Insects and other foods the trout may be eating:
1.   Blue-winged Olives - mostly Little BWO - Isolated hatches
2.   Mahogany Duns
3.   Midges - hatching in isolated locations
4.   Little Yellow Stoneflies - hatching
5.   Slate Drakes - hatching
6.   Cream Cahills - hatching in Isolated locations
7.   Little Yellow Quills
8.   Needle Stoneflies
9.   Beetles
10. Grasshoppers
11. Ants
12. Inch Worms
13. Crane Flies
14. Helligramite
15. Streamers - matching sculpin, baitfish and small crawfish

The Learning Process - Part 47
The downstream presentation or cast was completely new to me. After a while I
found that I could make them slightly down and across and this would sometimes
help get a drag free drift. Later, I figured out that when I was making a downstream
cast, that I could cast to line higher than normal and bring the tip of my rod down to
the water, it would land the leader in a coil or snake like pattern. Of course this
didn't always turn out right at first. At times I would end up with my leader on top of
the fly line. At times my cast would end up far short of where I intended the fly to
land. I didn't know it at the time but I later found out this is called a pile cast.

The advantage of making a downstream cast or presentation to a trout is that the
trout sees your fly before it sees anything else, including the tippet, leader or fly
line. When you cast upstream or up and across, your tippet and possibly part of
your leader, passes over the trout's window of vision before the fly does. The
downstream presentation is a big help in catching trout when the water is very clear,
the surface is smooth and the current is moving at a slow speed. This means most
spring creeks, some tailwaters and even some sections of freestone streams that
flow over a smooth bottom.  

Now I sure many of you are wondering exactly what a "window of vision" is. The
name itself almost defines it, but not to the point that it provides all the information
one needs. Some anglers go all their life fishing for trout and really never have a
clue exactly what the trout they are fishing for can and cannot see. They all think
they do, but in reality, they are guessing based on what they think they could see if
they were the fish. Any angler will be probably be quick to tell you what the trout
sees and doesn't see, but it is all based on comparing it to their own eyesight and
from an above the water perspective. Few of them have ever ventured under water
and examined things drifting downstream in a trout stream. None of them have eyes
on the sides of their heads with the same narrow, binocular vision.

On many occasions we would set up a camera on a trout feeding in a stream and
video flies coming over or by them, depending on the situation. The idea was to
capture the fish taking the fly. This was not an easy task but we were able to do it a
few times. What amazed me was that when my dry fly would pass right by some
trout, they just ignored it. They looked as if they didn't see it. When I started
thinking about the  trout's window of vision, it occurred to me the trout actually didn't
see the fly.

If a trout is feeding on the surface and staying less than a foot deep until whatever
it is eating passes over its head, the trout isn't going to see anything above the
surface skim that drifts by unless it is inside it's window of vision. The diameter of
this circular area or window is about twice the depth of the fish, or anything else with
eyes that is underwater, for that matter. If a trout is only a foot deep, that means it
isn't going to see something passing by on the surface that is beyond a foot to the
either side of it. If the trout is six inches deep, it can only see objects on the surface
that drift by within six inches of it on either side, front or back. If you are not familiar
with the details of "Snell's window of vision", read
this article I wrote sometimes ago
about the way a trout sees a fly to keep me from having to repeat explaining Snell's
window of vision.

Now there are two reasons I am bringing this up. One is this allows you to make
some cast that drifts by very close to the trout without it noticing your fly. That can
be important because it give you the opportunity to make another cast. The other
reason has to do with how well the trout sees the fly and I will get into that later. Now
keep in mind, the trout can see whatever protrudes beneath the surface of the
water. It just cannot see what is above the surface if it is not in its window of vision. If
you make your first downstream presentation to the inside of the fish, or on the
same side of the trout your are on, then you can work you way closer with each
consecutive cast until you get the fly inside the trout's window of vision. On a
downstream presentation, if you cast  to the opposite side of the fish, and allow the
fly to drift by the trout, the tippet (leader or line) is going to pass over the fish. Once
you practice the drift a time or two and get used to the way the current is taking the
fly, you should be able to get the fly to drift directly over the trout.

When an object passes through the trout's window of vision, it is able to see your fly
at least as good and probably much better than you could from the same position.
They have excellent close up vision. They can focus on objects that are less than
an inch from their eyes. That is why fine tippet works better. The finer it is, the least
likely it will bother the trout. Notice that I am not going so far as to say the trout
cannot see fine tippet because I think they probably can. However, experience will
teach you that the lighter and finer the tippet, the most strikes you will get.

The next time I noticed a lot of anglers fishing downstream was at the Harrimon
State Park at the Henry's Fork of the Snake River that same year. You could see at
least twenty anglers fishing from any one point along the wide, smooth flowing river.
Not one of them was casting in an upstream direction. Most were standing still
casting to one rising trout. Those that hadn't found a riser were moving slowly
downstream looking for one.

If you are fishing this part of the Henry's Fork, you better be fishing downstream or
you will end up wasting a lot of time. The stream has large rainbow trout that are
positioned in ultra clear water with a smooth flowing surface, all of which have seen
their share of flies. It's surface appearance is very deceptive. It appears smooth at
a distance, but up close you will see that the aquatic vegetation on the bottom
creates a lot of conflicting currents. The water is swirling in different directions. It is
difficult to get a drag free drift. When you do, it usually last for only a short distance.

This was just a step in our learning process. I didn't bring it up for you to use as a
method of fishing in the Smokies although we found out it certainly has its
applications in the Smokies. The only time I use a downstream presentation in the
Smokies is one, when I see a fish downstream and want to make a quick cast to it;
two, when I am fishing a soft hackle fly; three, when I am fishing an imitation of a
caddis pupa; or four, when I am fishing a pool with a smooth surface. In other
words, I make few downstream cast in the park, but there are a few applications for
making them.   More in our learning process tomorrow..............

Copyright 2009 James Marsh