As with all functioning society, a set of moral rules and conduct is in place to maintain common civility. Fly Fishing is no exception to the imposition of a moral code governing its rules and ethics. Various flavors of this code book have been authored from time to time leaving many confused as to the rights and wrongs of the sport.
I would like to include a long forgotten but most important commandment: Never fish too close or violate the right of way of another fisherman. It is always first come first serve out there. To maintain civility between us all, you should always ask permission before entering another anglers beat, typically delineated by obvious structural changes in the water between riffles and pools. Otherwise you will probably get punched you in the eye or verbally humiliated in front of your wife and kids.
Read about the "Seven Deadly Sins of Fly Fishing" here.
Not every river you fish will feature endless arrays of perfect pockets, pools, seams and structure in which to easily locate fish. Sometimes, we have to find fish in water that has less distinct characteristics. Rather than waste time blindly casting to empty water, possibly putting down fish with our efforts, stop and take time to observe the surface characteristics of the flow.
Laminar flow can be the most enigmatic water to decipher. It is water that flows at an even speed from top to bottom bank to bank. I normally walk by water that exhibits no obvious structure in which to target my effort. Smooth even currents from bank to bank merely bumping over the rubble is akin to fishing on the moon. I know fish are present, often seeing rises out in the nondescript waterscape, but fishing this water requires more time and effort than casting to fish around obvious structure.
If you do chance upon a feeding fish in a section of river that is laminar in structure, spend some time observing where that fish is located. Even without the telltale signs of current seams, the location of drifting insects and fish are not left to chance. There is a structure at work that the fish use to thier advantage.
Fish will use whatever structure is available to them within the limited confines of a river. Sometimes we must look at less than obvious structures in the laminar sections of water. When looking at laminar flow, observe the structure of the river bottom and speed of the current. If the substrate consists of only sand, silt or very small cobble, with a flow that is walking speed or faster, you are better served moving along in search of something else. However, if you find laminar walking speed flow with a substrate that consists of bowling ball sized cobble you are in luck. You have found water that may contain fish. Small boulders create micro vortices that can hold a fish in the current, so the fish spends very little effort in maintaining its position. Deschutes River steelheaders know this when they fish those classic named mile long runs.
Before you wade into the river and start casting with the usual routine of starting in close working your way out in a clockwork shotgun fashion, take time to look at the surface of the water and try and find the “lanes” that do exist. Lanes are the micro seams that slip past each other funneling everything that drifts downstream into narrow bands. The best way to find the lanes is to find the bubbles. Are the bubbles accumulating in a concentrated area? If so you have found your lane. It may take some time to train your eye to look for a higher concentration of bubbles gathering in an inch wide seam amidst an even dispersion of bubbles, but when you do, you have found your area of concentrated effort. Fish will be located within close proximity of these micro seams in order to easily slip away from thier vortex and inspect a likely morsel.
In the images above, I have used the tools of photography to illustrate where micro seams actually occur. In figure 1, we see a general random dispersion of bubbles on the surface in a section of laminar flow over bowling ball sized substrate. In figure 2, I exposed the image longer to blur the lines and now you can see the micro lanes as faint white stripes, so that you will know better where to concentrate your efforts.
Beneath the rippled current of a trout stream, a complex food web plays out far greater than many anglers realize. The basic biology of a trout stream is often hidden well out of our view unless we are willing to explore the depths, which often requires getting wet and cold. At the very bottom of a fluvial food chain is a bio-film - powered by sunlight and dissolved nutrients - that covers the rocks, plants and woody debris upon which benthic macro invertebrates feed. Slightly higher up the taxonomic ladder are the benthic macro invertebrates, underwater organisms which lack backbones. Macro invertebrates such as insects, worms, crustaceans and isopods feed on the bio-film, then become food for other insects, birds, small fish, and ultimately, the trout we love to pursue as a favorite game fish.
Taxonomists have divided the entire known biological world into eight categories from domain, kingdom, all the way down to genus and species. For a fly angler wanting to choose the right fly, it is important to know at least the family orders of the three primary aquatic insects. A familiarity with the three dominant taxonomic families is a must when choosing the right fly, as each family has its own distinct shape and life cycle.
