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

09/02/09

Freestone Streams - Part 4

The freestone stream’s volume of water and rate of flow is strictly dependant
upon Mother Nature. The amount of water in the stream can vary drastically with
the seasons of the year. Heavy rainfall that usually occurs in the spring months
makes the freestone streams large and turbulent and sometimes flood beyond
their normal banks. Of course the spring runoff always causes the streams to
flow out of their banks and usually become unfishable.

In the late summer and fall months of the year, most freestone streams reach
their lowest levels. Sometimes the flow can become so slow and the dissolved
oxygen levels so low that it become tough for trout to survive. This is especially
true in the lower sections of the streams in the foothills. Just a couple of years
ago, several streams in Yellowstone National Park had to be closed due to
excessive water temperatures. In some streams, like the Firehole, there was a
fish kill in certain areas. Many streams had certain hours that the park officials
allowed you to fish and other hours during the warmer part of the day that you
couldn't fish.

It is difficult to conceive that streams above six to seven thousand feet in
elevation can get that warm but they can. Most of the streams in the park are
exposed directly to the sun with no overhead protection from tree limbs. The day
time air temperatures can reach the nineties. The only thing that keep the water
from getting excessively hot is the cold nights. The air temperature usually gets
down to about forty degrees or less most places in the park during the night.
When the snowpack is low from the previous winter and there is little rain, some
of the streams in Yellowstone can become too warm to fish during the day.

At the headwaters, most freestone mountain streams support native cutthroat or
brook trout, depending on whether it is a Western or an Eastern stream. These
fish are usually small, averaging from four to eight inches because they have
less space to live and less food to eat but they are also usually very aggressive
and lighting fast. Most of the time, trout found in the acidic, headwater streams
feed opportunistically. It is rare that they have enough of any one species of
food to feed on. Selective feeding times are few and far between. The angler
usually does not have to be concerned with specific patterns of flies. Most of the
time, attractor or non-specific type flies that imitate a variety of insects will work.


Continued tomorrow....

Copyright 2009 James Marsh