Different Preferences: With the exception of spawning season, we typically think of smallmouth roaming deeper northern waters, often in 30 feet or more. Extreme clarity may make the fish feel less secure in shallower areas, while more water over their heads means a more relaxed fish. An efficient sight feeder, smallmouth want water clarity, but they also understand the importance of stealth.
Southern smallies generally contend with more off-colored water, so they don’t mind living shallow. These fish often show up on deep offshore ledges and other structure, but rocks and gravel bars in 10 feet or less find many of the fish taking advantage of the shallow light penetration.
As far as weather, northern fish are decidedly more tolerant to cold, while their southern counterparts react more decidedly to chilly weather. Both species instinctively gravitate to current for feeding. Still, southern fish that spend a lot of time in tailraces tend to move away from strong current in the wintertime to minimize their work and preserve maximum calories for warmth.
Another difference, northern smallmouth seem to be most active during sunny, calm days when they enjoy maximum visibility. Southern fish tend to side with the largemouth crowd and favor windier days with cloudy or overcast skies.