Ask a seasoned angler to define good bass habitat and you’re likely to hear about laydowns, weededges, creek channels, stumpfields, mats, red clay banks, chunk rock, shell bars—the list goes on. No doubt all are places frequented by adult bass, and all are good bass habitat. But good bass habitat means not only homes for adult bass, but also spawning sites and nursery areas where young fish find shelter from predators while transitioning rapidly from prey to predator.

Consistently strong bass populations have successful spawning, good survival, and moderate to fast growth for that region. These characteristics are all affected by habitat. Biologists have studied the habitat requirements of largemouth and smallmouth bass and have learned some management tricks to maintain or improve it.

Spawning Habitat

Bass spawn on firm substrate. Largemouth are fairly flexible—any hard substrate, generally in 2 to 6 feet of water, suffices. Largemouth bass are industrious, too, even ingenious. They may fan away silt or decayed plant material, uproot plants, or nest on logs, stumps, or roots, if the bottom has too much silt or detritus. Smallmouths are more finicky; for them, spawning is much more successful on gravel or cobble. Protection from wind and waves often is critical, as well.

In waters with fluctuating levels, elevation around spawning time can be important. Biologists often work with reservoir managers to avoid drawdowns or drastic fluctuations when the water is between 60°F and 75°F.

Cover is desirable but not essential. Nests are usually built next to stumps or rocks or under logs if this cover is available. Where spawning is sporadic due to limited cover, adding objects aids reproduction. Clearing silt off gravel banks can increase smallmouth spawning success. Half logs or spawning benches—planks raised about 8 inches off the bottom—have been found to benefit spawning by both species. Location of these structures is important: They need to be on firm substrate for largemouth, on gravel or cobble for smallmouth, and they should be deep enough so they won’t be left high and dry if the water level drops. Savvy managers place spawning structures at various depths to hedge their bets.

Nursery Areas

Young bass are the preferred forage of many predators including larger bass, so they naturally seek shelter like brush, dense vegetation, or rock. But their best defense against would-be predators is growth. The faster they grow, the fewer fish that can catch and consume them. And the bigger they are by late fall, the more energy they have to survive their first winter. The ideal nursery location offers cover and prey for small bass.

Bass up to 2 or 3 inches long often feed on aquatic invertebrates such as insect larvae. The abundance of invertebrates is related to the amount of surface area they can live on—a flat lake bottom provides substrate, but a brushpile offers considerably more living area. Beds of aquatic plants, even those with simple forms like eelgrass, provide even more substrate. It’s been estimated that a 5 percent area coverage of mixed aquatic plants in a 100-acre lake provides about the same amount of substrate habitat for invertebrates as do 11,000 Christmas trees.

Aquatic vegetation yields abundant cover and food, but it’s possible to have too much of a good thing. Expansive areas of dense vegetation are conducive to high survival of largemouth bass fry and fingerlings, but young bass grow slowly after reaching a couple of inches. They find a good supply of invertebrate food in the grass, but by the time they reach 2 to 3 inches, they need fish in their diet for rapid growth.

Richer supplies of small fish like shad fry are found scattered around, rather than inside dense vegetation, or are in open water. High survival of bass fingerlings in dense vegetation also can result in slow growth, since forage supplies may be insufficient to feed the abundant bass.

Vegetation typically boosts bass recruitment, but how much vegetation is enough? The number hasn’t been pinned down, but studies indicate that lakes with 25 to 40 percent coverage by aquatic macrophytes usually have good largemouth recruitment.

Smallmouth are a different story. Shallow gravel and rubble seem important for good growth and survival of young.

The Adolescent Years

Bass that survive their first year by dodging predators and surviving an energy-sapping winter must continue to feed and grow. Yearling fish may range from 3 inches in the North to 5 to 10 inches or more in the South. Their food, mostly crayfish and fish, must be the right size—small bass can’t eat large prey. Conversely, bass can burn more energy chasing, catching, and consuming very small prey than they gain from eating it.

We explored the bass “foraging window” in the 2005 Bass Guide. Briefly, a largemouth readily consumes fish up to about one-third of its length; a smallmouth can easily ingest forage up to one-fourth its own length. So, abundant forage fish from 1 to 3 inches long provide good growth opportunities for most yearling bass.

Many varieties of small fish can fill the bellies of yearling bass. But consider that forage fish are growing, too. Shad are the primary prey in many waters outside the Far North. Typically, gizzard shad reach 4 to 6 inches in their first year. Where that’s the case, young shad only serve as bass food for part of the yearlings’ growing season. For good growth, yearling bass need a range of sizes of forage, and that means diverse forage species. Effective habitat management for intermediate-sized bass involves habitat manipulations that yield an array of prey species native to the waterway.

Aquatic vegetation generally benefits juvenile bass by providing prey. Dense vegetation often houses small minnows, topminnows, crayfish, and sunfish, but if the bass can’t find or catch them, they don’t grow much. Intermediate coverage of clumps of vegetation is better than vast areas of matted weeds.

Big Bass

Fast growth and high survival yield abundant big bass. Can optimal habitat build big bass? Certainly, but maybe not in the way many anglers think. Big bass come from little bass. Like smaller ones, they need food—lots of the right size of easily catchable prey. So, habitat for big bass really means habitat for their prey. The foraging-window principal still pertains, except that larger bass can eat larger prey, so their foraging window is much broader. More cover can mean more forage. For adolescent bass, however, too much cover can mean a lot of forage but poor bass growth, if they can’t catch their food.

Fishery managers often add bass-attracting structures (fish attractors) when cover is scarce. Although often effective, this is an expensive and time-consuming activity, and it requires a lot of fish attractors. Brushpiles and wooden structures don’t last long; rockpiles and artificial reefs are better, especially for smallmouth bass. Rockpiles last but building them takes special equipment, unless the rock can be dumped from trucks during a reservoir drawdown or placed during winter ice cover.

Aquatic vegetation is a low-cost, natural fish attractor. But not all lakes or reservoirs foster aquatic vegetation. Biologists are now learning effective methods for establishing native vegetation to benefit both fish and anglers, and to reduce invasions by non-native plants.

Habitat Management

The best bass populations have stable reproduction, fast growth, high survival, and a high bass biomass (weight of bass per acre), relative to the productivity of the lake or reservoir. Habitat affects all these factors, so careful habitat management is the smartest way both biologically and economically to maximize bass populations. Under high fishing pressure, harvest must also be limited either by voluntary selective harvest or by regulations. Conversely, where fishing or harvest pressure is low, such as in private ponds, removing bass increases growth rates and improves population structure. But good habitat management provides the best basis for large, stable, and fast-growing bass populations. n

*Dr. Hal Schramm leads the Mississippi Cooperative Fish and Wildlife Research Unit at Mississippi State University in Starkville. He’s an avid bass angler and frequent contributor to In-Fisherman publications.