.......................  ......Fly Fishing Yellowstone National Park


Fishing Cold Water - Part Ten

When the water temperature of a trout stream is around fifty degree Fahrenheit,
trout fishing can be excellent. As a matter of fact, it can be as good as it gets.
That's because the water temperature itself isn't a direct factor. It's an indirect
factor that affects the trout's feeding habitats and the extent they feed. Catching
trout doesn't depend on how much the trout eat.  What matters is that you get
your fly in front of them when and where they are eating. You only need for the
trout to eat one thing - your fly. They don't need to eat fifty flies for you to catch
one, or at least I hope they don't. You would be the World's worst fly fisher if
they did.

In general, the ideal water temperature is usually considered to be about
fifty-five degrees. That depends on a lot of things, however. It depends on the
species of trout, for one thing. The cutthroat trout found in Yellowstone are
capable of surviving colder water than the brown trout which are the off spring of
trout brought into this country years ago and at one time, stocked in the park. In
general, the rainbow trout prefers slightly colder water than the brown trout. It
also depends on the amount of food available to the trout and the effort or
trouble they have to encounter to eat it.

If you will pardon the exceptions, and what I mentioned so far is only a few of
many, then I would like to try to cover the basics of how to fish cold water. For
purposes of this article, lets consider cold water to be anything less than fifty
degrees F.

One thing that's always important is the amount of food. We all know that when
most aquatic insects begin to hatch, the trout can eat them much easier than
they normally can find and eat the larvae or pupae. They become exposed to
the trout. They put themselves in a position of being on the trout's dinning table.
They must accent to the surface, or crawl to the banks or rocks to fly away.

Now you're probably wondering what this has to do with cold water. Well, for one
thing, there are a lot of species of aquatic insects that thrive and hatch in cold
water, again meaning fifty degrees or lower. Most of the insects that are called
blue-winged olives hatch in water around fifty degrees and less. Several species
of them, including many species of
baetis, commonly hatch in water that's in the
mid forties. Some species of stoneflies hatch in cold water. They include the
Winter stoneflies and some of the Little Brown  stoneflies. Many of the
caddisflies will hatch in water fifty degrees and below. Species of the second
most plentiful and most important family of caddisflies, the Branchycentridae
family, hatch in water ranging from forty-six to forty-eight degrees. These Little
Black Caddis can cause a feeding frenzy in cold water. Some species of the
short-horned caddis or the
Glossosoma genera, hatch in water from forty-five to
fifty degrees. I haven't mentioned a big one yet, or better put the little ones -
midges. Trout feed on midges all Winter long. They hatch throughout the Winter.
In fact, it's common practice for those that know how to catch trout feeding on
the surface in water that's in the high forties and low fifties.

I think you can see that water between forty-five and fifty degrees can and does
coincide with some big hatches. During those times, cold water temperatures
don't seem to intimidate anglers like it does when it's not the right time for those
insects to hatch. This time of the year, those that don't know any better, often
look at water in that same temperature range as being too cold to fish. That can
be a huge mistake and points to a big misunderstanding of trout.

Just because the big hatches haven't yet occurred doesn't mean the trout don't
eat in water that's in that same temperature range. They eat enough that
catching them isn't a problem provided you know how. In fact, catching a lot of
them in cold water is in many ways easier than it is when the water is in the high

I haven't mentioned water less than forty-five degrees yet, but it's also not that
difficult to have a great day of fishing when the water is within that temperature
range. What do the trout eat in the water that cold when there's nothing
hatching? They eat the larvae and pupae of the aquatic insects. After all,
between now and about the first of May, you will find more larvae and pupae in
the water than there will be at anytime of the year. Most of the hatches ended
months ago and the water is full of aquatic insects. There are several times the
number of developed larvae and pupae in the water now as there will be at the
middle of September, for example.

Copyright 2012 James Marsh