Anglers know that walleyes have unique eyes allowing them to see particularly well in lowlight, and it is no secret this same eyesight causes walleyes to be adverse to bright light conditions. This scenario creates a well-proven pattern of walleyes holding deeper in brighter light conditions, and shallower as light decreases. This light intensity/location scenario is generally an ironclad rule for lake fishing, except early in the season when walleye seem to buck this trend and hang shallower near spawning grounds. As much as light levels effect walleye location, there is a greater factor to consider for identifying walleye fishing locations, especially river walleye.
Before I get to far, I want to quickly point out the well know fact that wind drives walleye shallow, just like the effect of a setting sun does. The more wind, the higher the waves, and the higher the waves, the less light penetration into the water, then ol’marble eye comes shallower. In essence it is light diffraction that positions how deep walleye hold in lakes or rivers.
As mentioned wave action cuts light penetration, but “dirty” water, water either carrying a heavy sediment load, water high in suspended and dissolved particles, or water high in tannins, is the greatest influence in stopping light penetration into water. Each lake or river has differing water characteristics of suspended and dissolved particles and may have tannins as well. With the exception of algae blooms, the level of these suspended and dissolved particles and tannins in lakes, or its overall water clarity, is usually static or at any point in time similar from day to day. Naturally rivers water clarity varies and differs over time thanks to their tributaries. When the snow pack melts, and April showers come, the creeks, streams, and small rivers contribute suspended sediment into the big river.
River fishermen know water clarity is not static, they are aware it changes on a regular basis, from new inputs. This spring on the Mississippi the water is very clear and because our cold March created little melt, the water actually is not much darker than it was in middle of winter. Last year during this same time, the water was far dirty and higher.
Trophy walleye hunters know to tangle with a true hog, your best bet is to fish shallow, but shallow does not work when the water is clear. To gauge fish holding depths you need to have a handle on the how dark the water clarity is. In dirty water, walleyes can and will hold in as little as two feet of water, and easily found in less than six feet. When I speak of fish in two feet of water, I am referring to daytime fishing. Currently where I fish on the Mississippi, you will not catch fish in the day in those same ultra shallow depths in bright light.
Rivers flow in interesting ways, often new inputs into a larger river are dirtier than the main river. These inputs are usually smaller streams than the main river, and where they enter they create an eddy. These eddies circle into themselves and keep their dirtier water, and within these eddies the water clarity is darker than the main river. Here fish can be found shallower than the main river. However this darker water in the eddy maybe too dark, and worse fishing overall, reading water clarity and picking the best walleye holding depths for the time of day does take time.
Water clarity in rivers is not a situation where the dirtier the better, it is a situation where you want some, but not too much. It is like water flow, you want some, but too strong and the eyes will not hold there. Though for good daytime shallow water fishing you need to have some color in the water. Often in spring huge water rises make fishing very difficult, as the water is just too dirty, and fish have a difficult time picking up your bait. I have found the best fishing happens after the river crests and the ultra dirty water clears and catches improve.
Clarity not only affects fish holding depths but also determines the best times of day to target big fish. Remember big fish in the shallows are feeding, so if the clarity is clear they will not move shallow until low light conditions. When the water is very dark the night bite is poor. Counter intuitive to fish holding in bright sunlight, some of the best dirty water fishing takes place in the shallows during bright sunshine, no winds, no clouds. I have come to believe the more light actually helps fish locate prey better in this dark water.
Briefly, strong current, or moving waters will also reduce light penetration and drive fish shallow, but dirtier water and higher flows from river level rises are strongly correlated and difficult to separate. Normally if you have one you have the other. Undoubtedly walleye location based on water flow is an extremely important topic, but touched on in another time.
Water clarity, either in lake fishing or river fishing strongly drive walleye depth choices, get in touch with where your river water clarity is at, develop an overall feel for this clarity to greatly aid your depth choices and time of day to target and tangle with some of the biggest walleyes swimming.
Keep Catchin’