06/01/11
Insects and other foods the trout may be eating:
1.    Blue-winged Olives
2  .  Green Sedges (Caddis)
3.    Cinnamon Caddis (mostly Abrams Creek)
4.    Little Sister Caddis (mostly Abrams Creek)
5.    LIght Cahills
6.    Little Short-horned Sedges
7.    American March Browns
8.    Eastern Pale Evening Duns
9.    Sulphurs
10.  Little Yellow Stoneflies
11.  Giant Black Stoneflies
12.  Golden Stoneflies
13.  Slate Drakes
14.  Streamers (Sculpin, Minnows)
15.  Inch Worms

Fishing Low, Slower Moving Water - Part One - Staying
Hidden From The Fish
It's really impossible for anyone to understand much about what a fish can and
cannot see outside the water without first understanding how light waves pass
through water as compared to how they pass through air. In order to explain this,
you first have to have a basic understanding of the physics of light. I don't have the
slightest idea as to how many of you understand this and how many of you don't
but I do know one thing for certain. If I begin this article by trying to explain Snell's
Circle or what many call the fish's "window of vision", many of you will click your
mouse and choose something else to read. It's easy to understand why. Fly fishing
is supposed to be fun and studying the physics of light refraction isn't what most of
you consider to be fun.

Since that's the situation I face,
I've decided to just state the facts and hope
you will accept them
. If not, then I suggest you learn something about light
refraction as it relates to water and air.

Before we get started, let me point out that generally, low water means slow moving
water. This isn't necessarily the case at all points along a small stream. For
example, if the stream drops vertically for a few feet (a waterfall or plunge), the
water is going to flow fast even when the water level of the stream is low. However,
that's an exception. The less water there is in a stream, the slower it is going to
flow. Slow flowing water not only makes it much easier for the trout to see your fly in
greater detail, it also makes it much easier for them to see everything else involved
- your tippet, leader, fly line, fly rod and of course, you.

Trout are more afraid of things outside the water than they are things in the water.
This is because they can see objects under the water much better than they can
see objects outside the water. They can only see objects above the water through
what's in essence a circular window, the size of which changes with the depth of the
fish. Outside that window, they only see a reflection or mirror image of the
underwater world. By the way, if you get in the water and look up through the
surface of the water through your goggles, you will get about the same view as a
fish.

The shallower the fish is, the less it can see outside the water.
I will repeat this in
a different way because it's very important.
The deeper the fish, the more the
fish can see outside the water. It's window of vision gets larger with the depth of the
fish. This means you can approach fish that are shallow without spooking them
easier than you can approach fish that are holding deep. By the way, the diameter
of this circular window is 2.26 times the depth of the fish.

Of course, this assumes the water is clear enough to see through. Just how well the
fish can see through the window also depends on the smoothness of the water at
the surface. When it isn't smooth, or flat like it is in the still water of a pool or lake,
for example, what the fish can see through its "window of vision" is distorted. This
means it is easier to approach trout that are in water with a broken surface, or a
rippled surface, easier than it is trout that are in water that is flowing smoothly or
that has a flat surface.

Let me go back and mention another important point I failed to point out. When fish
see objects through their window of vision, unless the object is directly overhead,
the trout gets a distorted view of the object. The closer the object outside the water
is to the outside edge of the window of vision, the more it's distorted. Object near
the edge of the window are seen by the fish as if they were flattened out. They are
much wider and shorter in height. A six foot tall, slim man would appear to the trout
as a two foot short, fat man with a ninety inch waist..

In other words, the images they see through the window are usually distorted and
not clear. It depends on where they appear in the circular window of vision. This
lack of clarity makes the trout even more cautious. What they do notice for certain
is sudden movements of objects. A tree doesn't scare them but a fly rod's
movement during a cast, or a fly line drifting over their window of vision will spook
them.  

This means the smoother your movements and the slower you approach trout, the
less your chances of spooking them.

There's another point that's very important that has to do with the refraction of light
or what the fish can and cannot see outside this circular window of vision. If an
object is very low to the horizon or below an area that's less than ten degrees
above the horizon, the fish cannot see it at all. Objects that are as low as twenty
degrees above the horizon are seen in such distortion and so blurred to the point
that they are usually not noticeable to the trout. In other words, the higher the
object is above the horizon, the easier it is for the trout to see them.

The further away you are from the trout and the lower to the horizon (the surface of
the water) you are to the trout, the less visible you are. Put another way, if your
going to get close to a trout without spooking it, you better stay as low to the
horizon as possible. If you are standing on top of a boulder high above the water,
forget getting close to a trout that's as far as twenty or thirty feet from you. If you
are crawling on your belly, and the bank is just a few inches above the water level
(horizon above the water) you can probably get within two or three feet of a trout,
even if it's in fairly deep, clear water.

One more quick tip before continuing with this tomorrow. If your approaching a trout
and staying low, on your knees for example, don't make an overhead cast to it.
Your low approach will most likely be in vain. Make a side armed cast keeping the
rod as low to the ground as possible.

Continued

2011 James Marsh