03/25/10
Insects and other foods the trout may be eating:
1.   Blue-winged Olives
2.   Little Black Winter Stoneflies
3.   Quill Gordon Mayflies
4.   Blue Quill Mayflies
5.   Little Brown Stoneflies
6.   Little Black Caddis (American Grannoms)
7.   Sculpin, baitfish and small crayfish (Imitate with streamers)
8.   Midges

Fly Fishing Tailwaters - Part 4
The aquatic insects, crustaceans and other trout food that exist in tailwaters varies
a huge amount from one stream to another. One big factor is the aquatic insects
and other food that existed in the stream prior to the construction of the lake that
formed the tailwater. Biologist have speculated that some aquatic insects get into a
stream by anglers, birds, animals, etc., moving the eggs of other insects to the
tailwater streams from other nearby trout streams. The extent and amount of such is
unknown. Most of the aquatic insects in a tailwater were there to begin with. In the
South, there are very few streams that were cold water trout streams prior to the
construction of the dam that formed the tailwater. Most were warm water streams.
The species of aquatic insects in a warm water stream differs from that of a cold
water stream and consequently, the aquatic insects that end up in the cold tailwater
consist of only a few species that would normally exist in a trout stream. When the
warm water stream is changed to a cold water stream, not all of the same aquatic
insects will live and thrive in the cold water.

For example, when the Frying Pan River in Colorado was damed, it was already a
cold water trout stream. It already had many different species of aquatic insects and
consequently, the tailwater continued to have all of those that existed in the
freestone part. However, that isn't all there is to it. The tailwater has more in terms
of total quantities and numbers of species present.

When a lake is formed, it stratifies into layers. I wrote about this a few days ago. For
example, an existing cold water stream may have had only a few caddisflies of a
certain species that only existed in the marginally warm areas of the existing stream.
However, If another dam was constructed in the stream above the lake, its tailwater
may end up with a huge caddisfly population of those species that prefer slightly
warmer water. This often happens with midges. There also may be many species of
caddisflies in the lower end of a tailwater, or near the point the water temperature
begins to increase back near the marginal limit trout can exist. These streams often
end up with huge caddisfly populations. Such is the case on the Holston River
tailwater. Its headwaters is another tailwater. But for comparison, the South Holston
tailwater receives water from the South Holston River that is cold enough in its
headwaters to hold a few wild trout. Its headwaters have a huge population of
mayflies and well as caddisflies, midges and stoneflies. That is why its tailwater has
a huge population of certain species of mayflies, like the Sulphurs.

Most of the southern tailwaters have only small populations of certain species of
mayflies, if any. There are usually some caddisflies that can live in marginal
cold/warm water and lots of midges. They also have a good population of insects
normally found in the marginal areas of warm/cold water. That's why black flies and
other two-winged flies exist in many southern tailwaters.

What all of this amounts to, is that each tailwater has to be taken separately on its
own merit because no two are alike. The available trout food may vary considerably
from other nearby tailwaters. That is why you will find the fishing strategies, methods
and techniques varying from one to the other. For this reason, I will go over some of
the tailwaters within a half days drive of the Great Smoky Mountain National Park
during the next few days.

Tomorrow, I will get into a couple of more insects that are going to start showing up
in the Smokies - the Little Short-horned Sedges and the Hendrickson and Red
Quills. I have previously covered all of the insects hatching now in previous articles.

By the way, the Quill Gordons, Blue Quills, Little Black Caddis and Little Brown
Stoneflies (some almost black) are hatching profusely right now. For the next few
days you can expect these hatches to remain consistent and slowly move upstream.
The water is continuing to warm, thanks to a new wave of nice warm weather. The
trout are very active and are very easy to catch.