Trout smart 1

Trout smart 1Guest blogger: Mike Cline, Bozeman, MT

Years ago when I was fishing northern Minnesota every summer, I think I had a map of Lake Kabetogama in Voyageurs National Park from the Fishing Hot Spots map company. I couldn’t find the map when I looked recently but remember them as showing all the spots on the lake where the different species of fish should be found. I generally found fish in the spots they recommended but found them as well other spots. They still sell these maps and I guess they are useful in unfamiliar waters. They don’t make any of these maps for Montana so I guess there are no “Hot Spots” out here. But even without the maps, hot spots are an important part of fly fishing for trout no matter where you fish. I don’t know what the criteria are for recommending any particular location on a lake or stream as a hotspot, but I do know trout are smart enough to recognize a hot spot when they see one.

Of course I am not talking about hot spots marked on maps but those hot spots we add to our flies, those little bits of fluorescent thread, yarn, and floss or dubbing that somehow standout over the other parts of the fly. I’ve been incorporating “hot spots” in some of my ties for a while now, but wanted to learn more about where they originated and why they work. (Yes, they do work).

There’s a very good article on the topic in the Spring 2013 issue of Fly Tyer magazine. Hot Spots Make Flies Sizzle by Aaron Jasper gives a bit of history as well as contemporary knowledge on hot spots. Apparently originated by lake anglers in England in the 1970s there are debates about where the idea of hot spots actually came from. But there’s no debate as to why they are effective.

First, florescent colors reflect and hold their color much longer as flies descend the water column. Subtle and muted tones of black, olives and browns tend to wash out into a uniform gray as things get darker down deep. Whereas a brown fly might look gray at 10 feet, a florescent orange hotspot will still look orange (at least to the trout). This was the primary rationale behind the addition of hotspots—better fly visibility at depth.

Trout smart 2The second and most useful part of the hotspot question comes from the nature of aquatic insects, crustaceans and baitfish themselves and the way fish feed on them. Many living, if not most, living aquatic nymphs, pupae, emerging adults as well as baitfish have portions of their bodies that are sharply contrasted. Typically reproductive organs of female stoneflies often become bright red or orange before egg laying. Egg sacs of mayflies, caddis, etc. can be of color distinctly in contrast to overall body color. Internal organs may be of a distinctly different color than the exterior skin and show through segmentation or transparent parts of a body. This is especially prevalent in young baitfish fry. Leeches can display bright red, yellow, or orange spots or lines on their bodies. Molting crayfish have very translucent skins revealing contrasting internal organs. Reds and orange can be naturally found in midge pupae as blood is pumped to the wings prior to emergence.

Trout smart 3

What’s really important here are the theories as to why fish, especially trout in flowing water, react well to hot spots on our flies? Feeding fish are presented with a steady stream of drifting materials and potential food. Bits of wood, moss, vegetation, and other inert organic and non-organic materials are mixed in with all those living things—nymphs, pupae, emerging insects and baitfish. In other words, the trout has a choice. It is believed that instinctively, given the choice, the trout will choose things in the drift that most resemble food. Bits of wood, moss, vegetation, and other inert organic and non-organic materials generally don’t display any sharp contrasts in color, whereas living food does. Thus, so goes the theory, the addition of a hot spot to a fly influences the trout to at least examine the fly as potential food. It makes good sense, and as far as I can tell from my experiences, the addition of hotspots to flies does not detract from their appeal to trout.

If we look at this from an historical perspective, even though florescent materials weren’t really available until the late 20th century, anglers have been incorporating hotspots, at least in concept, to flies since the 19th century.

1882 Orvis Triumph
1882 Orvis Triumph

Even 19th century flies incorporated many bright colors and areas of sharp contrasts. The 1882 Orvis creation—The Triumph—was a highly successful bass fly. How many hotspots does it have?

A great many of the fancy wet flies of the late 19th century and early 20th century incorporated sharp color contrasts and bright or shiny tags of red, gold or silver that might be considered hotspots in their day.

Even modern classics such as the Woolly worm included a bright red tail or hotspot. The classic Royal Coachman is recognizable and probably so successful because of the red “hotspot” waist in all versions of the fly.Trout smart 5

Today we incorporate hotspots into our flies with florescent beads, dubbing, threads and such. And the one thing that has become obvious to me is this—there are no rules here, no precise patterns or dictums that say the hotspot should go here or there. Just about any fly, especially subsurface flies, can incorporate a “hotspot”–an element of high visibility and sharp contrast. Of course florescent beads are the easiest method, but subtle hotspots can be created with dubbing and/or thread. The great majority of my Woolly Buggers, regardless of color, are now tied with florescent orange thread which creates a small hotspot at the head of the fly. If trout are smart enough to choose between a small piece of moss and a bright green caddis pupae, then there’s no reason to make them think. Play on their instincts and give a “hot spot” to chew on.



  1. A very nice, thought-provoking article on hot spots Mike; I’ll pay more attention to this as I mess with and desecrate established/classic patterns on the vise.

