Cartoon by Peter Kohlsaat

“Fish riprap on a sunny winter day because rocks warm the water,”says a pro.

Ever sit on a chunk of granite on a cold day? Cold, eh? Why would a rock warm any more or any faster than a clay, gravel, or sand bank? Now a dark, algae-covered rock is a different story—it absorbs more light than a light rock and heats more. Heat happens when something absorbs the energy of sunlight.

More conflicting information on warming water from articles that quote professional anglers:

Pro A: “I look for turbid water in early spring because it warms faster.”

Pro B: “In early spring, I focus on clear, shallow pockets because the sunlight reaches and warms the bottom, and that warms the water.”

After some reading and discussions with limnologists, it seems to boil down to the dark rock principle—heat happens when light is absorbed. Suspended particles in turbid water absorb light and warm surrounding water. In clear water, light that’s not absorbed in the water column will be absorbed by the bottom, so the bottom, too, can generate heat.

But shallow water is constantly mixing, so it doesn’t matter whether the heat is generated in the water column or on the bottom. In other words, it doesn’t matter whether the water is clear or turbid. Another important note on clear water: If you can see the bottom, that means that light is being reflected back out of the water and is “wasted” in terms of generating heat in the water column. So, muddy up the water and fish it tomorrow.

Bass Porn

From an article on bed fishing: “The male bumps the female to loosen the eggs.”

Bass courtship and spawning rituals can get a li­­­­­­­ttle rough, but it’s not to loosen the eggs. Hatcheries go out of their way to give brood fish a lot of TLC, and female bass drop their eggs without being bumped, nudged, or battered.

Getting Light-Headed

Another environmental condition that affects bass behavior is light. Light, or more specifically what affects light transmission—water clarity—is fertile ground for anglers’ cogitation and writers’ prose because clarity constantly changes, challenging the Holy Grail of fishing—getting a bite. I like clear water, and it surprises me that some anglers actually seek turbid water to catch bass, given their nature as sight-feeders. I guess cashing some of those big tournament checks by fishing mud would make me change my mind.

Biologists don’t know how much light bass prefer because it isn’t something they can control to create better bass populations, so it’s not studied. But anglers fully appreciate the importance of light and water clarity in determining where, when, and what lure colors to fish. Due to the importance of water clarity, anglers have developed their own scale for measuring it. If you’re a student of water clarity you probably know there are several such scales.

One is the murk scale; water ranges from clear to very murky with intermediate values of slightly murky and rather murky. Another is the stain scale, also with intermediate values. Then there’s the stain-murk scale where water ranges from clear to various degrees of stained, followed by several degrees or murkiness, finally ending at mud. Bass anglers weigh and measure their bass, dwell on water temperature, and obsess with boat speed. Is there some reason they don’t measure light or water clarity?

One successful (and rich) tournament pro does measure water clarity. He states, “Determining water clarity is essential in making this pattern produce. I judge water clarity by slowly lowering a spinnerbait into the water. If I can see the lure at 4 inches or deeper, I call that water ‘stained.’ If the lure disappears at less than 4 inches, I call it ‘highly stained.’ And if the lure disappears immediately when it hits the water, that’s ‘muddy.’ With this system, I can compare water clarity in different spots, and when I get a pattern going with a particular bait and water color, it gives me a way to extend that pattern to other areas.”

Another highly successful (and also rich) tournament pro writes that, “Clear water” is a relative term.” (Amen to that.) To resolve any possible confusion, he notes, “Clear water is where I see a lure in water deeper than a foot and a half, stained water is where I can see a lure from 8 inches to a foot and a half, and muddy water is where I can’t see my lure in 8 inches.”

Obviously, these two anglers don’t need to be swapping information. For us less-creative anglers, how about we just note clarity in feet and inches? For example, there are times when I can see a white spinnerbait 30 inches below the surface. Maybe that’s not the right culture-speak for the boat dock or the weigh-in stage, however. Somebody might think you work at a university or something. But measuring water clarity in inches is useful if you’re one of those fact-loving anglers who keeps a fishing log. An inch will be an inch five years from now, whereas the definition of stained and murky may change based on the next how-to article you read.

One more misconception about light in water: “Fish a spinnerbait in the twilight zone, the depth where it just disappears from view.” Like many of the tips relayed by sage fishing writers, this one often works. But why? Because if you can’t see the bait, bass can’t see you. Right? Wrongamundo. For you to see a spinnerbait, light must pass through the water, reflect off the spinnerbait, and travel back to the surface. But the vision of bass is entirely different, and fortunately for them, far better than ours.

I’m not aware of studies that measured the minimum amount of light bass need to see objects, but as a general rule, fish can see at one-tenth the light we need to see. Because of the properties of light in water, bass can see a spinnerbait at approximately four times the depth at which you can see it. Try to figure that depth out using the stain or murk scale.