A wise man once said, “In order to do something, we must first understand what it is we are doing.” This certainly is true for trout fishing. After all, anyone can walk up to a trout stream, impale an insect on a hook, chuck it into the water, and wait for a fish to bite. But this is obviously not the most productive method for catching trout.
There is an art to angling for trout, regardless of whether you use conventional fishing equipment or fly fishing gear. To become a great, both knowledge and skill are required. You must understand the environment that trout live in, so you also learn to see it from their point of view.
In fact, the most important piece of advice an experienced trout fisherman could pass along to a novice is, “If you want to catch a fish, then you have to learn to think like a fish.” Having an intimate view of a trout’s environment will provide you with invaluable insights into their mentality, which will enable you to catch your share. Location also plays a part, and there are many great areas to fish for trout in Minnesota, Michigan, or across the country in states like Colorado and especially Alaska.
Understanding Trout Environments
How do you understand the environment that trout inhabit? First, from the day a trout is born as an egg to the day it dies, there are aquatic, terrestrial and avian predators who want to make a meal of it. So, if a trout is to survive, it must be paranoid by necessity.
As a result, all trout seem to adopt an attitude of, “If it moves, run – and if it doesn’t move, run anyway.” If a trout sees any movement whatsoever within its cone of vision, its first instinct is to dart into the nearest shelter and stay there the threat has passed.
So, as a fisherman, it is imperative that you learn to become stealthy in your approach to a prospective trout lie. In fact, when fishing for trout, it is helpful to adopt the attitude of a hunter rather than that of the average fisherman. This could mean moving along the bank where you can hide by the trees instead of wading up the center of the stream. You can also hide behind boulders or crouch down close to the surface of the water so that you’re below the trout’s cone of vision.
How a Trout Sees The World
Although understanding how a fish thinks is paramount to catching fish, it is also important to understand how they see their world. Although the following description applies to all fish species, this section will focus specifically on trout.
If you were a trout lying on the bottom of a stream, you would see a huge mirror overhead if you were to look up. That mirror would reflect an exact replica of the streambed and anything else located beneath the surface of the water. You would also see a round hole in this mirror located directly above you. This would provide you with a limited window through which to view the world above the surface of the water.
The cause of this phenomenon is a law of physics called Snell’s Law that states, “Any light waves striking the surface of water at an angle that is greater than 45° will enter the water whereas, any light waves striking the surface of water at an angle that is less than 45° will be reflected.”
But, unless you were holding in perfectly still water, your surface view through this window would be distorted by the current and any ripples it causes. So, if you were holding in whitewater as rainbow trout often do, instead of seeing a clear image of the surface world, you would see a white froth of air bubbles and distortions due to the current.
1. Vertical Vision
Keep in mind that the size of your viewing hole for the surface world depends on the depth at which you are holding. This is because Snell’s Law also dictates that the diameter of the hole is two-and-one-quarter times the depth at which you are holding. So, if you are holding at a depth of two feet, you would have a round window over your head approximately four and a half feet in diameter to see the surface world.
The shape of the hole extends at a 45-degree angle from either side with the apex at the trout’s eye, giving trout 90 degrees of vertical vision under the water’s surface. However, once the edge of this angle reaches the water’s surface, it descends at a 10-degree angle. Consequently, trout have 160 degrees of vertical vision shaped like a cone extending upward from their eyes.
2. An Angler’s Angle
This cone of vision is what you need to consider when approaching a potential trout lie. Remember, you will only have a 10-degree angle from the surface of the water to approach the trout unseen. Keep in mind that since this is an angle, it widens the further the apex is from the water’s surface. It also narrows accordingly the closer the apex is to the water’s surface.
Therefore, the closer to the surface a trout is holding, the smaller his cone of vision will be and the deeper he is holding, the wider his cone of vision will be. Also, the farther away you are from where a trout is holding, the less likely it will see you. And the closer you get, the more likely it is that the fish will see you.
The trout’s vision means fly fisherman of average height wading in water approximately waist-deep will only be able to approach a potential trout lie within about 15 feet without being seen. This is even less if you walk along the bank even with or above the water’s surface.