    Regarding “thinking” and “intelligence,” I’ve always maintained that it’s just a matter of definition. We tend to define “thinking” as deliberate, hierarchical, if-then analysis and deduction, and we concede “intelligence” to creatures (a few beasts, a few humans) who can both learn in that manner and then leverage the same processes for making decisions.

    Myself, I tend to accept that *any* data path in a brain is intelligence, whether it was born in (instinct) or acquired through experience. And leveraging it is applying stored data to a question…therefore it’s a form of “thinking.” If I see a shadow slide past me in the stream at the corner of my periphery, I’ve seen neither eye nor fin nor gill, but based on motion and velocity I may decide it was a fish. I call it “thinking” that I saw a fish. And so if a trout sees a spot of red on a shape not exactly found in nature and decides it’s blood or an egg sac on food, I have to concede that as “thinking” too. That trout used a piece of stored data, and drew a conclusion. As you said, “the trout will *choose* things in the drift that most resemble food.”

    Well, again, it’s all just semantics, and my opinion. But as our politicos opine in the news nightly, we’re likely to agree that drawing faulty conclusions based on far-too-sparse kernels of data is certainly not behavior limited to salmonids….

    > fluorescent colors reflect and hold their color much longer as flies descend the water column

    Now that is truly fascinating (and a bit of data from which I can draw some conclusions…on which flies, and how deep to fish them). That point alone is very hefty, in my opinion.

    > They don’t make any of these maps for Montana so I guess there are no “Hot Spots” out here.

    I suspect it’s more like your entire state is one big hot spot. 🙂

    – Mike

    1. The question of fish “intelligence” is absolutely a matter of semantics, and, for the fly fisher, of personal angling philosophy. By Michael’s definition, fish do indeed think. But do they reason? Are they capable of abstract thinking, or deduction? I think not.

      From a scientific standpoint, based on comparative anatomy of the brain, fish simply do not have the equipment for this. Cognition and self-awareness occur in the frontal lobes of the brain. Humans have huge frontal lobes, which is why we are thinking organisms–although the results are sometimes questionable. The frontal lobes on a fish are so small as to be nearly non-existent. Instead they have a proportionally very large mid-brain, the location of the sensory array. In addition to keen senses, nature endows them with a formidible arsenal of instincts that helps them to deal with the imperative all wild creatures must face–be sufficiently bold to obtain enough food for survival, yet sufficiently cautious not to become food for another.

      Fish react to their environment, including the wiles of the angler, based on these gifts. When we are unsuccessful in our attempts to catch them, it is so tempting to go all anthropomorphic and believe that they are wily and intelligent. In fact we have simply failed to correctly deduce, and execute, what is required to exploit the fish’s instincts to our advantage. The late, brilliant Gary LaFontaine wrote of positive and negative triggers. When the positive triggers outweigh the negative, the fish eats. When the negative triggers outweigh the positive, the fish does not eat. It’s just that simple.

      What’s not simple, in many cases, is figuring out what we need to do to make that equation come out in our favor. The complexity of that endeavor is what makes fly fishing so endlessly fascinating, and something we would never want to lose. The great paradox of the sport is that we spend so much time and effort trying to reduce it to a science, but if we were to succeed we would destroy what we love. If fly fishing ever became completly predictable and controllable it would be a crashing bore and we’d all go off looking for another, more interesting pastime.

  2. Eloquent and well considered as always, Mary; I enjoyed your thoughts very much.

    This whole topic might be a long-held vexation with me, so I’ll try to put my own final lid on it, FWIW, and then shut up.

    Involved in the field of “deep learning” as I am, I have a bit of a feel for (some peoples’) formal definitions of abstract reasoning, and for the complexity of the “engine” capable of running very simple “reasoning” algorithms and of making simple or more elaborate decisions based on stored bits of data. A single pair of “flip flop” cells in a circuit can compare a new input to stored data and draw a conclusion–and feed that into the “choices” of thousands of other flip-flop pairs. Ditto biological brain cells. So unless there is literally no processing engine at all, the extent of decision-making (especially pattern recognition) ability is really just a matter of degree. The agreed-brilliant Gary LaFontaine’s “trigger” explanation describes a simple choice-making mechanism in that very light.

    I think you and I are in total agreement that trout frontal lobes will be weak decision-making “reasoning” engines. Again, to me it seems mostly a matter of degree–there has to be a very little bit of this-or-that choice-making there, but nothing on the scale we humans leverage, or even acknowledge. (And possibly elephants, orcas, saucer-flying aliens and Supreme Beings…and readers tired of this debate…are right now saying the same thing about me.)

    > the imperative all wild creatures must
    > face–-be sufficiently bold to obtain
    > enough food for survival, yet sufficiently
    > cautious not to become food for another

    So incredibly well expressed! I’ve been dabbling in salt water angling lately, and in subsurface observation in the Hawaiian islands; my most powerful recent impression has been how much predation occurs in the sea, and how carnivorous and ruthless a world it is…how thoroughly any creature must risk its own life in order to feed on that of another. It’s an “instant karma” system, philosophically (and savagely) fitting and beautiful in its way. Makes me glad I’m a dry land mammal who knows how to farm and build walls.

    Thanks again Mary (and Mike too), for the poignant exchange and food for thought.

    – Mike

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