The Bass Professor: Why Behavior Comes First

Doug Hannon grew up fishing in Florida in the early 1970s, a period when the Sunshine State was the undisputed capital of big largemouth bass. He arrived with a trust fund, a psychology degree, and a consuming obsession. He began by interviewing the reclusive old-timers who knew the big-fish haunts of Florida's backcountry lakes. Then he went to work developing his own understanding — not from books, but from direct observation.

He built a large research tank in his backyard to study bass behavior under controlled conditions. He became an accomplished scuba diver and underwater photographer, spending thousands of hours below the surface watching how bass reacted to lures, to light, to temperature changes, to other fish. He worked alongside cameraman Glen Lau, (Photo-Glen Lau and his dog) who documented underwater footage that was revolutionary for its time. Together they produced a series of  instructional videos for 3M — Understanding Bass, Catching Big Bass, and Bass-Formula for Success — that introduced a generation of anglers to the idea that fishing success begins with understanding, not tackle selection.

By the mid-1980s, Hannon had caught and released more than 500 bass over ten pounds. By the end of his career, that number exceeded 800, including a personal best of seventeen pounds. Journalist Frank Sargeant of the Tampa Tribune dubbed him "the Bass Professor," and the name stuck. He appeared on the cover of Bassmaster magazine twice in a single year. He held nearly twenty patents for fishing-related innovations. Outdoor Life named him one of twenty-five people whose lifetime achievement had the greatest positive influence on hunting and fishing.

That philosophy is the lens through which everything in this article should be read. Hannon's greatest contribution was not a lure or a rod guide system. It was the insistence that the angler who understands the biology beneath the water will always outperform the one who simply follows the gear market. Forty years of science has only reinforced that conviction.

Winter: The Cold Deep and the Waiting

A largemouth bass is not a mammal. It generates no body heat of its own. Every biological function it performs — digestion, movement, reproduction, even the speed at which it processes information — is governed by the temperature of the water around it. This single fact explains more about bass behavior than any other piece of knowledge an angler can possess.

In winter, water temperature dictates a simple imperative: find stability. Cold surface water sinks. In most lakes and reservoirs, the deepest water becomes the warmest and most stable zone during winter months. Bass congregate there — near the bottom of main lake creek channels, along steep bluff walls, on deep points where abrupt contour changes allow them to slide up or down as conditions shift. They are not randomly scattered. They are stacked in the places where temperature variance is lowest.

Their metabolism slows dramatically. Scientific research confirms that food intake becomes negligible below fifty degrees Fahrenheit and approaches zero below forty. A bass in thirty-eight-degree water is not hunting. It is existing. Its heart rate drops. Its enzymatic processes slow. It expends the absolute minimum energy required to maintain position.

What Hannon observed in his tank — that bass in cold water become almost statue-like, holding in one place for extended periods — was later confirmed by telemetry research using acoustic tags implanted in wild fish. Modern tracking studies show that winter home ranges shrink to a fraction of warm-weather size. Some individual bass barely move more than a few dozen yards for weeks at a time. Yet the same research offers a nuance: even in near-freezing water under ice cover, bass engage in slow, low-energy movement. They do not fully stop. They are waiting, not sleeping.

Dissolved oxygen plays a secondary but important role in winter. In lakes that freeze over, oxygen exchange with the atmosphere stops. If ice cover persists and aquatic vegetation dies off, dissolved oxygen levels can drop to dangerous thresholds. Research has established that bass begin to show behavioral stress responses — yawning, unusual vertical movements, seeking open water — when dissolved oxygen falls below 2.0 mg/L. They will relocate to find breathable water even in the coldest conditions.

The Awakening: Pre-Spawn

Something shifts in late winter that has nothing to do with the calendar. Days lengthen. The angle of sunlight changes. And somewhere in the deep water where a largemouth bass has been barely moving for weeks, a biological clock begins to turn.

The trigger is not air temperature. It is not the date. It is the combination of increasing photoperiod — longer days, more light penetration — and rising water temperature. These two signals, working together, activate hormonal responses that have been hardwired into the largemouth bass for millions of years. The urge to reproduce begins to override everything else.

