Trout are extremely wary fish. They are wary of movement, wary of noise, wary of what we cast at them, and probably even wary of human scent.
Their senses have been sharpened by a long evolutionary path in habitats that expose them to predators from the air, the land, and from within their own aquatic environment. For anglers, the legendary ability of trout to pick up minute signs of danger and vanish within a blink of an eye makes them one of the most challenging sport fish.
Brown trout, one of the two main trout species inhabiting most of New Zealand’s rivers and lakes, are generally considered the warier, although rainbows can be frustratingly difficult to deceive at times, too.
Globally, the most popular angling method used to target trout is fly fishing. Paradoxically, it is also the most difficult, complex, and, depending on where you practice it, the most expensive. My best explanation for such a contradiction is that fly fishing for trout provides anglers with a never-ending learning path towards perfection.
It follows that your success as a trout angler will be directly related to how well you understand and how well you can deceive the formidable senses Nature has so generously bestowed upon the trout. This article alerts you to some of the pitfalls faced every time you pick up a fishing rod.
Trout can be spooked in many ways, but for ease of understanding I have broken the causes down into two categories: the behaviour of anglers, followed by fishing equipment and how it is used.
Stealth: Perhaps the most critical aspect required for achieving successful fly-fishing is stealth: anglers must keep their movements quiet, slow and unobtrusive as possible. The following aspects expand on this topic.
Outline, colour and movement: Years of fishing in many parts of New Zealand have convinced me that a resident trout is familiar with its surroundings, both in-stream and on land. Any sudden changes are noted, especially changes in colour and structure. It might be an unusual shadow, a new outline (perhaps of a different colour), a moving object, a silhouette that was not there before – all are registered by trout and responded to with apprehension, if not outright alarm.
Making things more difficult still, these changes can be picked up within a visual arc of 270 degrees, theoretically leaving a blind-spot wedge of only 90 degrees behind the trout’s head. Also, because a hovering trout oscillates from side to side, this ‘blind wedge’ may well be narrowed even further.
Like many other fish, trout have a lateral line of sensors on either side of their bodies that alerts them to minute vibrations in their general environment.
I recall an incident on a small stream running through a dairy farm. When I approached a pool I knew held a good brown trout, several cows were grazing on a raised bank in full view of the fish. To my surprise, the fish was busily feeding under the run-in foam line, but bolted as soon as it saw my outline moving among the cows, despite my ex-army camo jacket. I can only assume that this trout learnt to distinguish between the horizontal silhouette of cows and the vertical silhouette of a human.
We humans can pick up bright and contrasting colours much more quickly and easily than colours that blend with the general background. It would be naive to think that trout can’t do likewise.
Gone are the days when soldiers wore bright-red tunics. Modern armies dress their troops in camo pattern uniforms that reflect the general background colours: blocks of beige and brown for arid landscapes, brown, black and green for jungle warfare. Camo patterns not only blend with the background, they also break up the outline of an otherwise solid object.
Blending into the background is equally important for the serious trout stalker.
Sound and vibration: Sound travels well in water, so noise generated when wading often alerts trout long before they come into view. Stones crunching under foot, anglers pushing a noisy bow wave, or the scratching of tungsten studs on boulders, can all put wary trout on edge. Chances are, when you finally see them they have already stopped feeding and are only waiting for one more confirmation before dashing for cover.
Stealth means making way slowly and quietly, blending into the background and staying as much as possible in the trout’s visual blind wedge.
Scent: If you consider that trout can remember the scent of the stream they were spawned in, finding their way back to it several years after they hatched from an egg, it should not surprise you if they also pick up the water-borne scent of your insect repellent, sunscreen or body odour when fishing downstream with bare legs.
I used to fish one small Taranaki stream so frequently that I knew most of the resident brownies by name. Fishing upstream I would expect to see around 20 trout, and this number only varied slightly during repeated visits. However, when I criss-crossed the stream on my return to the car several hours later, I hardly saw any fish, despite looking carefully.
The question is: were they still hiding when I spooked them on the way up or did they take cover after smelling my scent carried before me by the running water?
