By Mike Schoonveld
King salmon can see color quite well. Nearly every chinook angler has proved that personally by observing how some days the kings will readily attack lures painted a certain color but will snub similar lures of a different color.
Sometimes color only serves to make lures more visible. Anglers in areas where water clarity is diminished know a bright chartreuse or hot-red lure is likely to elicit more strikes simply because the fish can see the lure more easily. Glow-in-the-dark lures often work well in dim light conditions because they shine against the dark background.
Sometimes lures that match the prevailing forage work the best. The salmon are keyed in on eating silver-sided 4-inch alewives, and silver 4-inch spoons are the hottest lure in the lake. At other times, nearly the opposite game needs to be played. When fishing around massive schools of baitfish, a winning ploy (sometimes) is to use a lure that looks different enough to attract attention away from the thousands of real minnows in the school. A silver spoon might go untouched, but replacing it with a purple one allows the salmon to pick it out of the crowd.
Finally, some colors seem to excite fish and goad them into biting. A perfect example is that steelhead are suckers for a bright-orange-colored lure. It doesn’t matter if the water is clear or stained, and it matters not if there are a lot of baitfish around, because there’s nothing swimming around in the Great Lakes that is this color, so it’s not a preference born of experience. But show a steelie a bright-orange spoon and it’s yours – most of the time. With chinooks, I’d pick a bright green color over most other hues.
Knowing these four “color theories” makes a person a better angler. Out on the lake, however, when it comes to color, what you see isn’t always what the fish see. Let’s review an experiment I remember from my seventh-grade science class.
On a sunny day, Miss Kroft closed all the shades in the schoolroom, including one with a small hole in it. The sunbeam that came through that hole was directed to a white movie screen and we all agreed that the light on the screen was white. When the teacher positioned a prism in the path of the sunbeam, the white spot of light on the screen transformed into a multitude of colors – a rainbow of colors, one could say – since rainbows are prismatic arrays on a giant scale. The colors that showed on the screen were red, orange, yellow, green, blue, indigo and violet. Miss Kroft taught us to remember those colors by remembering the name Roy G. Biv, with each letter of Roy’s name corresponding to a color of the rainbow.
According to the science lesson, these colors make up the visible spectrum that humans are able to see. All the colors we see are combinations of these seven colors.
Why is a stop sign red? When sunlight beams down on the sign, all the colors of the spectrum are hitting the red paint. All of the colors are absorbed by the paint, except for red, which is reflected and that’s the color our eyes perceive. Green-colored grass absorbs all the colors of the spectrum except green, which it reflects and we see grass as green. Write this lesson on a clean blackboard and we see the white-colored chalk marks as white because the chalk reflects all the colors of the spectrum back to our eyes while the blackboard absorbs all the colors, reflecting none, and we see the absence of any color as black.
This science lesson might be interesting, but how does it relate to fishing for salmon or trout on the Great Lakes (or any fish for that matter)? Not much until you factor in the color-filtering properties of water.
Again, let me take you back to my school days, this time on a field trip to a place where we could view divers working underwater, thanks to a glass window in the side of the tank where they were swimming. Two of the divers swam to the window to give us an easy view of their swimsuits. One wore a red swimsuit and the other wore blue swimwear. As the divers retreated toward the rear of the tank the red-colored swimsuit darkened, and by the time the diver was 15 feet away from the glass, the swimsuit looked as though it were made of black cloth. In contrast, the blue suit still looked blue.
The lesson learned was this: As visible light passes through clear water, the water molecules absorb some of the light, but they don’t absorb all the colors of the spectrum equally. The colors at the top of the spectrum are the most easily absorbed – the red, orange and yellow components. The ones at the bottom are the most resistant to being absorbed – the blue, indigo and violet light. By the time the red reflection off the red cloth passed through 15 feet of water, all the red was absorbed. No more red light – our eyes saw only black.
So let’s take a fish’s-eye view of all this science. Imagine a fish swimming along about 25 feet below the surface. Up above let’s put an angler who will lower a red lure down to the fish’s depth. Above that, let’s have the sun beaming its white light down into the lake. As the sunlight penetrates down into the water, the red portion of the light starts being absorbed, and from the example of the red-suited diver, we know that all the red part of the spectrum is filtered out in the first 15 to 20 feet of water. Therefore, there is no red light left to reflect off the red surface of the lure; the red paint absorbs all the other colors of the spectrum and so the lure appears black to a fish.
Orange light is absorbed next. In perfectly clear water, there may be enough orange “energy” left for an orange lure to be seen at 40 feet, but figure that your best orange-colored lure will lose its color somewhere in the 30-foot range. Yellow light will persist as deep as 60 to 70 feet, while water filters green, blue, indigo and violet parts of the spectrum poorly and those colors will remain visible on down into the depths.
These figures are for lures painted with conventional pigments, but glow-in-the-dark and fluorescent pigments don’t play by the same rules of science.
Luminescent (or glow-in-the-dark) lures are covered with a paint or a taped-on appliquÃƒÂ© that makes them glow. Without trying to explain why it works, the how is simple. The glow tape rapidly absorbs a quantity of light energy (from the sun, a flashlight, a camera strobe) and then slowly releases the light over a period of time.
Water depth has nothing to do with this process. But since conditions darken as water depths increase, anglers
may find lures that glow or lures with glow highlights work better when fishing at extreme depths, on cloudy, dark days or early in the morning or late afternoon.
Fluorescent colors are somewhat similar in that they glow, but the physics behind the glow is different. Instead of fluorescent pigments storing light energy and releasing it over time, the fluorescent properties react to being hit with light energy by “glowing” or producing light. Turn off the light source and the pigment stops glowing instantly.
The trick is to look at a lure and decide if it’s been painted with a bright hue of conventional paint or painted with fluorescent paint. The best way is to purchase a “black light” bulb and view your lures in its light. Most of the light these ultraviolet bulbs produce is outside the visible spectrum, so human eyes don’t see it. Still, the light energy is there and will cause the fluorescent pigments to glow. The results will be surprising to you. Many of the lures and lure highlights you may think are fluorescent are merely bright paint.
Since both fluorescent-painted lures and glow-in-the-dark lures actually radiate light, instead of merely reflecting light, depth has nothing to do with the color of the lure – only the brightness. A glow lure may appear brighter as the lure descends to the dim depths; a fluorescent red lure will still appear to be red, but the brightness will diminish as the amount of light penetrating deep water decreases.
Now that you’ve had your science lesson for the day, school’s out and it’s time to put the knowledge to work. Grab your gear and head for the lake. This time instead of choosing your lures wisely, choose them scientifically – or at least with an understanding of the science that makes them work.
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