The Colors Bass See
The color of a lure is distinctly different underwater than it is in a boat. Why is this? Because of how light reacts with water. The sun’s rays heat the water of a lake. That is, the lake converts light energy into heat energy. Stated differently, the lake absorbs the light and turns it into heat. But water absorbs some colors much more readily than other colors. The sun shining on a lure in a boat contains all color wavelengths. Not so once these color wavelengths enter water because the water is a biased absorber of light. Reds are turned into heat first and blues are absorbed last.
This is why natural underwater scenes are so blue. In perfectly clear water all shades of red are absorbed and converted to heat before the light reaches 17 feet of depth. Next to go are the various shades of orange. Orange gradually turns to a dull yellow as an orange lure runs deeper and deeper. After the oranges are gone the yellows are filtered out next. And greens follow the yellows. And finally nothing is left but blue light. After the blues are absorbed there is no light — only darkness. Just before the blues are absorbed everything appears in various shades of dark blue or black. A white lure will look white in the first few feet of water, but it gradually turns green then blue as it goes deeper and deeper. A bright red lure will appear bright red in the first few inches of water, red for a few feet, then at deeper depths it gradually turns black. Why? Because no red light reaches the lure to shine on it. These words apply to color without regard to the eyes perceiving the color.
Eyes have cones and rods
Bass evolved along a totally different path than humans. From an evolution standpoint there is no similarity between how a human thinks and a bass thinks. There is little similarity in how a bass hears and a human hears, and we have to be careful when we are comparing how a bass sees and how humans see. Bass eyes evolved to see in water. Human eyes evolved to see in air. But there are striking similarities in how a bass eye works and how a human eye works.
Cones see colors; rods see things in shades of gray. As best we can determine, a bass sees colors much as a human sees colors. We think this is true because bass eyes have cones very similar to the cones in human eyes. But here is one huge difference: A human eye has a pupil, a bass’s eye has no pupil. In bright light the human pupil closes down. In dim light the human pupil opens up.
But, since a bass eye has no pupil, it adjusts to brightness by repositioning rods. In bright light a bass sees with cones with almost all of its rods being hidden behind cones. As the light dims more and more rods are positioned for sight. In really dim light cones are less effective and the bass sees primarily with rods. Thus, in really dim light a bass sees in black and white. And a bass’s eye has better (and many more) rods than does a human eye. Thus it sees in dim light much, much better than does a human.
Remember: cones see colors; rods see shades of gray. This means that in shallow and clear water a bass sees in vivid colors, but in deeper dingy water it sees dull colors but mostly it sees shades of gray. A bass can see six or seven times better than a human, but most of this increased visual acuity is in dim light. In other words, most of this increased vision is in black-and-white.