The interactions of the three primary black bass species are determined by the individual characteristics of each species. All black bass are similar. All are basically very flexible in habitat requirements. Given multiple habitats with no or little competition for food or space, each black bass species will expand and occupy all of the available habitats that will work. Some places will be more suitable than others, but the bass population will expand, unless curbed by angling pressure, until all usable habitats hold as many of that bass species as the habitat will support.
Each species has habitats that favor its basic make-up, and each can survive and use habitats that are less suitable for it while more suitable to another. In competition with one another, each bass species tends to be found mainly in the habitat that best fits its particular nature, and to be less common in areas better suited to the capabilities and nature of another black bass species. But, there can be considerable overlap.
These separations are not always predictable, as multiple habitat features come into play and one feature like murky water may imbalance another like vegetation or soft-bottom for spawning. Moreover, the size of individual bass effects their ability to compete with other bass of the same and different species. A very large spotted bass may, for example, out-compete smaller largemouths and occupy the habitat containing the most food, regardless of the needs of smaller bass of the same or different species.
All black bass species apparently arose from a basic riverine stock, the spotted bass line. All black basses have very similar temperature minimums, maximums, and preferences. And aside from musculature and mouth shape/size, basic capabilities are similar. They all eat the same prey, providing they will fit into their mouths.
Spotted bass , and the species close to the Spotted Bass genetic line (see my article”Identification of Black Basses”) have physical and inherent behavioral characteristics developed in response to river habitats. Most of the fresh waters in the warmer part of the United States, save for portions of Florida, the marshy parts of the Mississippi delta, a few large river back-waters offered only riverine habitats. Body shapes, musculature, size, and growth rates of Spotted Bass are adapted to living in food-limited riverine habitats.
Spotted Bass and close relatives like current and clear water, do well rocky cover, but do well, perhaps equally well, in murky water. They are adapted to spawn and survive during low water conditions and droughts. They tend to be slow growing and relatively short-lived and small, and usually require small prey befitting their comparatively smaller mouths. Their feeding behaviors are based on the tactics that work in current and around rocks. They bite and grab prey frequently rather than just suck-in prey.
Smallmouth bass are an offshoot riverine species, but evolved closer to glaciers and have lifestyles better adapted to colder water. They also have lived and evolved in natural lakes for centuries . They are similar to spots in many capabilities and behaviors, but are less well adapted to murky conditions as they are almost totally visual feeders. When water is murky, spots have an edge over Small Mouth Bass, but Small Mouth Bass seem better adapted when waters fail to warm into the high 70s and remain in the lower portion of the black bass tolerance range.
Like Spotted Bass, Small Mouth Bass have feeding habits that emphasize visual feeding, bite more often than suck-in prey, and are prone to move up and down to attack preyfish from below, tactics most suitable for feeding in strong currents.
Largemouth bass are the black-sheep of the black bass family. They specialized and evolved to feed and grow in the backwaters, marshes, and slack-water areas of rivers. Their musculature is adapted to no-current or low-current situations. They are not adapted to fight current continuously, and have less stamina as a result. However, feeding in slack-water allowed Large Mouth Bass to develop features better adapted to feeding there. They have large mouths better suited to either suck prey out of vegetation and rocky cover or to over-run fleeing preyfish. They are masters of the short dash, but are likely to chase preyfish at the surface longer than the more riverine black basses.
How does all this effect anglers and the various bass they want in rivers and lakes they fish? Obviously, riverine black bass species generally do better than Large Mouth Bass in rivers The determination of whether Spotted Bass of Small Mouth Bass dominate in particular rivers tends to be associated with water clarity, which seems necessary for strong Small Mouth Bass populations but not necessary for Spotted Bass, and yearly temperature minimums and maximums. The farther north you go, except for cold waters released from some southern reservoirs, the more the habitat seems to favor Small Mouth Basss over Spotted Bass.
The situation becomes more complex in reservoirs. Some reservoirs are riverine in nature, with high flow-throughs. Large Mouth Bass seldom prosper in such waters and they naturally become the domains of either Spotted Bass or Small Mouth Bass. When reservoirs contain both a riverine upper section and slow moving section near the dam with minimal current and/or many long arms with intermittent stream inputs, they often support all three species. A multiplicity of factors like prey type, the depth range of the prey, type of cover, nature of the current, and just about every other habitat feature such as the dominance of vegetation or woody cover determines which bass species is/are favored and which is/are minimalized.
Species dominance changes with time as reservoirs age and habitat modifies. It is not uncommon for Small Mouth Bass and/or Large Mouth Bass populations to boom when reservoirs are new and full of nutrients. Spotted bass, better adapted to more limited diets and smaller prey, may become more plentiful as habitat for largemouths rots away. But, if a reservoir develops large amounts of vegetation in its old stages, largemouth may resurge and become the dominant bass.
Habitat is always setting the parameters and telling you what it will support. Whenever Small Mouth Bass or Large Mouth Bass are replaced by Spotted Bass it’s most likely because the Spotted Bass better fit the available habitat. Trying to kill-off the spots will make a bit more food available, but it will go to the other spots, not to any species less able to compete with the spots. If habitat is obviously well suited to the larger black bass species, they will thrive and be found in their own optimum areas. Large Mouth Bass will be in the coves and grass, the Small Mouth Bass will be in the clear current below the dam inflow and rocks near current, and the Spotted Bass will take what is left as both Large Mouth Bass and Small Mouth Bass can out-compete them in habitats that favor the two larger species. Spots take the leavings, but will be dominant in lakes, rivers, and reservoirs less suited to the larger species.