So, if you need to approach the trout’s lie any closer than 15 feet, you need to crouch closer to the water’s surface. You can also use any available cover such as rocks or boulders to hide your approach.
Keep in mind that trout have 330 degrees of horizontal vision beneath the surface of the water, which leaves a 30-degree blind spot directly behind them. Thus, since trout are anatomically designed to face upstream into the current, approach a potential trout lie from downstream. That way, you can approach them within their blind spot.
3. The Lateral Line: Yes, Trout Can Hear
Trout have rudimentary ears, so they can hear some sound beneath the water’s surface. They also have a far more sensitive organ, the Lateral Line, which extends the length of their body. It consists of a group of highly sensitive nerves that enable them to feel pressure waves in the water.
When you’re wading in the water and approaching a potential trout lie, do so as stealthily and slowly as possible to minimize the pressure waves your body creates moving through the water. Otherwise, the trout will sense you coming and refuse to feed. Approaching a wild trout in its natural environment without them seeing or feeling you is a daunting task. It even takes some experienced anglers practice to perfect.
Anyone who can approach a wild trout, cast their fly or lure precisely within the trout’s cone of vision, and make that fly or lure drift naturally to entice the trout has accomplished a phenomenal feat of planning and stealthy execution. If you can catch a trout, you should be proud, regardless of the size of the trout you catch.
Trout Feeding & Food vs. Energy
Trout are born as eggs and as they mature, they grow through different stages according to size. They classify these stages as alevin, fry, fingerlings, parr and juveniles. When the trout become sexually mature it is an adult.
As they grow, a trout must become adept at discriminating what is edible from what is not edible. Trout learn to discriminate by memorizing the size, shape and color of available insect species in their stream. In addition, they look for signs of movement, such as gills along the abdomen of aquatic insect species as an indicator of life. Trout also spend that time swimming in the current to capture food expending energy.
In addition to the various species of aquatic and terrestrial insects drifting the current, there are also numerous species of small fish inhabiting the stream along with adult trout, depending on geographical location. These include dace, chubs, sculpins, and crayfish, along with trout in the various stages of maturity. And all of them are fair game as far as adult trout are concerned.
To catch trout, look at baitfish species in the following manner: If someone were to offer you your choice between a free McDonald’s cheeseburger and a free 20 oz. steak dinner, which one would you choose? You’d go for the steak dinner, right? And most adult trout feel the same way. Trout will almost always consume the largest meal available if it provides them with more energy than they expend capturing that meal. As a rule, larger flies and lures tend to catch larger trout.
The Three Types of Trout Lies
Trout in streams live in a constantly moving environment unlike other types of fish, so to conserve energy, they look for places that provide them with shelter from the current, as well as from predators. These places are called “trout lies.”
As a fisherman, it is important to understand there are three different types of trout lies. Each one serves a different purpose for the trout. Read on to learn more.
1. Sheltering Lies
If a trout sees any movement through that magical hole in the mirror above them that may represent danger, it automatically triggers an unconscious reaction. So, trout will dart for the nearest cover and stay there until they are certain the danger has passed. This type of trout lie is a “sheltering lie.”
It is a place that provides shelter from predators but does not offer access to food. Sheltering lies are under or between large rocks, deep inside dark caves under overhanging ledges or beneath undercut stream banks. This is similar to other types of fish such as big and small bass.
2. Feeding Lies
There are other places in the stream that provide trout with access to food. However, they don’t offer any protection from predators. For this reason, trout only gather in these locations when there is an overabundance of food drifting in the current. One example is when aquatic insects are hatching.
During that time, trout will gather in a feeding lie. Trout often choose a certain feeding lie because it requires the trout to expend little to no energy to maintain their position in the current. The position in the current also concentrates the stream of hatching insects so the trout can eat more while expending less energy.
Feeding lies often occur in calm pools and glides where the water is crystal clear. This way, trout can suspend above the streambed or in the shallow tail of a pool.
3. Prime Lies
A prime lie is the ultimate location for a trout to hold because it offers shelter from predators and easy access to food. No matter what stream, creek, or river you fish, you will always find the largest fish in the prime lies. This is because prime lies are the best real estate available in a section of current. For that reason, the largest, most aggressive trout will always displace the smaller trout in any prime lie.
