The other night at our local “watering hole”, a group of us were talking about trout fishing when one of the guys said, “what frustrates me is, I don’t know where to look for trout”. “In response, a fella replied, “Just fish near the bridges”, which brought a roar of laughter from the group and a need for another round. But what had been brought up is a great point. One that I will admit, I take for granted. Knowing how to read a trout stream to catch more trout is key. But what does that mean, “read the water”?
How To Read A Trout Stream To Catch More Trout? Understanding the relationship between three elements is the key to being able to read a trout stream.
- Trout habitat
- Water flow
- Trout behavior
“Reading the water” is knowing how to recognize “structure”. Understanding how water travels around, through, under, or over structure (obstacles) and where a trout positions himself to take advantage of the current with regard to the structure.
To understand the relationship between these things we first need to gain a basic understanding of what these things are. What is structure, really? Water flow and its effects on the structure and what does a trout need to survive? We’re going to take a closer look from a fisherman perspective and a trout’s perspective to see how to read a trout stream.
What is a Trout Stream?
There are three types of streams that hold trout. (to find streams in PA click here)
- Freestone streams
- Spring Creek/Limestone streams
Freestone streams collect their water from the runoff of snow packets and rainfall. As they flow, additional feeder streams add to the flow eventually turning small streams into large rivers. As the water of freestone streams flows, it erodes the rocks, rounding them while reducing their size into gravel, rubble and sometimes sandy bottoms, forming the bed of the stream. These streams are subject to high water periods from spring runoff or if rainfall is abnormally abundant. A result of high water, stones are moved by the current which is how the streams earned their name as “freestone streams”.
The water of a freestone stream is usually cold and because of the tumbling over rocks, it’s highly oxygenated. The turbulent currents in freestone streams provide an ideal habitat for trout as well as other aquatic life which is a required food source for trout. A typical environment of a freestone stream consists of hardwood trees lining its banks which provides shade in the warm summer months and a smorgasbord of terrestrial insects for trout survival. As a freestone stream flows farther down and out of the mountains it gets wider and the water temperature warms until it can no longer support trout populations.
Spring Creeks or Lime Stoners
Spring creeks or Lime stoners are streams whose origins begin from underground bodies of water. Penn’s creek here in Pennsylvania is a good example. As opposed to freestone, limestone stream banks are not as eroded and are usually at the level of the stream. Water temperatures of lime stoners are consistent, fluctuating less during the day with average year-round temperatures of 52 degrees F. This even-temperature allows for in-stream plant life to grow and flourish providing an almost unlimited food supply for the abundant invertebrate life, particularly crustaceans, like scuds and crayfish. The chemistry of a lime stoner differs from freestone streams regarding pH which also aides in the productivity of biomass. Lime stoners are the ideal trout stream because of the consistent low water temperature and abundance of food available year-round.
Tail Water is a term used to describe a creek or stream that flows out of a lake or reservoir. These waters are subject to the release of water from the dam regulated by the dam’s operators. Tailwater temperatures can vary as well, depending on whether the water is bottom or top release.
In addition to the above, trout waters also fall into three other noteworthy categories:
- Class A: High-quality trout waters sufficient enough for natural reproduction to sustain populations of wild trout and will require no stocking of hatchery trout.
- Class 2 (B): Streams that may have some natural reproduction, but not enough to utilize available food and space. Therefore, stocking is required to maintain a desirable sport fishery.
- Class 3 (C): Lastly waters that are marginal for trout habitat with no natural reproduction occurring. They require annual stocking of trout to provide trout fishing. Generally, there is no carryover of trout from one year to the next. We’ll talk about these and their importance in a second.
What is Trout Habitat?
The single most important aspect of a trout habitat is water temperature. Trout survive in waters where temperatures range from the low 40s to 70 with the ideal range being in the mid-50s to mid-60s. Forested streams provide shade to cool water, help prevent erosion, and provide shelter and food for trout and other species. Trout require riffles, pools of varying depths, and a stream’s flow of proper velocities to exist. Streams that consist of boulders, downed trees, and gravel bottoms make for the ideal habitat. Gravel bottoms are essential to reproduction and are used to create “redds” or nest where females lay their eggs.
A trout stream also needs a network of channels to allow trout and other aquatic populations to move to different locations of the stream. Trout move to feed and to rest daily, but also move seasonally in response to changing conditions affecting the environment, water flow, temperatures, spawning, and smolting. (A Smolt is a stage of a salmon life cycle that is getting ready to go out to sea.)
What is the Feeding Behavior of Trout?
Feeding behavior is the most obvious thing to know when fishing for trout. Trout prefer to select food providing the greatest benefit in terms of calories and ease of capture. They seem to sense where to get the most food with the least amount of effort. They then reside in areas where food is delivered to them or “drifted” to them. These “drifts” are the head or tail of a pool, channel bends, and where current flows around rocks or objects in the water, for example. Larger trout will concentrate in areas where small fish or crayfish are plentiful.
Where Do Trout Rest?