Pre-spawn officially begins as water temperatures climb into the 45°F to 55°F range. The fish start moving. Not quickly, and not in a straight line to the shallows — but moving. They follow established routes along underwater structure: creek channels, submerged road beds, points that transition from deep to shallow, ledges that serve as natural highways between wintering areas and eventual spawning flats. Modern sonar and GPS mapping have made these migration corridors visible for the first time.

The bass don't arrive at spawning areas all at once. They stage. They move to a secondary point or a channel edge near the spawning flat, hold there for days or even weeks, and feed. Then they move shallower. Then they stage again. This progressive, multi-step migration means that during pre-spawn, bass can be found across a wide range of depths on the same body of water at the same time.

Females drive the pre-spawn feeding urgency. They are packing on weight, building egg mass. A female preparing to spawn needs calorie-dense food, and shad are the primary target. It is not a coincidence that shad begin spawning roughly a month before bass do — bass are keyed to this activity as a food source. When shad go shallow, bass go shallow behind them, fueling themselves for the spawn ahead.

The pre-spawn period produces some of the biggest bass catches of the year. Females at this stage are at maximum body weight, full of eggs, feeding aggressively. They are not yet locked onto beds and are covering water. The fish that Hannon spent his career studying — the ten-, twelve-, fifteen-pound Florida giants — were most vulnerable to capture during this window.

Reading the Staging Zones

Understanding where pre-spawn bass stage is the difference between a spectacular day and a fishless one. The fish are not randomly distributed — they are moving along specific structural highways, pausing at specific waypoints. Electronics now make these locations findable, but knowing what to look for matters more than the technology itself.

The Spawn: Nests, Guards, and the Science of Reproduction

When water temperatures reach the mid-fifties and begin pushing toward sixty degrees, the pre-spawn transitions into the spawn itself. It is one of the most behaviorally complex and biologically demanding periods in the largemouth bass's year — and one of the most extensively studied.

The male arrives at the spawning flat first. He is selecting real estate. His criteria are specific: hard bottom material — gravel, sand, clay, shell — in water between one and six feet deep. He wants proximity to cover: a nearby dock piling, a fallen tree, the edge of a weedbed, a submerged rock. He wants protection from direct wind and wave action. Research tracking hundreds of nests across multiple lake systems has shown that male bass demonstrate consistent habitat preferences that persist year after year, and that individual males frequently return to the same general area — sometimes the same precise location — in successive spawning seasons.

The Spawning Sequence

Modern research by Philipp, Cooke, and others has documented that tournament-style handling — livewell confinement, transport, and release distant from the nest — significantly increases nest abandonment rates and brood mortality. Studies show nest predators move in within minutes of a male's absence, and egg survival rates drop sharply. Hannon was among the earliest voices arguing for the catch-and-release ethic broadly. The research he couldn't have conducted at the time has since validated the concern with hard data.

The spawn does not happen all at once across a fishery. Bass spawn in waves, triggered in part by the full moons of spring — which appear to serve as a synchronization signal for groups of fish — and by localized water temperature conditions. The overall spawning window across a body of water can stretch six to eight weeks.

Post-Spawn: Recovery and the Summer Dispersal

The spawn extracts a toll. Females have expelled enormous physical reserves building and carrying egg mass. Males have gone days without feeding while burning energy guarding nests. When it is over, both sexes enter a period of recovery that manifests as one of the most frustrating stretches of the fishing calendar.

The post-spawn lull is real. Fish that were catchable on a nest yesterday are now sulking in adjacent cover, physically spent and behaviorally shut down. They are not feeding aggressively. They are not moving purposefully. They are recovering. This period typically lasts one to two weeks on any given section of a lake — though the staggered nature of the spawn means some fish are always further along in the cycle than others.

What pulls them out of the lull is food. And the timing is not accidental. Bluegill begin their spawning activity almost immediately after the bass spawn concludes. Shad that were spawning in the pre-spawn period have now produced juvenile shad — newly available forage in massive quantities. The calendar of the entire forage community has been synchronized with the bass spawn, positioning maximum food availability at exactly the moment bass need to feed most urgently.

