Fall Feeding Frenzy: Bass and Walleye Patterns | Bassfinity Blog<br>Back

The water cools, the bait moves, and the bass go on a feeding frenzy to fatten up for winter. It is the most repeated sentence in fall fishing, and the fishing really is good. But the explanation is doing something the data does not support, and the gap between them is why so many good anglers fish November like it is October.

Fall is the best stretch of the year on most water. Bass and walleye both get more catchable, more predictable, and more willing to chase something moving. None of that is in dispute.

What is worth questioning is the mechanism everyone attaches to it. If you believe fish are eating more as the water cools, you will keep fishing fast when you should have slowed down, keep chasing the backs of creeks after the bait has already pulled out, and treat a slow December afternoon as a failure rather than as exactly what the season predicts.

So here is the fall story with the mechanism corrected, for both species, and where to go next on each.

Fall is a temperature, not a month

The single most useful habit in autumn is carrying a thermometer and using it in more than one place. A large reservoir is not one water body thermally - a shallow tributary arm, the main basin, and the dam end can differ by several degrees and sit in genuinely different phases of the season on the same afternoon.

Everything below is keyed to water temperature rather than to a date, because a lake at 68 degrees in Alabama and a lake at 68 degrees in Minnesota are fishing far more alike than two lakes on the same calendar week.

What turnover actually does - and what it does not

Fresh water is densest at about 4 degrees Celsius, roughly 39 Fahrenheit, rather than at freezing. Through summer that fact stacks a lake into layers: a warm, light, oxygenated upper layer, a cold and dense lower one, and a thermocline between them that blocks mixing. Over months, decomposition on the bottom burns through the oxygen trapped below, and nothing replaces it.

In autumn the surface cools, gets denser, and sinks. Eventually the density difference is small enough for wind to mix the whole column top to bottom. That is turnover. It re-oxygenates the depths, and on the way up it drags oxygen-poor water and suspended organic material through the lake - which is why a turning lake looks murky, sometimes smells faintly of sulfur, and fishes badly for a stretch.

Now the part usually left out. Turnover is not one event that happens to every water on a schedule:

Shallow water may never stratify at all. A creek arm or flat under roughly six feet generally mixes all summer on wind alone. No layers means no turnover to recover from - which makes these the places to be while the main lake is unsettled.

Severity scales with how bad the bottom layer got. A deep, clear, low-nutrient lake mixes cleanly. A shallow, fertile reservoir with a summer-long anoxic bottom is the one that turns the color of coffee.

It is not instantaneous. Virginia's Department of Wildlife Resources puts the disruption at roughly one to two weeks, and recommends fishing the shallow creeks that are unaffected while it passes.

Arms turn on their own schedule. Days or weeks apart within one reservoir.

The practical read: do not write off a lake because somebody said it was turning over. Look at the water in front of you.

The frenzy is real. The reason usually given for it is not.

Here is the part that gets skipped. A fish's capacity to eat and grow does not increase as water cools. It peaks well above where autumn ends up, and falls off from there.

The Great Lakes Fishery Commission's temperature compilation (Wismer and Christie, Great Lakes Fish. Comm. Spec. Pub. 87-3, 1987) lists optimum growth temperature for subadult largemouth bass at 26 to 28 degrees Celsius , about 77 to 82 Fahrenheit , with the lower bound for growth near 10 Celsius, about 50 Fahrenheit . For walleye, the same compilation records a final thermal preferendum of 20.6 to 23.2 Celsius - roughly 69 to 74 Fahrenheit - and a growth optimum near 22 Celsius, about 72 Fahrenheit , the latter drawn from Hokanson's percid review in the Journal of the Fisheries Research Board of Canada (34:1524-1550, 1977).

Read those against a fall thermometer. A lake at 78 degrees in September is at or near a bass's optimum. At 68 in October it is below it. At 52 in late November a bass is near the temperature where growth stops entirely. Daily consumption is declining across the whole back half of autumn. Bioenergetics modeling makes the same point from the other direction - Rice, Breck, Bartell and Kitchell built their largemouth growth model (Environmental Biology of Fishes 9:263-275, 1983) with temperature as a ceiling on consumption, not a throttle you open by cooling the water.

So why does the fishing get better? Because catching fish and fish eating are different problems. Four things change, and none of them require a fish to eat more...