I saw a post about thermocline, what is it and what does it mean? From what I gather it's a temperature in the water that affect how deep or shallow bass go. Please can some one explain better!?

In fluid dynamics... Nevermind...

It is the line in which the gradual temperature change from depth hits a critical mass where the drop in temperature is greater. The temperature differential is not why the bass don't like to go below it. It has everything to do with decomposing matter and bacteria that reduce oxygen in the cold dark water.

Don't believe me, I am no scientist, so...

-on!

Google will be a good next step.

Here's a pic of what it looks like. Look near the bottom and it's the fog looking line.

Here is a good article.

http://en.wikipedia.org/wiki/Thermocline

. So fish stay above this line? Thanks for the info

Usually, yes. Water below the thermocline can't mix with the warmer, and lighter, surface water. The water below the thermocline often, but not always, has lower concentrations of dissolved oxygen because there is not as much (or any) oxygen production at depths and decomposition of dead organic material consumes oxygen. There are always exceptions, but this is common in murky productive lowland lakes.

On the topic of thermocline: Does anyone know how riverine lakes with movement of water ie. dam releases and such effect the water. To me it seems it would mix well but that is just a guess. Im talking lake Austin in particular here.

Remember that the thermocline moves. It doesn't just move up and down depending on water temperature, either. It's not like a sheet of steel down there. Instead, think of a gigantic American flag that is waved by dozens of people holding its edges over football a field, or perhaps a huge sheet of very light aluminum foil held over a floor with small fans blowing under it. The surface of the thermocline bellows up and down like the flag/foil, only more slowly. Current can move it, too.

A rock on a point could be just above the thermocline at 2:00 p.m, but be below it a half hour later - especially on a windy day. Sometimes, the biggest bass will hold on structure and/or cover where it meets the thermocline. Not below it, but just above it. Here in Texas, that pretty much happens only during the hottest summer months and into the early fall.

The type of dam makes a difference. Overflow dams have little effect on the stratification of the lake upstream. However, dams that release water from near the bottom of upstream lakes can reduce the volume of water below the thermocline. The cold water still doesn't mix with the warmer water above it, but there's less cold (unproductive or hypoxic) water in the lake. In theory, drawing water from the bottom of a lake can increase the volume of productive water above the thermocline, therefor increasing the overall productivity of the lake.

If there's a great deal of flow, like natural river velocities, it's possible to not have a thermocline at all. But, if the water ever stops moving, a thermocline will develop fairly quickly. Once it's in place, it's extremely stable. And to clarify, in agreement with the poster right above me, I mean that it is very difficult to break the stratification, not that it is set at that exact depth forever. It can shift daily and be pushed around by current.

Outstanding answer yall. Thank you very much.

The thermocline is a good pattern. Search where the thermocline meets the bottom like this. Sure thing !!!!!!!


Note the fish under the 3 in the depth readout:



Similar setup--fish behind the temp readout:

For what it's worth, a professional angler told me once to always stay above the thermocline when targeting bass. That being said, I have a hard time finding the thermocline on my graph. It doesn't show up real well.

ANY properly adjusted sonar unit will display the thermocline IF there is one present.
I used to use the thermocline pattern "back in the day" of flasher sonars.
With a remote temp sensor, you can determine its depth when the temp reading changes one degree per foot of depth change.

Another example of a thermocline with 2D sonar and Imaging:

Lake Austin does not create a thermocline to my knowledge except for maybe around the dam at LBL. It's water temp stays cool because of the sub cooled water released from Travis. If anyone knows different chime in.

Great pics wayne!!

I can apply that right away!! Know a spot just like you pictured.