Anatomy Of A Small Stream

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When English anatomist Henry Gray published his masterpiece back in 1858, and then died shortly after of smallpox, little would he have realized that it would be well into its 40th edition by now and that Gray’s Anatomy (the textbook, not the TV series) would be a necessary component on the bookshelf of almost every medical student around the world.

In his book, Gray matter-of-factly deconstructs the human figure into its constituent parts. Starting with cells and building the body up again through bones, joints, muscles, circulatory, respiratory and nervous systems, to the outer packaging called surface anatomy. He writes under the premise that you can’t begin to address suffering and disease until you understand the fundamental reason for it, and which particular component of the human condition that’s out of whack.

Of course no two human bodies are alike. A similar comparison can be made to fishing scenarios, where no two water bodies are identical, with the exception, of course, that they all must contain the one essential ingredient to a fish’s survival and an angler’s pleasure – water.

No two anglers are alike, also, which is another compelling reason our sport appears unstructured and random a lot of the time, even though the desired result is always to convince an animal with a brain the size of pea to eat something that it was already hotwired to consume anyway.

A lot of the time, that’s easier said than done.

There are about as many fish-holding habitats as there are fish species that swim in them, from massive sheets of flat water, broad and intimidating rivers, pounding surf beaches or ocean rips that require downriggers with electric winches to probe the fish zone. They are all places where fishermen and women have invented techniques and tackle to angle successfully.

But the quintessential platform for many anglers is the intimate and confining arena best described as the small stream. Like the lurid illustrations of skeleton, muscles and organs and the systems that power them, detailed in Gray’s big book, a modest stretch of moving water makes an ideal laboratory to bone up on the pleasant pastime we call angling.


Skeleton of a small stream

It’s mid-June, shortly after opening day, and I’m on a diminutive Arctic grayling river in Alberta’s Swan Hills.

I’ve walked a long distance from the highway bridge, but my fly has yet to leave my rod’s hook retainer. Where the river gathers pace, I cross the bubbly, peat-stained current and finally find what I’m looking for.

The current in this particular river pushes up against the far bank and gains depth. The turmoil of the little rapids creates bubbles and there’s a foam line snaking down the flow, a metre or so from the undercut. And when an egg-depositing golden stonefly flutters down the froth, its progress is interrupted by a purposeful rise and a swirl appears where the large insect once was.

I swap flies to a Yellow Stimulator dry fly, launch the imitation along more or less the same path the stonefly took and about the same place where the insect disappeared, my fake bug is also assaulted.

When the battle is won, a pink-tinged male grayling, about 14 inches long, with a Jackson Pollock dorsal fin of blue and lemon spots, lies gasping in my net. This was the first of many that memorable summer afternoon, but only after I comprehended the structure of the stream.

It’s been said that 90 per cent of the fish inhabit 10 per cent of the water, which is why I bypassed a long stretch of flat, thin water on my Swan Hills trip before ever making a cast, until I arrived at the undercut pool with the foam line running through it. It was here that I found a combination of structure that made it a favourable habitat for fish.

The overhanging bank provided protection; the deeper water gave the grayling a nearby resting area when they weren’t up in the water feeding. And the seam created by the foam line concentrated the insects that the grayling relied on for food.

Skeletal structure in all its forms is not only present on most small streams, but can also usually be found over a relatively short distance of streambed. So in a few dozen metres you can go from a choppy riffle, to a deep and mysterious corner pool, to an undercut enhanced with sweeping willow bushes, to even little micro-habitats behind boulders, known as pocket water. They all have the capacity to hold trout and grayling because they all have the required elements of skeletal structure.


A small stream’s muscles and organs

I’m on a rushing cutthroat trout creek on the Purcell Range side of BC’s East Kootenay trench. It’s August so most of the mountain runoff has passed, but the river still runs wild and manic.

On the far bank of this chaotic sluice, a sizeable chunk of granite blocks the progress of the flow, creating a long, flat slick behind it for several metres.

Even with a large upstream bend and a lot of arm stretching, I can maintain a drag-free float over the target for maybe three seconds before the muscle of the current sweeps away my floating fly line and the Cutthroat Candy dry fly attached to the end of it.