As water temperatures push through the seventies, bass begin their transition to summer patterns. What telemetry research has revealed is that this transition follows specific, repeatable pathways. Bass don't scatter randomly. They follow structural corridors — the same creek channels, points, and ledge systems they used during the pre-spawn migration — now moving in the other direction, pushing gradually deeper as surface temperatures climb.

Two distinct populations emerge as summer establishes itself. One group remains shallow, associated with available cover — dock systems, vegetation, laydowns, rip-rap — functioning as ambush predators in the traditional sense. The other group moves offshore, suspending over humps and ridges and the intersections of creek channels in fifteen to thirty feet of water, following the movements of shad schools. Both populations are catchable. Neither is random. Each is responding to the same underlying drivers: temperature, oxygen, and food.

Summer: The Thermocline, Oxygen, and the Compressed World

Summer is when the physics of freshwater lakes assert themselves most forcefully over bass behavior. Understanding what happens to a lake in summer is, in many ways, the most important scientific concept an angler can grasp — because it explains not just where bass are, but why, with a precision that no amount of lure selection can substitute for.

As surface water heats through the summer, a phenomenon called thermal stratification develops. Warm, lighter water sits on top. Cold, denser water settles to the bottom. The boundary layer between them — the thermocline — becomes a wall that mixing cannot penetrate. Below the thermocline, photosynthesis stops because light cannot reach it. Oxygen-producing plants and algae are absent. Bacterial decomposition of organic material on the lake bottom consumes what dissolved oxygen remains. The result is a zone of hypoxia — water that is too oxygen-depleted for bass to inhabit comfortably or survive in for extended periods.

Research has confirmed that bass select for dissolved oxygen concentrations above five milligrams per liter under normal conditions and will avoid areas where oxygen falls below two milligrams per liter. Above the thermocline, oxygen is adequate. Below it, in most stratified lakes during the heart of summer, it is not. This creates a squeeze. Bass are compressed into the oxygenated layer of the water column — forced upward by the dead zone below, pushed down by the thermal stress of the surface layer above. In a stratified mid-summer lake, bass may be holding in a band of water only a few feet thick.

Hannon understood instinctively that bass in summer were doing something beyond simply seeking cooler water. His tank observations showed that bass in warmer water became lethargic not just from temperature but from the metabolic cost of digestion in a low-oxygen environment. Science has since confirmed the mechanism: at elevated temperatures, the oxygen demand of digesting a meal competes directly with the oxygen demand of basic body function. When that equation becomes unfavorable, bass stop eating. They are not lazy in summer. They are managing oxygen budgets.

Peak summer feeding does not happen at midday when surface temperatures are highest. It happens in the early morning hours before solar heating peaks, in the evening when surface temperatures have stabilized, and on days when wind or cloud cover disrupts stratification and introduces oxygen to the water column.

The practical implication extends to structure selection as well. Research comparing lakes with abundant woody structure to those without found that bass in high-structure environments have smaller home ranges, spend less time in open water, and show higher feeding rates through ambush predation. The sit-and-wait predator Hannon described — a bass that positions itself in cover and waits for prey to come within range rather than pursuing it through open water — is precisely what the telemetry data confirms. Find the structure within the oxygenated band of water, and you have found the fish.

Fall: The Feeding Imperative

Fall is the season that rewards the angler who is still paying attention. The crowds have thinned. The summer tournaments are over. Most recreational anglers have put their boats away. And the bass are preparing for winter with an urgency that makes them as catchable as they will be all year.

The trigger is the same one that started everything in the spring — water temperature — but moving in the opposite direction. As surface temps drop below seventy degrees, bass metabolism resets. The heat-driven suppression of appetite lifts. Bass begin feeding with purpose, and they need to. Winter is coming. The fish that enters winter with the greatest energy reserves will survive it best and emerge into spring in the strongest condition.

At the same time, the shad undergo their own fall migration. As cooling water washes nutrients and runoff from the surrounding watershed into the backs of creek arms and coves, plankton blooms occur. Shad follow the plankton. Bass follow the shad. In the fall, the backs of creek arms and secondary coves become some of the most productive water on any lake, as the entire food chain stacks into these areas in a predictable progression.

