|....................... ......Fly Fishing Yellowstone National Park
Choosing the Right Fly - Part 2
Trout have the ability to hold in slow to moderate current without swimming or
expending a great amount of energy. They manage to do this a lot like birds do
when they are gliding in the wind without moving their wings.
When they are feeding, trout find the areas where the current concentrates the
insects. We call these places drift lines. Trout will position themselves
somewhere along these drift lines. There they will hold their position and stay
focused on what is referred to as their “window of vision”.
They must seek an area of the stream to hold in where the current is not strong.
If they didn’t they would expend more energy than they could take in. Most
often, they accomplish this by seeking a depth where the current is slowed down
by obstructions upstream, usually rocks and boulders. Sometimes they are able
to position themselves on the slow side of the drift line.
The current in the drift line above or to the immediate side of the trout may be
moving along rather fast but the trout is usually positioned in slow to moderately
moving water where they can view objects that come into their window of vision.
If that food is in the form of nymphs, larvae or pupae drifting underwater, then
the distance at which the trout can view it depends on several factors. The
underwater background, amount of available light, clarity and speed of the water
are just a few of them. Normally, in very clear water with good light, they are able
to detect the movement of objects that are within several feet of them. Objects
on the surface are viewed entirely different.
I'll get into that tomorrow
Copyright 2009 James Marsh