One way to identify a prime lie is to look for places that would offer a trout shelter. This could be an eddy behind a large rock, behind a log protruding into the stream or on the streambed. It could also be a ledge with a deep cave facing upstream, so trout can see food drifting toward it safely. The key is to look for a strong current that delivers food directly to that lie.
The eddies on the edges of riffles and runs are also prime lies. This is because the turbulent surface of the water makes it impossible for predators to see the trout when they are holding in shallow water. These eddies also provide easy access to food, making them ideal for trout.
In addition, the small pockets found in “pocket water” are also excellent prime lies, as is water deeper than four feet. Even if it is crystal clear, this deeper water usually causes trout to feel reasonably safe. Therefore, they will often cruise there while rooting for nymphs or plucking periwinkles.
Approaching a Trout Lie
Once you have learned to identify feeding and prime lies within a trout stream, you will need to learn how to approach the lie without spooking the fish. At this point, it’s helpful to learn to adopt the attitude of a hunter rather than that of a fisherman.
Trout grow up paranoid because so many predators like to eat them. Consequently, when spotting an enemy, the trout’s mentality is to get out of there. Although not likely trout can recognize humans, they have thousands of years of genetic memory that tells them what a bear looks like. Since humans look vaguely like bears standing on their hind legs, the sight of one automatically triggers a trout’s flight response.
So, when approaching trout in either feeding lies or prime lies, stop and closely examine the lie you intend to fish and its surrounding area. Then create a plan of approach to account for the type of terrain and water flow you have to wade through to reach a viable casting position.
Take advantage of any cover you can use to conceal your approach. Because trout have 160 degrees of vertical vision, it leaves a mere 10 degrees above the water’s surface to hide. So, whenever you can’t conceal yourself with cover, crouch as low as possible. This way, the trout won’t see you when you move into your chosen casting position.
Once you’re where you want to be, remain as low to the water’s surface as possible. Before your trout fishing trip, practice casting while kneeling and sitting, so you can learn to cast from a low perspective.
How to Read a Trout Stream
Understanding a trout’s environment and where to look for them in a stream is not enough to make you a successful trout fisherman. You also need to understand how to identify the various parts of a trout stream. This is because different species of trout have distinctly different habitat preferences. So, they inhabit different parts of the same stream.
It is important for anyone who loves to trout fish to be able to identify each water type. Success means knowing where the trout are holding in each type, as well as how to present a fly or lure to them. In addition, it is vital that anglers identify barren water versus productive water. That way, you won’t waste your time fishing water where trout are not holding.
1. Barren vs. Productive Water
To find trout faster, you need to be able to identify barren water from productive water. Heres how:
- Barren water is too shallow to offer protection from avian predators.
- Barren water has a bright, sandy bottom that negates trout camouflage. In fact, it makes trout more visible to their predators.
- Productive water is at least 12 feet deep or more.
- Productive water has a dark bottom and is directly in or adjacent to the main current, too.
Avid anglers have names for the different types of water in a trout stream. Under natural circumstances, the laws of stream hydraulics dictate these sections occur in this order: riffles, runs, pools and glides.
2. Fishing Riffles
A riffle is a section of the stream where the current is fairly swift, but the water level is fairly shallow. Also, a riffle flows over a bed of small, round rocks or pebbles. So, the entire surface of a riffle consists of small wavelets and mild whitewater.
Consequently, riffles are the aerators of the trout stream. Because they hold the most dissolved oxygen of any section in the stream and offer easy access to food, the entire riffle becomes a prime lie if it is deep enough. There is a method to fishing a riffle. Just follow these simple steps:
- Station yourself either downstream or adjacent while facing the riffle.
- Then mentally divide the riffle into lanes about a foot wide.
- Next, cast your fly or lure to the top of the first lane closest to you.
- Let it drift for the entire length of the riffle or as far as you can.
- Then, pick it up and recast it at the next lane over and let it drift the length of that lane.
- Repeat this process until you have covered the entire riffle from side to side.