Fall also brings turnover — the breakdown of summer stratification. As surface water cools, it becomes denser and sinks, mixing with the water below. The thermocline dissolves. For a brief period the lake is in transition: oxygen levels equalize, temperatures equalize, and bass distribution becomes temporarily scattered and unpredictable. Turnover can last several days to a couple of weeks. Fishing through turnover is notoriously difficult.

After turnover stabilizes, the lake takes on a new character. Oxygen is now available at all depths. The constraints of stratification are gone. Bass can go where the food is without restriction. Dying vegetation is a key indicator — dead and dying weeds consume oxygen rather than produce it, and bass abandon those areas progressively, following the green living edge as it recedes toward deeper water. Track the green vegetation and you track the fish.

By the time water temperatures drop into the upper fifties and low sixties, bass have returned to many of the same areas they occupied during the pre-spawn — the staging zones, the transition edges, the main lake points near depth. The fall fisherman who understands this symmetry — that pre-spawn locations and late-fall locations are often nearly identical — has a significant advantage. The cycle is closing. The fish are heading home.

What Hannon Got Right: The Science That Caught Up

The forty years since Hannon was doing his most influential work have produced a body of peer-reviewed science on largemouth bass that would fill a library. Several findings are especially relevant to the practical angler, and each one connects directly back to something Hannon observed from a jon boat and a dive mask long before the instruments existed to prove it.

Color Vision

Bass possess dichromatic vision, meaning they have two types of color-sensitive cone cells compared to the three that humans have. Their peak sensitivities are in the red-green spectrum. Red wavelengths are absorbed by water relatively quickly — in stained or deep water, a red lure loses its color at surprisingly shallow depths and appears dark. Blue and chartreuse register well at depth. In clear water and bright conditions, color matters more. In low light or stained water, contrast and profile often matter more than specific hue. Hannon wrote about lure color in the context of water clarity and light conditions decades before the scientific literature confirmed the specifics. His instincts were sound.

Moon Phase — A Nuanced Picture

Hannon published moon time guides and advocated for solunar influences on bass activity. The science on this is nuanced. Telemetry research confirms that lunar phase does influence depth distribution during spring and summer — bass tend toward greater depths during specific phases of the waxing moon. However, research by Professor Mike Allen using trophy catch data showed that lunar phase has limited predictive value for daily feeding windows in freshwater bass. The full moons of spring matter as a spawning trigger and migration signal. Day-to-day feeding activity is more reliably predicted by weather systems, temperature stability, and time of day than by the moon calendar. Hannon was right that the moon matters. He may have overstated how much it matters once spawning season has passed.

Catch-and-Release and the Value of Old Fish

This may be Hannon's most enduring legacy in terms of scientific validation. He was among the earliest advocates for releasing big bass rather than mounting them, arguing that the genetic value of a large, old fish to the population was greater than its value on a wall. Subsequent research has confirmed that large, old female bass are disproportionately important to recruitment — they produce more eggs, larger eggs, and fry with higher survival rates than younger females. The conservation movement Hannon championed from a philosophical position now has a firm scientific foundation.

Doug Hannon fished from a beat-up sixteen-foot aluminum boat with a forty-horsepower motor. He carried a handful of basic lures. He had no side-scan sonar, no GPS mapping, no dissolved oxygen meter, no acoustic telemetry. What he had was an understanding of why a bass does what it does — and that understanding, built through observation and curiosity and thousands of hours of direct engagement with the fish, produced results that modern science has spent four decades catching up to.

The lesson is not that electronics don't matter. They do. They have made visible things that Hannon could only infer. The lesson is that the angler who understands the biology beneath the graph, the behavior behind the blip on the screen, will always extract more from those tools than the one who simply follows the machine.

A largemouth bass lives a purposeful, predictable life. Every move it makes — from the deep cold of February to the staging flats of April to the compressed summer thermocline to the aggressive feeding of October — is driven by the same variables: temperature, oxygen, food, light, and the relentless imperative to reproduce. Master those variables, and you have mastered the fish.

The Bass Professor understood that. Now you do too.