The three families of aquatic insect that we must pay close attention to are: Ephemeroptera, Plecoptera and Trichoptera, otherwise known as the Mayflies, Caddisflies and Stoneflies (EPT). Each of these families of insect has its own unique life history and key role within an aquatic food system. Each EPT family category is not hard to recognize throughout the individual life stage. Mayfly adults have a distinct pair of upright wings with a variety of three tailed larva known as nymphs. Caddis adults have tent shaped wings, with the larva stage having tubular, worm shaped bodies, and often, external shelters they build and carry around with them. Stonefly adults have two pair of wings that fold flat over the back, and the larval form are often large and robust crawling about the rocks.
Keeping a simple collection of fly patterns to imitate these three categories is the very foundation of a quality working fly box. It is easy to get drawn into an endless array of fly patterns filling the bins of a well stocked fly shop, each fly pattern calling out its own special fish-catching allure. However, expert fly anglers know that simply a small collection of fly patterns always gets the job done. The reason only a few patterns are all that is really needed is that they imitate the three families of aquatic insects very well.
I have selected a small handful of fly patterns that serve as a foundation to imitate the EPT families. The fly patterns are based on a general size and shape of each family with enough impressionistic qualities to possibly imitate more than one family by altering its size and color. Each season, I narrow down my collection of patterns based on general effectiveness. New patterns emerge from the vice that simply outperform old patterns from previous seasons. I noticed that if I focus more on impressionistic imitations with a focus on the EPT factor, the better my angling day.
Good science has no need to reinvent the wheel. The wheel is already perfect in its intended purpose: to roll. The same holds true for many fly patterns invented long ago. There is no need to reinvent something that is already perfect for its intended purpose. However, like the wheel, we can alter it to suit our intended use without altering its core functionality. When choosing a small collection of fly patterns that function to imitate the EPT group, I look at the so-called "wheels" of fly design to select the tried and true patterns to serve as the foundation of a fly box. Having selected a core group of fly patterns I can then alter their size and color to imitate even more possibilities. In most cases I have stripped the original fly down to its most common element, to impressionistically imitate the basic shape, size and color.
The following are my favorite patterns for each family, with a focus on patterns that can fall within multiple families. If a fly pattern can fall within multiple categories, it earns top spots in this collection. I am focusing on nymphs alone because the imitation of adults typically requires more exacting imitations rather than impressionistic fly patterns. I also spend 99% of my time searching the water with nymph patterns.
- Pheasant Tail Nymph
- Gold Ribbed Hares Ear Nymph
- Czech Nymph
- Gold Ribbed Hares Ear Nymph
If we break down the shape of each of the EPT group, the single common denominator for all of them is a round, tubular shaped abdomen usually tapered at one end. In fact, beyond the EPT group, other families also have the same simple tubular shape. While many mayflies have different shaped abdomens, differing from torpedo to suction cup discs, if we blur our eyes for a second like artists do while painting, we would lose detail and a general shape of form emerges. In most cases, a simple tapered tube shape is the dominant form most frequently observed in benthic macro invertebrates.
I have snorkeled many salmonid streams performing fish counts and identifications including benthic macro invertebrate sampling. I frequently see a behavioral pattern with fish holding in feeding positions within the stream channel. Fish will move from side to side and slightly upwards a few inches to take in any small object that has a cylindrical shape. Many times that object is just a broken twig or leaf stem that is then quickly ejected as a non edible object. The importance of this observation tells me that fish are prone to sampling anything that has a common cylindrical or torpedo shape common to most aquatic macro invertebrates.
Most of my angling time is spent fishing in a general searching pattern, probing likely fish-holding locations with these attractor style nymph patterns. This is the time I use any of the general attractors that I have mentioned, patterns that have the general size and color of many of the insects commonly found in my river. It is only when fish key in on a specific insect at a specific moment in that insect's life cycle that I will then fish patterns designed to specifically imitate that instance.
