9/12/09
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 50
I am having a little trouble remembering the learning process from back ten years
ago but not what I learned yesterday. I learned that when I am tired, I shouldn't be
posting anything to the web.

The first thing I did was to completely and forever wipe out what I had posted the
day before. That isn't easy to do, even if I made an effort to do it.  The article is
saved in two different places, but never-the-less, I managed to erase it from both
places. The article, mostly about the Madison River, was sent to heaven or hell,
depending on how you look at it. Maybe the locals are getting me back for correctly
calling the Madison River a tailwater.

Even though I had written these articles weeks ago, I noticed the one I posted
yesterday, had a math error in it. Two times four plus is eight plus, not about four
and a half. Specifically, I was referring to a trout in water 4 feet deep and their
window of vision, which is a little over twice the deep in diameter.  The trout would
be looking through a window about nine feet in diameter, not four and a half feet
that I gave in the example. Sorry about that.

Since I have corrected that error, and since I have reviewed what I posted the last
few days, I may as well go ahead and add some current thoughts about it, just so I
don't have to change the subject and write about something else.

With regards to the way a trout sees a fly on the surface of the water within its
window of vision (assuming the water within the window is smooth and not
disturbed), I have been able to get a good feel of it from playing around in a
swimming pool. The window of vision doesn't just apply to fish. It also applies to
what a human would see if they were under the water looking at the surface. They
are restricted by the same physics of light as the fish. What I haven't been able to
quite reconcile in my mind is how a fly outside the window looks like to the trout,
even though I have had Angie cast flies at me in the pool. The reason is that I
realize at a distance, I can see much better than a trout. I am afraid to draw too
much similarity to what I see in the pool at a distance with what a trout would see.

When a fly is outside the window of vision, a trout (or a human) can only see the
portion of the fly that is below the surface skim. As I pointed out yesterday, that may
be the point, barb and lower part of the hook; the legs of the fly (hackle in some
cases); and possible more, depending on just how high the fly is floating in the
water. It could include part of the body of the fly. The trout (or human) would not be
able to see the part of the fly above the water at all. Even if the fly is within the circle
of vision, the trout (or human) cannot see the part of the fly above the water if the
water is rippled, or not smooth. It (or the human) would see only see the part of the
fly below the surface skim.

I suppose everyone has noticed the effects of adding floatant to your fly. The better
floatants keep the fly riding higher in the water with more of the fly out of the water. I
suppose everyone has also noticed that at least at times, it seems to make a
difference in the way the trout take the fly. I know Angie dresses her dry fly with a
paste and a powder floatant after each fish she catches and every few cast when
she doesn't catch a fish. I don't apply floatant until I notice the fly not floating right.

Now the point I am getting to, again, is that when the fly is outside the trout's window
of vision, the trout will first see only the parts of the fly below the surface skim and
nothing above the surface skim. If the fly has a lot of floatant applied to it and is
very dry, then the trout would see much less of the fly than it would if the fly was
soaked and had no floatant. If it completely sunk below the surface, the trout (or
human) would see the entire fly. Since a real natural bug, say a mayfly, is very light,
certainly much lighter than the fly with a hook in it, it makes sense that the trout
would see less of the real fly than it would the fake fly. I don't think you could
possible tie a fly on a hook that was actually lighter than a real mayfly. So it makes
good sense to think the real mayflies have less of their body parts protruding below
the surface of the water than the fake fly.  Now this is only considering the weight of
the fly at the time that a real mayfly is about to depart the water. A better way of
saying it may be that this is only considering the time when the mayfly has dried its
wings to the point it can fly. Prior to that, when it is emerging, much more of the real
fly is protruding below the surface. It seems to me that would be the time the real fly
resembled the fake fly the most.

That said,  I wonder exactly how the floatant, such as Frog's Fanny, affects the fly.
Could it cause the fly to float high enough out of the water that it actually helps the
fake fly become close in appearance to a real mayfly? The more I play with flies,
placing them in pans of water with different types and amounts of fly floatant on
them, the more I think the floatant not only allows the angler to see the fly better, it
also makes the fly appear more realistic to the trout. This is also true when the fly is
within the window of vision in smooth water and the trout can view all of the fly.

Everything I have said about the floatant and height of the fly, is pure speculation. I
have no real scientific evidence to back it up. I do know a real mayfly is lighter than
a fly tied to imitate it with a hook in it. I do know the fake fly would not float as high
out of the water as a real one, and I do know the trout would see more of the fake
fly than it would a real fly that was within a second or two of departing the water.
Knowing that is enough to make me think the fly floatant actually helps the fake fly
imitate the natural better. What do you think?

Copyright 2009 James Marsh