Most tackle boxes are bulging with lures of every hue, and each fishing trip becomes a study of what color lure will entice the fish today. Certain principles of vision and the behavior of light as it penetrates the water can make lure selection more scientific. Do fish see color? Studies have shown that trout and salmon have color vision similar to that of humans. Most fish can see in color. As in humans, the retina of a fish’s eye contains two types of cells, rods and cones. Trout and salmon can distinguish complementary colors and up to 24 hues.
Determining what colors are visible at various water depths is literally a science. There are many factors that affect how light penetrates water. Flat calm water will reflect a large fraction of light. On choppy days and on wavy days light penetration is diffused and scattered.
The most common factor that changes the penetration depth of light in water is the amount of light available. If it’s cloudy and dark there is less light available to enter the water. Light angle plays a significant function in light penetration. As the sun rises and sets, the light will be hitting the water surface at different angles. Most light penetration occurs during the most direct sunlight period when the sun is closest to a 90% angle to the water surface. At angles of 40% or less light penetration lessens. Water clarity also affects light penetration and color absorption. The clearer the water the deeper all wavelengths of light will reach. Turbid water due to sediment, algae or other factors, inhibits light penetration and influencing color absorption.
Under perfect conditions, red and oranges are the first colors to disappear followed later by yellows, greens, purples, and blues in that order. Red light is almost completely absorbed within the first 15-20 feet. Orange penetrates to 30-40 feet, and yellow to 60-70 feet, while green and blue remain visible for as deep as the light penetrates.
How does this apply to fishing? If you’re running red or orange lures or flashers and running them below 20 or 30 feet then the color is not showing, these colors are showing as brown or black. This means that if you’re having success with these lures it is not due to the orange or red color, it may be related to the action or flash. Fluorescent colors have the added advantage of reflecting ultraviolet. Trout and salmon can see into the ultraviolet range well beyond human capability.
I fished Pyramid Lake, Nevada with my grandson and son-in-law on April 20th and 22nd.
Changes were in store from strategies of previous trips this winter and spring. Water temperature is on the rise as the first day’s trip saw a rise in surface temperature of nearly 4 degrees from morning until that afternoon. With longer day length and greater light penetration, fishing at 5 to 10 feet was less of an option. Large growths of moss were prevalent at these depths causing lures to be encased in the slimy vegetation and thus non-functional. We opted for deeper waters. We fished from 20 to 40 feet and managed to catch and release 23 Lahontan cutthroats ranging from 19” to 231/2. Lure selection and the change in fishing approach were the keys to success. Size #4 Lyman’s and U-20 flatfish in gold chrome (sparkle) and copper were used.