There are a few basic visual clues one can learn to observe about streams in order to narrow the window of where fish are likely holding, especially on big rivers where fish could be anywhere; especially if you don't know how to dissect large parcels of water into smaller subsections. One of the most obvious and often overlooked indicators of likely fish locations are the bubble lines or bubble zones. Bubble lines occur where the current gathers together usually as a result of some instream structure funneling the surface bubbles into predictable locations which also funnels food into a small area making feeding easier for fish, thus expending fewer calories in an effort to feed. Instead of having to swim all over the place looking for food, a fish can hold in a preferred spot where the food is funneled directly to them. Current seams can also define the location of a bubble line or at least prove a location that can also funnel food into a narrow band. Though typically a bubble line is caused by underwater structure. Structure that gives fish a safe location in which to hold and feed. Usually, you will find current seams and bubble lines very near each other,
In the images below, I illustrate some of the most obvious instances of water that contains bubble lines, current seams and structure. If you stumble upon a small section of water that contains all three, take a moment to analyze what you are looking at. Chances are there may be a feeding fish.
In figure 1. You can see several prime structures you should look for when searching streams for likely trout holding water. There is an obvious current seam defining the slow and fast water, obvious underwater structure fish can use to hide near and a bubble line funneling food into the best possible holding spot. Can you identify where the fish should be in this picture?
No, this blog post is not about a magical river flowing from the headwaters of the Unicorn Mountains, and if you learn it’s secret language, you could read a story about a magical voyage long ago; rather, it is about knowing where fish can be located within a stream based on observable hydrological and structural characteristics.
As a child learning to fly fish, I was always told that being able to “read the water” is an essential skill for an angler's success. At the very least, understanding the fluid dynamics and structural characteristics of a stream can lend the angler the ability to find fish within a given location.
From the age of ten onward, I dedicated myself to learning about where fish like to dwell within the dynamic world of moving water. I recall sitting in the passenger seat on long drives into the mountains looking at the streams along the road. “Look at that spot; that ought to be a good spot to fish,” I would say, when I identified what looked like a fishy looking fluvial characteristic. Sometimes, I would beg my parents to stop and let me out so that I could at least make a couple of casts in another fishy looking spot just to see what would happen. I always brought my fly rod with me on family road trips into the mountains with an optimistic hope that a lunch spot would afford me at least a few minutes to practice my fly fishing skills.
When I was 42, I left my previous two careers in favor of pursuing my fisheries biology degree. I spent a summer working as a stream surveyor for the United States Forest Service. Because I had so much previous experience being able to locate fish in a stream environment, I was tasked with conducting stream snorkeling surveys, looking for coho and bull trout. I later learned more scientific terms for defining different stream classifications and hydrological features both in school and on the job. I now have a language I can speak for describing fluvial fish habitat.
I was scouting new water today while taking a bank side stroll with my wife. As we walked along I mapped out this rather featureless beat I might add to my guiding options. We pressed on hoping to find some water with more definition that would appeal to my fish finding senses. I saw an angler working some completely nondescript water, water that I wouldn’t even string up a rod to fish (see my post about laminar flows). To me, it would be like fishing on the moon. There would likely be fish present in that location, but there is nothing unique about the structure to give one a visual clue as to fish location. I then realized that the angler I observed might not be skilled at reading the water, or his skill set may not be strong enough to confidently fish the water with more defined structure and dynamic currents, like those located just upstream from him.
I often see anglers fishing in water I rarely stop to explore. I used to wonder if these people knew something that I didn't, or if they just were not educated enough about reading the water? I know, after having snorkeled in plenty of water like the nondescript boulder flats I see anglers frequently fishing, that the fish are few and far between in those locations. Perhaps they are happy with the occasional fish that they work so very hard to catch?
It would take me a hundred pages to describe the preferred trout habitat and the techniques to fish each and every one of them. To ease your pain, I will parse this information for you into smaller chunks you can read in small doses. Over the course of the summer we will define specific hydrological features and how fish utilize them. I will try to include as many videos and illustrations as possible, so that I can steer you out of the barren cobble flats with laminar flow into more exciting water full of fish.
I will use a specific language to describe rivers and streams, not only when I am describing fluvial characteristics but also when I discuss benthic macroinvertebrate distributions within a watershed (yawn). Yes, that will be another day.
- Fluvial: Fluvial is a term used in geography and geology to refer to the processes associated with rivers and streams and the deposits and land forms created by them.