On a visit to the Ngongotaha Hatchery I recall the manager saying that the young fry go off their food if it is contaminated with a stranger’s scent. Makes you wonder, doesn’t it?
Rod flash: Years ago, when I lived in Hawkes Bay, I regularly fished in the Tukituki River. One sunny afternoon I saw repeated sun flashes on the edge of an upstream pool. Only when I got closer could I make out an angler casting his rod.
When we eventually met, I noted he was wearing drab clothes that blended perfectly with the grey gravel of the riverbed. Not so his rod, which sported a highly-polished paint job that reflected the sun’s rays like a mirror. He was quite shocked when I told him that I had seen his rod flashing from two pools downstream.
As I build most of my fly rods from blanks, I always leave them in their natural matte-grey-graphite finish.
Fly lines and indicators: When casting to a sighted fish, I try to keep my fly line out of its view. But I know that is not always possible, so use drab-coloured fly lines that look less alarming.
A few years back I hit upon the idea of camouflaging the first five metres of my fly line by dunking half the coiled line in a warm fabric dye. The result was spectacular, with a darker-green section alternating with a light green one every foot or so, breaking the outline most convincingly.
I really thought I was on a winner, until I used it on the Tongariro. What a shocker! As soon as the line moved, the darker sections became highly visible – like a convoy of individual trucks moving on a road. Quite recently a line company did the same thing to ‘stealth proof’ one of their lines, but I’m not buying it…
But a fly line or indicator does’t have to move to make fish wary. In clear and shallow water, just drifting over fish can put them on the alert.
The signs are often quite subtle. Whereas before fish confidently swerved from side to side, an alerted trout ranges much less. In such situations, it only takes another badly-placed cast to stop the fish ranging altogether and to freeze on station. We used to call such motionless fish ‘stiffies’. Sometimes they drift back to investigate, but eventually they play safe and head for cover.
Like glossy rods, high-visibility fly lines can also spook trout when snaking through the air during repeated false casts.
Generally speaking, trout are more sensitive to disturbances from above than below. A dragging line or indicator skating across the surface is just as damaging as repeated water hauling during a false-casting sequence.
Only last winter I found myself stuck behind a guy doing the Skagit thing with a double-hander on the Tongariro’s wide-butshallow Lower Bridge Pool. First, he ploughed the quiet water setting up each cast, then dragged a finger-thick floating head across the surface of the slowly moving current. Needless to say, those of us fishing behind him failed to get a single strike.
By contrast, sinking lines are far less intrusive. Most are very thin and coloured black, grey or green. Trout tolerate such sub-surface lines better because they more closely resemble the debris seen drifting past them all day long. When cast through the air, such lines are all but invisible
At the height of the spawning run, the Tongariro River is stacked with fish and its banks lined with hopeful anglers. Such spawning-run fish are said to be naive and easy to catch.
Yet there is a pattern that hardly changes from year to year. The best fishing happens when the river comes down after a fresh and the water is a milky-green, with the thickest of the cream going to the first angler fishing though a pool after daybreak. Later in the day and/or when the water starts to clear, the fishing gets harder. Why? Have all the fish been caught, or have they moved on? Hardly, because drift-dives confirm plenty of fish still present. The most plausible reason for the lack of action is that these ‘dumb’ fish have wised up to the procession of Glo-bugs, dragging lines, budgie-sized indicators and deep-wading anglers!
If lucky enough to find a pod of fish lying tightly packed in clear water, you might think that these fish are now at your mercy. In my experience though, one of two things will happen: the fish will either bolt into the white water or, as I have also seen it in the Lower Tauranga-Taupo River, drift apart to let a Glo-bug pass through them unmolested and then join up again. It is therefore a real blessing for my mental health that I can’t see just how many fish pass up my offerings on the much larger Tongariro!
Everything I have written above indicates that trout fishing is a battle of wits between a creature with a pea-sized brain and the pinnacle of biological creation. Humiliatingly, most often the trout comes out on top. However, when you think about it, getting cut down to size every now and then is just what we humans need.
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