Hatches Made Easy:

Light Cahills (Stenacron interpunctatum ) - Duns and Spinners


The "bad" is the Light Cahill duns don't spend much time on the surface of the
water. Their wings dry fast and they depart the water within seconds from the
time they hatch.
The "good" is, they hatch when the trout's metabolism is near its peak and the
trout don't waste any time eating them. In other words, the trout usually take the
Light Cahill imitations readily.

You should present your dry fly imitation in the current seams that concentrate
the surface flow below the areas the slow moving water meets the fast water.
Short upstream or slightly up and across cast work well for this. Keep your rod
high and most of you fly line off the water to prevent drag.
The idea is to make
short cast and cover a lot of water fast as you move upstream. Hit the
most likely spots and keep moving. You will rarely find a heavy
concentration of these mayflies.

The spinners normally deposit their eggs and fall spent on the water very late in
the day or early evening. This happens in the same water that they hatch from. If
you notice them dipping to the water late in the afternoon, I suggest you try an
imitation of the spinner. The same dry fly pattern you used for the dun will
probably work in the faster water. You can try a spent imitation but for the most
part, the spinner imitations would only be effective in the evenings well after the
time you can fish. In fact, in many cases the spinner fall may not occur during
the time you can fish.

Present the upright wing spinner imitation in the same water you would fish the
dun imitation - slower water immediately adjacent too the fast water. Use the
same short upstream or up and across presentation you use for the dun.
If you try the spent imitation, you should place your fly at the ends of the current
seams downstream of the fast water. Place your fly in the same area of the
bubbles that are almost always present near the end of these seams. This may
require a downstream or a down and across presentation.  

You should get the best results from fishing imitations of the dun. This hatch is
as good as it gets for fishing the dry fly.
Trout will take emerger imitations
very well too, but why fish a wet fly when the dry fly works just as well.

This Light Cahill dun is changing from a dun to a spinner. We captured this
image early in the morning. Most likely the dun emerged the night before.

Coming Up Next:
Light Cahill (Stenonema interpunctatum) - Fly Pattern Colors

Copyright 2008 James Marsh