Water Types
The oligotrophic lake is cold, deep, and infertile. Although found elsewhere, it is the classic lake of the Canadian Shield. Here the smallmouth often occupies the top section of a two-storey fish community. Lake trout, whitefish, and smelt or ciscoes reside in the lower storey of cold water beneath the thermocline. Rocks, a retreat to deep water, and possibly a little submerged wood satisfy the need for protection or cover in this environment. This type of lake is usually characterized by a conspicuous absence of vegetation. When you do find some, it can be an important key to bass location.
On the other hand there is the mesotrophic lake, the ideal smallmouth environment in a lot of ways. These lakes of medium fertility, temperature, and depth offer a variety of habitat suitable for smallmouths. They usually have more vegetation than oligotrophic lakes and as a result produce more smallmouths.
However, warm, nutrient-rich shallow lakes should not be over-looked by the angler in search of bronzebacks. Not all eutrophic lakes have populations of smallmouths because turbidity, high temperatures, poor oxygen levels, or lack of suitable spawning sites prevent the establishment of the species. But when these factors are within the range of tolerance, the smallie fishing can be fantastic!
The smallmouth bass is totally at home as a river fish. Rivers through-out its range are usually underfished. That means there are more lean, catchable fish for the angler who knows where to find them in a river. Smallies in rivers spend their lives fighting current which gives them a well-muscled body and an aggressive nature, making it a pleasure to do battle with the river bass. These fish are also less susceptible than lake fish to those occasional spells of "lock-jaw" brought on by sudden changes in barometric pressure and water temperature.
Geologically young headwater streams characterized by steep banks, a steep gradient, and very cold and infertile water seldom hold smallmouth. As the river descends and begins to age a little the chances of smallies calling it home increase. As we move downstream and the river slows and warms we may continue to find bronzebacks. Populations sometimes do well in nutrient-rich, mature river sections since the water is moving enough, although slowly, to prevent turbidity and temperature problems.
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