Tenkara High Lake Strategies III - Trout Vision Systems and Its Angling Applications
Questions And Answers About The Reasons For Fishing High Contrast Fishing Lures:
Why did Mepps make such a big deal out of the high contrast some of its spinning lures showed under the blue, green and reddish-brown water color conditions showed in the photographs of their spinning lures in the article I gave the link for in Tenkara High Lake Strategies, section II? Is not the whole object of fly fishing to make a fly that imitates as much as possible the appearance and actions of a natural food form insect that the fish are feeding on in order to catch that fish?
Actually, in many ways, exact imitation can be more of a hindrance than it is a help. Mountain lake trout feed opportunistically rather than selectively more than 90% of the time. If you have 1,000,000 bugs out on the water, and you throw out an exact copy of one of those bugs, what are the chances of your fly being taken? Answer, about one in a million. But put the fly equivalent of one red apple in a whole basket of green apples, or one blond in a whole auditorium full of brunets, and we can increase the odds of our fly getting taken, dramatically. Most of the time on the high lakes, you will not be fishing to a hatch but be putting flies out there that are plausible representations of insects that could or should be present at that time of the year. And the trout are usually happy enough to feed on what ever they can find to eat, so the fish are not too choosy about what they will take as long as you make good presentations to them. You always have to do your part.
What Were The Highest Contrast Color Combinations In Mepps Photos?
Answer: Black, with purple coming in not too far behind, white and silver were the colors that showed the most consistent high contrast in the 3 photographs of the blue, green and red/brown stained waters. Once we understand a little more about how the trout's visual system works, the reasons for fishing high contrast fly patterns (and their uncanny effectiveness) will become much easier to understand. You see, trout do not see nearly as well as we commonly give them credit for. The average human has 14 times as many visual cells packed on his retina as a trout does. The trout's visual images are comparable to an old, snowy analog TV coming in with poor reception, compared with a new digital HD TV picture on cable. The rods and cones on the trout's retina work a lot like a microprocessor works in binary mode - Go or No-Go, predator or prey, eat or run for your life. Things like rocks in the water, water weeds, and the color of the ambient space light background in the water, while seen, are hardly noticed or register on the trout's brain in a cognitive way. Trout are programed and hard-wired to visually detect contrast, patterns, and movement. If any one or more of those things enters the trout's field of vision, chemical impulses are instantly transmitted through the optic nerve to the trout's brain, where preprogrammed behaviors are acted upon that automatically excites the brain in one way or another. Water is a dark and gloomy environment where things happen quickly. Trout have to react quickly to get food and survive. They do not have time to ponder their options the way we can. If the object of interest is too small to eat the trout in question and is acting acceptably, it will be investigated as a food source. And if it falls within the acceptable range of other known food forms the trout has eaten in the past, it will most likely get eaten this time as well.
High Contrast Fly Tying Materials:
For centuries now fly fishermen and fly tiers have known that high contrast variegated fly tying materials catch more fish than solid colored hackles and furs do. High contrast materials like grizzly hackle, mallard, teal and wood duck flank feathers, grouse and partridge hackle, hare's ear and squirrel fur dubbing are much more effective than comparable solid colored materials are. Why? Because of the patterns of high contrast inherent in these materials provide appeal to the preprogrammed visual machinery the trout possesses. Aquatic larvae, nymphs and pupa all take on the color of their surroundings to give them protective camouflage to help prevent the trout from eating them, but the camouflage usually includes dark to black speckling and baring in the color combinations used, which the trout has the ability to easily and quickly see through, undoing all the aquatic critters hard work to save them selves.
