Essentially what you have Ray is the lake stratifies, with "layers" of
water.

In the summer, the warm weather and increased sunlight warms the surface of
the water. This warm water is less dense and "lighter" than the colder
water from down deep. Thus, you have warm water sitting on top of the
colder levels. You can actually see the layer change on a decent locator if
you take it off automatic.

Warmer water also does not hold the same levels of dissolved oxygen that
cooler water does, and some fish prefer cooler temps, so if the lake does
stratify, many times you will find concentrations of fish right below the
layer of warm water, in the cool water with higher oxygen levels.

This whole process reverses itself in the fall, when the surface water
becomes cooler and denser. Eventually the layer of NOW warmer water cannot
support the denser, heavier water and the cooler water breaks through this
layer. In the process, it will stir up the water, which can have an effect
on the fishing. This process is called "Turnover".

I hope that this makes sense.
--
Steve @ OutdoorFrontiers
http://www.outdoorfrontiers.com
G & S Guide Service and Custom Rods
http://www.herefishyfishy.com


"QUAKEnSHAKE" wrote in message
...
Would like to know about Thermocline and how it relates to fishing. A
lake that I like "Shabbona in IL" in the map details says a Thermocline
forms in the summer around July.

Thanks Ray