Over the years I have heard and read much about thermocline. Why it develops, its impact on fish, why some lakes have it and others don't, how deep it is, etc. Then I read other stories of fishermen down south fishing for crappies down 40 or more feet. It was always my understanding that a thermocline set up around 20-25 feet or so, maybe a little deeper on some lakes, maybe a little shallower on others. Supposedly there is very little fish activity below the thermocline due to oxygen levels but I'm wondering if anyone has other experiences that contradict these "gospel truths" or "old wives tales". On some lakes that go down to 80 feet I cannot pick up a thermocline on my graph, even with the sensitivity turned all the way up. Does anyone care to comment on this?