Jackets are becoming standard attire for those who fish Lake Lanier during the early morning or late evening hours. The surface temperature has finally dropped below 80 degrees, the feeding binge for bass and other predators has begun and the lake is showing the first signs of the annual renewal process known as fall turnover.
Though turnover can be a period of turmoil below the surface of a lake, this is an excellent period for knowledgeable fishermen. The turnover process is actually quite simple, but few anglers really understand this yearly change. As the water cools, it becomes denser or heavier and begins to sink. The warmer, lighter water below is then forced to rise to the top where it is also cooled, and the process continues until the thermally-layered waters of summer are homogenized throughout the reservoir. This metamorphosis also mixes the oxygen-rich water above the thermocline with the poorly oxygenated water in the colder depths, which gives the lake a renewed capacity for life from top to bottom. Rains associated with cold fronts accelerate this process.
Recognition of the turnover process can be as simple as the use of one’s senses of sight and smell. Usually a change of color in the water near the surface can be seen. The water will have a brownish tint to it and often smell like rotten eggs or decaying vegetation as the turnover brings the bad water at the bottom of the lake to the surface.
The poorly-oxygenated water that is being pushed upwards from the floor of the lake temporarily trashes the whole system. Therefore, the key to success is to find good quality water.
One of the easiest ways to locate good water is to look for creeks with fresh water running into them. Another solution is to go directly to the nearest producer of oxygenated water, which is normally surface aeration from wind and waves. The oxygen on windward banks will stack up to five or six feet deep, while the leeward shoreline may contain only a foot of oxygenated water. Since baitfish are more susceptible to oxygen depletion than bass and tend to be blown with the wind, when numerous schools of them are found in the shallows, it’s a positive sign. Predator fish that feed on these schools of shad can generally be caught with horizontal-running lures that imitate the size and shape of these baitfish.
On a deep, clear lake like Lanier, sometimes the worst cold front will cause the feeding fish to go into a frenzy. When that happens, they would eat their own mother, and the fishing is so good, anglers become spoiled.
Fall turnover always ushers in a time of change in the aquatic environment, but it is also a period of renewed activity. Fish must adjust their habits to compensate for this upheaval in their underwater world, and for those anglers who acquire an understanding of this annual phenomenon, this feeding binge can be one of the best times of year to experience the joys of fishing!