At the headwaters, most eastern freestone mountain streams support native brook trout. In the west, most headwaters support native cutthroat trout. Some of the western freestone stream headwaters also support wild brook trout, or decedents of brook trout that were at one time stocked. 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 these 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 doesn’t have to be concerned with specific patterns of flies. Often, attractor or non-specific type flies that imitate a variety of insects will work fine. That written, there are also times when the trout do concentrate on a particular insect. Depending on the aquatic insect population and makeup, there are usually some species that can cause selective feeding for short periods of time in the headwater streams.
It doesn’t take much to upset the balance of nature in a freestone stream. Many, many factors have done just that. The logging of timber has been a major problem for many streams. The construction of roads has also affected many of the streams and in many different ways. The construction of lakes has also affected many of the streams by slowing down the flow of water and changing the levels of parts of the freestone sections of the stream. Acid rain is yet another adverse factor that has affected streams in the eastern states. The list goes on and on.
For our purposes here, the main thing to be gained from these adverse affects is that anglers should be aware of what makes a freestone stream produce good populations of trout and what adversely affects them. Two important points to stop and register is water temperature (which also affects the oxygen content), and water levels or stream flows. Knowing these two things about a freestone stream is the first and primarily the most important things to know. Water temperatures can be obtained by a stream thermometer. Water levels can usually be obtained from U.S. G. S. real-time stream data. Thunderstorms that occur in a different watershed can change that very quickly.
The next most important thing would probably be the clarity of the stream’s water. The stream levels and flow rates are good indicators of the water clarity but this information alone is sometimes deceptive. Of course, once you are on the stream, you can see the watercolor conditions for yourself.
The pH of the water is yet another factor that affects the trout and its food but it is one you can do little about. You can change the way you fish to adjust to water temperature and water levels, but you can’t adjust for various pH levels. Of course, just knowing the water temperature and level is not enough. The information is worthless unless you know how it affects the trout and how it affects your fishing.
in the foothills, the more diverse type of water will usually support other many species of mayflies, caddisflies and stoneflies. Mayflies may include several species of crawlers and swimming nymphs. The caddisfly population and diversity will increase and include many species of scrapers, predators, and shedders due to the diverse type of habitat. Stoneflies are still usually present in the fast water sections of the stream. Since the water has poured through rocks, gravel, sand and other types of soil, and since organic material such as leaves may have accumulated in the stream, the water in the lower elevations is less acidic than it is in the headwaters. It
will normally support specie of aquatic insects that rely on organic material that has become more prevalent due to the higher pH. Its increased water temperature is also conductive to supporting other insects.
After the stream reaches the valleys it slows down and congregates in larger pools connected by riffles. Since the water temperature is much warmer than the water at higher elevations, and since the pH has become even more alkaline, plant growth may be present. The stream’s substrate usually consists of more soil and less rocks and burrowing mayflies may exist. The caddisfly population may increase since there is a lot more organic material available for the larvae. Shedders, predators and scraper species may be prevalent. Stoneflies my not exist in the less oxygenated warmer water.
Again, knowing what is written above, won’t be of much value, unless you have a good knowledge of how to adjust your fishing strategies and techniques to adjust for various types of water in the freestone streams.
Copyright James Marsh 2013