It may sometimes be necessary to wade into the riffle to reach the next lane. When holding in swift current against a flat bottom, all trout need to do is place their lower jaw against the stream bed. The current pushes them down and holds them there just like the wing on the rear end of a race car. To obtain food, trout slightly tilt their pectoral fins and the current causes them to rise or descend through the water column.
3. Fishing Runs
A run is a section of the stream where the current becomes narrow, swift and is usually quite deep. Because the current is much swifter in a run than in a riffle, the prime lies in a run are adjacent to the current, rather than directly in it.
Therefore, to find the prime lies, look for large rocks either above or below the surface of the water. Also look for undercut ledges that create eddies. Eddies provide trout with shelter from the current, while also providing access to aquatic insects drifting in the current.
To fish a run, drift your fly or lure in the current as close to those prime lies as possible. This way, the trout has the least amount of distance to cover to seize your fly or lure. In addition, runs often extend into a pool below them. In this case, you will often see a tongue of swift water extending into a body of calmer water.
When fishing runs in pools, cast your fly or lure to the top of the current tongue along the edge of the seam between the swift water and the calm water. Then, let it drift or retrieve from it the entire length of the current tongue.
4. Fishing Pools
A pool is a small to large section of stream with a flat, calm surface. Pools can be shallow, deep or anywhere in-between. But they all have a relatively calm, smooth surface. This makes it much easier for predators to spot trout in pools. So, trout have evolved super-effective camouflage to prevent predators from detecting them when holding in calm water.
When you take a dark-colored object and place it on a light-colored background, the dark object is obvious because the light background outlines it. And the same thing happens to trout when they swim over a bright, sandy pool bottom.
Therefore, the prime lies in a pool are at the head of the pool where aquatic insects drift with the current to enter the pool. They will also be along the edges of the current tongue that extends into the pool from a run or waterfall above it.
However, if it is a large pool, there are other places where the trout will hold, such as:
- Any area with a dark bottom or a shadow from an overhanging tree, especially if it is strewn with various-sized rocks.
- Behind or beneath logs that extend into the stream from the bank or are submerged and lying on the streambed.
- Along the banks under overhanging trees if there is enough current to deliver a steady flow of aquatic insects.
5. Fishing Glides
A glide is a large pool that is too long to be a pool. In a glide, even though the current is steady, the surface is calm. For instance, picture your average backyard swimming pool. Then, picture that same pool 10 or 12 times longer and you will have a good idea of the difference between a pool and a glide.
Consequently, glides are the most difficult of all trout waters to fish because the surface is calm. Also, the water is deep enough that the trout have a wide cone of vision. Thus, they can easily see any angler coming from a long way off.
Due to the calm current in glides, trout cruise rather than hold in a particular position. Anglers often have to search for trout when fishing a glide. To fish a glide, plan on making long casts that will gently land on the water’s surface. That will help you can stay out of the trout’s cone of vision.
Also, rather than fish the entire glide blind, stay on the bank and use the intervening foliage to hide your presence. Slowly sneak upstream while looking for cruising trout. When you spot a trout, move back downstream beyond its cone of vision before casting your fly or lure.
All novice trout fishermen can become adept at reading a trout stream and differentiating between barren water and productive water. Also, determining where the prime lies are and how to present lures effectively in them will make you a successful trout fisherman.
Successful Trout Fishing
To catch more trout, understand the environment where trout live and feed. It helps to envision things from their point of view. Factors such as living in a viscous, constantly moving environment affects both trout mentality and their actions.
Always keep in mind that the surface world is foreign to trout. Even though they occasionally feed on the surface film, trout prefer to feed subsurface where they can use all their senses. And lastly, keep the food versus energy equation in mind, because it governs all fish species in all types of aquatic environments. This equation dictates their actions, as well.
With this newfound knowledge on trout fishing, you’ll soon be out on the waters achieving an awesome catch.
My articles appear in Marketing Edge Magazine, on Gizmogrind, and with various Medium publications. But one thing hasn’t changed in all of my life: no matter where I was or what I was doing. I’ve always loved to be outdoors.
A man needs nothing more than a good flannel shirt, a well-worn pair of jeans, and comfortable hiking boots. I don’t go for all the fancy luxury stuff. Suits are uncomfortable and shaving sucks.