Find oxygen and you’ll find the fish. This is the key to catching more fish during the dog days of August.
Fish need a certain amount of oxygen dissolved in the water to thrive. They’ll abandon oxygen-depleted water in summer to find the right level.
In rivers and streams, fish gravitate toward tailwaters and areas near riffles during summer, because these areas are pumping much-needed oxygen into the water.
Oxygen plays an important role in finding fish in lakes, too.
By August, most lakes in the state have formed thermoclines—this is warm water layered on top of cold water, much like what happens when you pour oil on vinegar. The thermocline, a phenomenon that only happens in summer, is where the two types of water meet. If you’ve ever dived deep into a lake and felt a cold spot, you’ve discovered the thermocline.
The warm top layer supports plants and algae, maintaining the flow of oxygen dissolving into the water. The cold layer, however, lacks oxygen. This is because decaying matter is sucking up the available oxygen.
“Fish do not have enough oxygen to live below that thermocline,” says Ted Crowell, assistant director of fisheries for the Kentucky Department of Fish and Wildlife Resources. “That should make fishing easier, because you don’t need to fish below that thermocline.”
Fish in summer want the coolest water available that still has the amount of oxygen they need. During the day, this means fishing just above the thermocline. At night, the surface temperature cools and fish move closer to the top. This is why bass fishing at night with surface lures is so effective.
In the upper end of lakes, the thermocline typically varies from 12 to 15 feet. It’s usually a few feet deeper nearer to the dam. “During summer, you’re pretty much wasting your time if you fish more than 20 feet deep in the state’s lakes,” says Crowell.
There are some exceptions. Kentucky and Barkley lakes don’t form thermoclines, while Lake Cumberland has a secondary, deep thermocline around 40 feet. Most farm ponds don’t have thermoclines.
Low-maintenance gardeners love native plants for their hardiness, but some varieties are hard to find. You’ll discover a wide selection at Kentucky Fish and Wildlife’s native plant sale August 28 in Frankfort. For more information and directions, call (800) 858-1549 during normal weekday working hours.