But the cutties also know this is not their first rodeo. To survive in this hell-or-high-water environment, the fish quickly learn that a long, introspective examination of a food source isn’t practical. It’s use it or lose it.

It took a lot of arm action, but I was able to hook and release half a dozen vividly-spotted west slope cutthroats from that slick before moving on.

The fundamental difference between a stream and a stillwater comes down to a matter of movement. A stream is a dynamic environment. It is forever active and everything that happens within it is ruled and influenced by this constantly changing organism. The fish, the bugs and even the efforts of the angler are perpetually being pulled downstream. Adapting to a river’s muscle is what makes stream angling so cosmic.

Every little playing field that a small stream presents requires a different set of tactics to get the fake food over the fish, which are also waging their own war against gravity.

Working your way up a creek or small river in the foothills or the northern boreal exposes you, the angler, to an almost-limitless selection of moving water scenarios, each to be analysed and a plan executed. Some will require a certain specialized cast, others stealth, while more need a specific fly to perform a specific job. And the most pleasing part of the whole process is that if you happen to blow a cast or stick a fish without getting a solid hook set, there’s another clean sheet waiting just a few short paces upstream where you can begin the whole thought process again.


Small stream systems

Spring creeks, because they are fed by large aquifers and have few, if any, external water sources, are considered by some as the royalty of the small stream world. With their constant flows, stable water temperatures and massive amounts of protective structure, these spring creeks have prolific insect hatches and consequently have the carrying capacity for large numbers of trout. Central Alberta’s North Raven River is considered one of the best. But that doesn’t make the little brown and brook trout creek south of Rocky Mountain House easy. Combined with a flood plain choked with willows, hidden beaver runs and banks of boot-sucking silt, it can easily become an epic nightmare for the faint of heart.

Still, when it’s on, it can be magic.

It’s early June, in the middle of the fly fisher’s Christmas, when a number of big bug hatches are occurring and the usually-secretive browns throw caution to the wind.

Evening is gathering and a Wilson snipe is whooping overhead when I finally see what I’ve been waiting for: a smoky olive mayfly comes bobbing down a golden riffle. Another green drake follows, and then another.

It was like someone flipped a switch – suddenly there are slurping noises up and down the creek. I need no further persuasion to join the fun.

The brown trout have come out from their undercut lairs and are lined up in the feeding lanes, smacking the hatching drakes as they float by.

They may be active, but that doesn’t mean they are totally vulnerable. The cast has to be soft and the drift drag free. Plus, you only get one shot. Mess up and they’re gone like campfire smoke. I lost a few, hooked a few and thoroughly enjoyed myself for the hour or so that followed, until the drake hatch ended, the trout stopped rising and the creek switched off once more.

This is why understanding the systems that make a small stream work is the most challenging, and rewarding, part of the anatomy. While it’s the physical elements of a small stream and the dynamics of the water that flows around, over and under them that defines it, it’s the interaction of the systems that makes it work. This connectivity between the fish, the angler and the food sources, both bugs and baitfish, is what binds everything together. The trout and grayling don’t always want to eat if the insects aren’t active, while other pressures in life mean a lot of the time the angler isn’t present during periods of high fish activity.

But when you do hook up and solve the riddle, at least for a few hours, it can be a lot of fun. The fish are feeding, but why? There are bugs hatching, but which ones are they? Likely the most important part of the anatomy of a small stream is the skill and ability of the angler to process all this confusing and conflicting information. Every new run, pool or glide presents a new set of problems and range of solutions. And no two streams, even in the same drainage, are clones.

But if angling really was as simple as shooting fish in a barrel, it would very quickly become boring and repetitive, the way a long, homogenous riffle on a big river can challenge your attention span.

This is the ultimate attraction of little water – the variety of opportunity and availability of choices. If you don’t like the pool you are fishing, there’s another one waiting around the next bend, so long as you have a fundamental comprehension of the anatomy of a small stream. And even if you don’t, it’s a great place to practice.

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