Water clarity is one of the most variable and unpredictable aspects of bass fishing. Unfortunately, it's also one of the least understood. While any bassman worth a spinnerbait skirt realizes that changes in visibility affect bass behavior, few use it to their advantage. Sure, savvy anglers adapt to seasonal conditions to help zero in on productive patterns, but the only go-to muddy water solution I've heard is "find clear water." Good advice, but it may not be an option when it rains three inches two days before your planned trip, and everywhere you go the water looks like chocolate milk with extra chocolate.
Fishing For Answers
Understanding the effects of water clarity starts with understanding bass. They are primarily sight feeders, so water clarity's effect on fishing makes sense. Vision increases a predator's chances of detecting and capturing prey—especially moving targets. Yet, even though fish can see at lower light levels than humans, they still need some light to visually detect prey.
When clarity is reduced, so are the distance and depth at which bass can see. Along with light levels, clarity helps dictate the depth below which sight feeding is futile. Not surprisingly, serious anglers have long pondered whether there is a "magic" depth for catching muddy-water bass.
Dirty Water Data
To explore the relationship between water clarity and the depth at which fish are caught (catch depth), I asked three accomplished anglers—Timmy Horton, Ron Shaw and Roger Stegall—to be the "field technicians" for a little research.
Horton, BASS Angler of the Year and seven-time Bassmaster Classic qualifier, fishes waters throughout the eastern U.S.
Shaw, an Oklahoman, is a consistent top-10 finisher in BFL tournaments and winner of the 2005 Fort Gibson event. Over the years he has learned to consistently pull bass from the often-turbid reservoirs in his home state.
Stegall, a guide on Pickwick and Tennessee-Tombigbee Waterway lakes in northeastern Mississippi and northwestern Alabama, has nine top-10 finishes in FLW and Bassmaster tournaments.
The experiment was simple. From early spring through summer, each of the men fished different waters—with different preferred patterns and different catch objectives—under a variety of conditions.
Along the way, they dutifully recorded both the water clarity (see "Measuring Water Clarity" sidebar) and catch depth. In most cases, the latter was a range of several feet, so I used the deepest depth they recorded for consistency.
Crunch Time
When all the final numbers came in, I used a technique called "regression analysis" to determine if the relationship between water clarity and catch depth was positive (depth increases with clarity) or negative (depth decreases with clarity). I also analyzed the probability of predicting catch depth from clarity.
Using combined data from all three anglers, I found a positive relationship between water clarity and catch depth. The clearer the water, the deeper bass were caught. Although the relationship was significant, there wasn't a specific depth at which everyone caught fish at a particular level of clarity. So predictability of a "hot" depth was low.
Because each angler fished different presentations and patterns, I crunched the numbers for each man separately. Across the board, the relationships were positive. And for Horton and Stegall, the likelihood of predicting catch depth from water clarity was high.
Still, the experiment had yet to provide any significant information about precisely how deep to fish at a given water clarity, so I tortured the data more. I calculated an index of catch depth relative to water clarity. Let's call this the "catch-depth-to-clarity ratio."
I discovered that 55 percent of the time, Horton caught bass at depths less than twice the water clarity, and 90 percent of the time, his fish came from depths less than four times the water clarity. In other words, if clarity was three feet, almost all of his strikes came from within 12 feet of the surface.
Shaw had similar results. Sixty percent of his bass hit at depths less than three times the water clarity—80 percent at less than five times the clarity.
Stegall, on the other hand, was the deep man. He caught half of his bass in waters shallower than five times the clarity, and three fourths were shallower than eight times it.
Conclusion? The odds of getting bit are good down to about eight times the water clarity.
Different Strokes
What accounts for the differences in the depths at which the anglers caught fish? It may be their style of fishing. And that may be driven partly by purpose, partly by habitat.
Horton fishes shallow when shallow cover is available. In Clarks Hill, where clarity was 10 feet and thick, shallow cover was lacking, he didn't hesitate to throw deep cranks. But bass were caught less than six feet deep on all his other trips.
In the events he fishes, Horton needs quality fish and puts it on the line for five good bites. Pitching a jig or tube to shallow cover is his mainstay on most lakes with fish-holding cover.
He fishes fast and tight. It doesn't take long to thoroughly fish cover pitching a jig or tube in two to four feet of water. A lipless crankbait and a soft jerkbait scored fish at these depths in the early spring, when the water was 52 degrees and water clarity 12 to 24 inches. Later in the year as the water temperature climbed into the 60s, a jig and tube produced fish.
Shaw is a spinnerbait wizard. The presentation is compatible with the low water clarity—usually less than 12 inches—typical of the Oklahoma waters he fishes. Like any good angler, he is always looking for quality fish. But in the tournaments he fishes, limits of keepers cash checks.
So his modus oper-andi is to catch a limit, then upgrade. With water temps in the 50s and water clarity at 12 inches, Shaw caught fish on jigs and spinnerbaits fished one to five feet deep. On one trip when water muddied and clarity was only two inches, he drew bites swimming a jig four feet down over 10 feet of water.
Another day, when water clarity was 20 inches, Shaw boated bass pulling a spinnerbait seven feet deep over 20 feet of water. As the water warmed into the 60s, 70s and 80s and water clarity was less than 15 inches, spinnerbaits and soft plastics fished one to three feet deep produced fish.
Although some of Stegall's trips were tournaments or prefishing, the vast majority were guide trips. His objective: minimize time between bites for his clients. It is also important that most of his guide trips were on Pickwick, a Tennessee River impoundment with little vegetation or shallow woody cover.
Years of experience have taught Stegall that ledges and underwater humps are the best places to find bunched-up bass, especially smallmouths, a situation that satisfies his clients and makes his work easier. When water temperatures were 48 to 60 degrees and water clarity 12 to 16 inches, he relied on jigs and plastics on ledges in eight to 12 feet of water and jerkbaits, cranks and lipless rattlebaits in the eight- to 10-foot zone.
As the water warmed, clarity increased, usually ranging from 24 to 30 inches. Prespawn fish were caught in three to 10 feet of water, primarily on rattlebaits fished at moderate speeds and plastics fished on bottom.
After the spawn and through summer, Stegall primarily fished soft plastics on the bottom in six to 10 feet of water. Like any top guide, he always adjusts his presentation to catch different groups of fish. On some trips, bottom-hugging cranks fished in eight to 12 feet deep water produced good catches.
What This Means For You
Fish-catching patterns are about probabilities and statistical relationships. But pinning them down defies science for several reasons.
First, there are too many uncontrolled variables. Habitat is at the top of the list. Fish aren't everywhere. Fishing the right depth doesn't matter if your lure is in the wrong habitat. When good shallow cover is available, fish it. It might be to your advantage to find lower clarity water to make the shallow cover work better. When the water clears, look for deeper cover.
Other confounding factors in this experiment included water temperature—which couldn't easily be factored out—and spawning. The study spanned the spawn, a time when bass move shallow regardless of the water clarity. But it's worth noting that among all three anglers, only seven trips coincided with peak spawning.
Admittedly, this study was also far from perfect because the anglers didn't fish a wide range of depths at each level of water clarity. I doubt they would have been excited about having to spend equal time fishing all depths from two to 30 feet each time out.
For example, Stegall's results indicate that Horton would have caught bass deeper if he would have spent more time fishing deeper. Similarly, Horton's data suggests Stegall might have caught more fish shallow, had he tried.
Despite the imperfect science, catch depth was related to water clarity. Building your own catch-depth-to clarity ratio for the waters you fish may put more bass in your boat.
At the very least, the pros' findings can help you eliminate spots when your favorite water goes murky.