Ultraviolet Vision In Trout:
Like us, the rod cells on the trout's retinas are used for low light, black, shades of gray, and white vision at dawn, dusk and at night; the cones are responsible for color vision and seeing fine detail under normal daylight conditions. But in addition to those two retinal cells, the trout also have UV-light sensitive retinal cone cells that allows them to see nearly as well as we can see in daylight conditions during periods of cloudy weather, at dawn and at dusk, and on moonless nights. UV-light is not filtered out by cloud cover and water depth the way that visible light is, penetrating to more than a mile deep in the ocean where it is that deep. Many of the trout's food forms also light up like tiny lanterns in UV-light, so UV-vision is a great aid in food procurement for the fish that have it. Unlike the trout, we humans are totally blind to Ultraviolet light. Many insects (but not all) and birds have UV-vision and UV markings that are species and sex specific for breeding, and also for food procurement purposes, so there is a whole world of activity going on out there that until recently we have been totally unaware of. Flies tied with the right amount of UV-materials used in their construction (placed in the right places) are considerably more effective than flies tied without those materials and considerations. This has been accomplished to some extent in the past purely by accident through a trial and error process, with no one knowing for sure just why the flies were successful.
The Trout's Primitive Brain:
Trout have very primitive brains that are 1/5th size of a comparably sized mammal's brain, which should be a sure indication that trout are not too bright. There is no cerebellum in a trout's brain at all, just a brain stem with 5 parts, the largest of which is the optic lobes. For sure trout have the senses of smell, hearing and touch, and they can locate prey with these abilities under poor visibility conditions through lateral line sensitivity as well. But trout are primarily visual hunters and feeders, always depending on a visual lock on to make the final kill, so our flies should always appeal as much as they possibly can to the trout's visual capabilities, abilities and programing.
Salmonoid Color Vision Shifts:
When salmon and steelhead roam the oceans, their vision is attuned to the blue through violet end of the spectrum as most of their prey and predators are green in coloration, coming out of the deep blue sea depths. But as they approach the rivers to make spawning runs, their color sensitive retinal cells change to be sensitive to the red/orange part of the visible spectrum. Trout are not as pronounced in their color vision shifts as the ocean going salmonoids are, but they do show aggressive tendencies toward fly patterns with red, orange, hot pink and yellow while exhibiting spawning behavior and they are in their spawning colors.
Of All The Qualities A Fly Pattern Can Have, Motion In Its Tying Materials Is The Most Important One To Have:
The trout's sensitivity to motion in fly patterns is arguably the most important condition for the angler to meet and respond to. This does not mean the simple motion of the fly being retrieved through the water but the breathing, swimming, quivering motions of the soft, pliable materials that the fly should be tied with. The pulsating actions of the materials on the hook automatically transmit a message of excitement to the trout's brain when its eye or eyes see the motion. For sure the brain can override the excitement, the strike is not an automatic, given result. But exciting the trout's brain to that extent puts the angler well on his way toward success, and is surely much farther along on the road to success than a hard, stiff, more realistic looking fly pattern that has no material motion will ever get.
Fly Patterns As Cartoons:
A fly pattern should be a characterization of the food form being imitated, including one or more of the necessary triggers that elicit strikes, as well as the confirming characteristics that seal the deal when the trigger, all by itself, is not enough to do it, with out the inclusion of all the confusing details of all the anatomically correct body parts that the insect or animal has to offer. Such impressionistic fly patterns often do not look very realistic in the fly box or in your hand. But in the water, given the proper animation, they come alive and are extremely effective fish catching patterns. A pattern should never be judged by its appearance out of the water alone. See what it looks like in the water when given the proper retrieve before you reject anyone's fly pattern out of hand.
It is hoped that this brief review of the trout's visual systems and its abilities will help you to buy and/or tie more useful and effective fly patterns for high lake Tenkara fly fishing. I am sure many things have been brought up here that many of you may have never heard of or seen before. If you would like to get more information on these subjects, and more, I can recommend the following books. HOW FISH WORK, Fish Biology & Angling, By Thomas J. Sholseth, DVM, MPVM, Frank Amato Publications, Inc. and THE NEW SCIRNTIFIC ANGLING, Trout and Ultraviolet Vision, By Reed F. Curry, Buckram Publishing.