John Harrison crappie guide on Enid

A distinct layer of water where rising warm and sinking cold water meet but do not mix. It is a layer of water where the temperature changes at least one-half a degree per foot of depth. In many of our desert bass lakes, a thermocline often develops during the spring and breaks down in the fall. The colder layer of water is often lacking in oxygen, forcing most baitfish and sport-fish to the upper layer of water. Thermoclines can be so dense that they actually show up on sonar (fish finders and depth finders) as a thick, impenetrable line.