Trout like to hide among branches of fallen trees, the trunks of these trees, in the shade of overhanging branches, tucked under rocks and deep pools. These areas are where they will “hang out” with little effort on their part to maintain their position. At the same time, staying within easy striking distance of stronger currents where food drifts by. They will lay close to the creek bottom when resting where the current flow is usually the weakest.
Trout instinctively know the difference between faster and slower currents and where these currents meet, often referred to as “edges”. These edges are sometimes difficult for the angler to see or detect. Current that circulates back behind a rock forms an “eddy” or area of slower circling water. Trout like to sit behind these rocks but close to the stronger current coming around the rock. Here they can conserve energy while waiting for an enticing morsel to drift by.
How to Read a Trout Stream’s Structure?
Going back to the three categories I mentioned earlier, it is important knowing the difference between stocked or natural streams. Stocked streams, especially in the early season, are predictable as to where trout are. The joke about the bridges earlier in this piece had a lot of truth to it. Pennsylvania is noted for dumping trout at the bridges or easy access points along the road. Typically if you fish these locations knowing how to read a trout stream will be less important to catch trout. But fishing a trout stream with natural reproduction along with stockers or no stockers is a different story.
Assuming we’re on a good trout stream with natural reproduction, we need to look for obstacles in the water, rock formations, shaded areas, shallow riffles, deep holes, small feeder streams coming into the creek, undercut embankments, sharp bends in the creek, areas where the current is funneled to cause a faster concentration of flow. Ultimately, as you survey these items and areas, the question to be answered is, is this a place that a trout might be? Does it provide shelter, food, and contrasting current flows?
Obstacles are the easiest to identify and to assess. A fallen tree in the creek, especially if it has been there a long time, creates cover and shadows for a trout to lurk. Boulders, rocks, and rocky formations are good places to find trout. Another area to find trout is where small feeder streams come into the main creek, especially in late spring and summer. Feeder streams provide cooler more oxygenated water. A bend in the creek is another not so easily identified place to explore because the current erodes the outer bank of the creek causing undercuts where trout can hide.
Why is Current or Creek Flow The Most Important Aspect?
Once you have located a likely spot based on the structure, try to assess how the current flows into the area. The flow of the creek will be stronger in certain areas as compared to other areas. The main flow isn’t always down the center of the steam either. As in the picture below, the current is strongest against the far bank and under the overhanging tree.
Remember too, trout like to position themselves on the edges of differing current strengths, so you need to figure out where the edges might be. Let’s use the following hypothetical to help us get a better understanding of everything we have talked about regarding how to read a trout stream to catch trout.
Imagine we have walked up a trout stream to discover a pool where the creek comes in from our left and turns sharply to our right. At the top of the pool, is a riffle and just below the riffle is a log partially submerged. The current runs into the bank and turns running under a tree growing out of the bank that leans over a deep pool. Ask yourself the following questions.
- Where exactly does the current flow?
- How does the current flow around the structure present in the stream? Over, under?
- Where does the current enter and exit the pool?
- Where does it appear to be stronger or slower?
Next, if I were a trout, where might I sit with regard to the current and these obstacles? (Remember, ease of access to drift or best ambush position.) How would a trout sit in relationship to the submerged log, the undercut bank? Would he be near the riffle feeding or the tail of the pool feeding? Take your time to study the situation before casting. Try to target what you think is the best starting point for you to cast.
Why is the First Cast the Most Important Cast?
Studying the situation by watching the current for a while, try to imagine where a trout may be holding. Then visualizing how you are going to present your fly to those locations, is “reading the water”. Once you decide where you think a trout may be positioned, you will need to place your offering into the current to “drift” into the trout’s a position. This is what I refer to as “perfect presentation time”. The first cast into a likely spot is your best chance at fooling a trout. (Click here to learn more about casting a fly rod)
Equally important, is to position yourself to make the cast from an undetectable location to the trout. If you spook him your chances have just been greatly reduced for you to catch him. Wild trout, especially, are keenly aware of their surroundings and they waste no time running to cover at the slightest sign of danger.
How to read a trout stream to catch more trout falls into two parts, the first is to know if you are on a stocked or wild trout stream. Once you select a stream based on the above you can fish accordingly. Stocked trout, especially when first stocked are easy to catch and will chase just about anything. Predictably they will be schooled at the points where they were stocked and the ones that survive the initial weeks will eventually spread out and become more acclimated to the stream.
Wild trout though can be anywhere in a stream. Those anglers who understand the structure, water temps, creek flow and how a trout interacts with these things greatly increase their chances of catching trout. In other words, understanding the relationship between trout behavior, trout habitat, and water flow is the key to being able to read a trout stream and reading a trout stream is key to consistently catching trout.
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Do Trout Swim Upstream?
Trout are in the Salmon and Char families. Salmon and rainbow trout return from lakes or even the ocean, and swim upstreams for reproductive purposes. They follow a familiar scent leading them back upstream to the location of their birth. Trout, in general, will swim upstream in search of colder and better-oxygenated water.
What is the Difference Between Char and Trout?
Char is of the trout and salmon family, Salmonidae, and often have smaller scales than their relatives. They are distinguished by light, rather than black spots and a boat-shaped bone (vomer) that are toothed only in front and roof of the mouth.