereof is the key to understanding much of the science of imitation and much else in the world of fly fishing.

Now there are two facts which we do know, first that trout see with light as most creatures do and secondly we know through observation, experience and vast amounts of historical data the trout eat artificial flies.

Let us explore the properties of color and the effect of light on color and how the ever changing light affects the feeding of the trout and those who tie imitations to deceive them.

The effects of light on vision and color is another factor that seems to confuse some, however the effect of light as related to the vision of the fish was well document of Colonel E. W. Harding in 1931 with the publication of The FlyFisher & The Trout's Point of View furthermore Harding's work was expanded on and brought up to date by John Goddard and Brian Clarke which the publication of their marvelous volume entitled The Trout and the Fly in 1980. This volume shows numerous well label diagrams showing the Trout's Cone of vision and explains how this changes due to depth, current speeds and water types.

The effects of light on the fishing situation are far too many to list and the variables are endless. Furthermore the color of the background in conjunction with light can alter the perception of the color being viewed. With all of these variables to contend with what is the angler to do in regards to preparing practical imitations to entice the trout?

To my way of thinking if you tie the imitation to match the natural insect you wish to imitate and match the color as close as practical sense allows then I believe the trout will see your imitation in the dispassionate way that it views the natural and will therefore eat your imitation. As the light changes, the color of the imitation doesn't actually change. The Olive imitation it's still Olive, it's just that through the changing light the perception of how we see the color changes.

As for those who claim that they fish riffles and fast moving streams where attention to the detail of color is unnecessary I would say this, I have fished mountain streams, and rivers and streams with heavy runs and quick water and even in these waters there are pockets and pools where the water is smooth. I fully agree that in certain situations size and shape may be enough, however I will point out that careful imitations of the proper color will also be effective and will work as well as other pattern styles. However, on smooth streams with clear water having patterns the reasonably resembles the color of the insect that the trout are feeding will give the angler an advantage.

If the colors of an imitation are way different from those of the naturals the trout may notice and refuse your offering. Remember not all flies float on the surface and much of the trout's diet is beneath the surface of the water where they often have a less distorted view of what they are eating.

Imitating the basic shape of the insect is important and as is matching the proper size however matching the size, shape and color does not mean that you have to be exact in these requirements. Often we take this a step beyond what is necessary.

However, I fully realize and accept that many imitations are tied to satisfy both the trout and the angler and I have no problem with this artistic endeavor as long as we realized it as such and not given to allurements which are without merit.

As much as color, size and shape are important I think that the illusion of life is equally important to the success of any imitation and I try to incorporate this factor into all the patterns where it is practical to do so.

I have spent a lifetime chasing trout, tying flies and studying the various methods and strategies to entice the trout to take my offerings. I have also spent years reading the pages of the past masters of this sport and have come to believe that nymphs, emergers and even some dry flies are enhanced by adding the illusion of life to the imitation.

Therefore, I often employed the use of wet hen hackles, soft game-bird hackles and even after-shaft feathers to achieved the look I desire and on some patterns both wet and dry I used legs made of rubber, silicone and manmade fibers like super floss to achieve the desire results.

Remember the rules of fly fishing and fly tying are that there are no rules. In fly fishing and fly tying rules are created by man to control a series of events which really cannot be controlled.

There is nothing wrong with having an opinion on the importance of size, shape, color or the illusion of life. However, to believe that your ideas are always right and everyone else is wrong will stop you from learning and advancing as a fly fisher.

The best advise that I can offer the fly angler or the fly tier is to always be open minded and willing to learn and try different ideas and methods.

Also remember it isn't what the trout's may see, is it what the brain does with the impulses it receives from the eyes of the trout.

Trout are naturally wary; an instinct that has been honed for thousands of years and at times they are indeed difficult to entice to our offerings. However, it is a mistake to give them powers of thought that they simply do not have. It's unlikely that we will ever totally understanding the actions of the trout. There are questions that we will never be able to satisfactorily answer nor were we meant to. For without the mystery and challenge this sport would soon become boring and I sense that if we were always successful and knew everything we might all give up fly fishing entirely and take up golf.

Enjoy & Good Fishin'


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