- Benthic: The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers.
- Thalweg: is a line drawn to join the lowest points along the entire length of a stream bed or valley in its downward slope, defining its deepest channel -- often having the deepest, heaviest current.
- Laminar Flow: In fluid dynamics, laminar flow (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption between the layers. Observed as smooth even current from bank to bank.
- Substrate: The composition of the bottom of the stream from sand, silt, clay to stones, cobble and boulders.
- Embeddedness: The degree to which fine sediments surround coarse substrates on the surface of a stream bed is referred to as embeddedness.
- Riffle: A riffle is a shallow section of a stream or river with rapid current and a surface broken by gravel, rubble or boulders. Riffles are instrumental in the formation of meanders, with deeper pools forming alternately.
- Pool: in hydrology, is a stretch of a river or stream in which the water depth is above average and the water velocity is quite below average. A pool must extend from bank to bank. A side pool does not extend from bank to bank but to the side with faster water defining one side if the pool. A side pool will generally have a current seam and back eddy characteristics.
- Current Seam: the parallel junction between two distinct current speeds as they slip past each other.
- Foam Line: Where bubbles gather in specific patterns along the length of current as defined by that current.
- Pocket Water or Pocket Pools: Small bank side pools outside of the Thalweg that are defined by and protected by boulders that cannot be technically defined as a pool.
- Wetted Width: the width of a body of water as described by the current water level.
Up Next: Current seams and bubble lines. What do they mean?
I frequently spend time snorkeling trout streams so that I can observe the aquatic world in action. While snorkeling, I will grab ahold of rocks or boulders, so that I can hold myself in the current and gain a vantage point to observe fish holding in the current. I will watch fish moving around in small holding areas mouthing almost everything in the drift. Most times the object - be it a small twig, leaf stem, seed or any manner of detritus that gets blown into the current- is investigated and most likely ejected. Sometimes, this morsel is a real food form and is taken deeper into the mouth and crushed with pharyngeal teeth before being ingested. I can imagine that twigs and most artificial flies might be too tough to crush, so are immediately ejected out of the mouth with a quick reversed opercule pump motion. In the case of an artificial fly, often the rejection occurs before we can detect the take.
A recent discussion I had on facebook with an angling friend in the Pacific Northwest has me re-examining what I know about habitat conditions, namely water temperatures and metabolic demands placed on the fish throughout the season. He made an observation that fish are not as selective in temperature ranges in the 40º-50ºF range, while above 50ºF the fish become more selective.
The optimal temperature range for trout growth is between 42º-52ºF. Between these temperatures, fish are at their peak and can afford lower degrees of selectivity so they feed more actively and gain weight as rapidly as possible while the temperatures are optimal. Also, it’s important to note the stream order we are observing. Lower stream orders stay cooler while higher stream orders generally run warmer. Higher stream orders also have noticeable changes in food availability. In higher stream orders - lower in the watershed - the diversity of macroinvertebrates changes to include a higher ratio of aquatic larvae such as the water snipe and crane fly. I have sampled large rivers such as the Madison, Colorado, Roaring Fork and routinely pull out large numbers of Athericidae larvae, the water snipe fly. This aquatic larvae is easily imitated with a common olive green rock worm pattern and is often mistaken for a green rock worm.
When times are lean and the guides are casting #22 baetis or #24 trico imitations in the late summer, trout will often move further for a big juicy aquatic larvae as it drifts by (stream order 3 and greater). This is opportunistic feeding at its best, more caloric reward per unit of effort. I regularly defy the conventional wisdom of casting small flys in the late summer when I regularly catch very large trout with one inch long larvae pattern used as an anchor fly while the smaller beatis is often ignored.
One other point I would like to make is that as the season progresses, mayflys, stoneflys and caddis that are available tend to diminish in size yet the aquatic larvae and free living caddis larvae keep growing. By late summer I can be fishing an aquatic larvae or even a free living caddis almost an inch long. I also notice that my daily benthic macro samples start revealing more and more water snipe larvae and less of the big three bugs on which we often focus our attention.
Fly patterns such as Sawyers Killer Bug, the Utah Killer Bug and my Latex larvae are the perfect imitation.