Water temperature: Minimal temperature over extended time
Fish mood: Inactive
Even in Florida, there’s a winter period—it’s whenever the water turns its coldest. In southern states, water temperature ranges between 40°F and 55°F. In northern states where lakes freeze, water temperature ranges from about 32°F immediately below the ice, to 39°F near bottom.
Not surprisingly, bass at this time of year move to the deepest water they inhabit all year, because it’s also the warmest. Just how deep, depends on the body of water.
In natural lakes, deep flats or basins of moderate depth, 15 to 30 feet deep, are common. In shallow, eutrophic lakes after vegetation dies back, oxygen levels fall, affecting all animal organisms. In some lakes, oxygen deprivation in deep water forces bass to move shallower. In the far North, winterkill occurs when water freezes deeply and oxygen becomes depleted. The largest fish, with their greater demand for oxygen, die first.
In deep reservoirs, bass may aggregate down to 50 feet or more, where they suspend in timber near deep creek channels. Even though they’re inactive, aggregations are so large that a few fish may strike a lure. Largemouth bass that are holding in water deeper than 30 feet may not survive the gas expansion in their air bladder, eyes, and other organs, which comes from being hauled out of deep water into our vastly lighter atmosphere. Largemouths are more sensitive to this change in atmospheric pressure than other members of the bass family. Plan on keeping any bass you retrieve from such depths, particularly fish that show signs of buoyancy, have the stomach pushed up into the mouth, have protruding eyes, or hemorrhaged tissues.
In shallow reservoirs or ponds, bass go as deep as they can go during winter. Sometimes this isn’t deep enough; nearly the entire body of water may freeze or becomes so anoxic that fish can’t survive.
In rivers that freeze, bass seek oxygenated backwaters and avoid current. Deteriorating conditions in midwinter sometimes prompt bass to move again. Good backwater habitat is relatively rare in many rivers, so large concentrations of bass can be found wherever it occurs. In rivers that don’t freeze, bass also gather, and even at water temperatures below 40°F, good catches can be made.
Because of cold temperatures at this time of year, bass feed infrequently. They’re most active early and late in the Frozen-water Period. Ice fishermen often catch largemouths through the ice, and lunkers are common just before ice-out. Tiny lures designed for crappies often work best.
