Buzz,
This time of year, oxygen isn't an issue for your pond. Water's affinity for oxygen rises as temps drop.
Water is most dense at 39 degrees, F. So, odds are high, at your north Texas lake, that surface temps are similar to temps down as deep as 6 or 8 feet.
But, water warmer than 39 degrees rises, as does water cooler than 39.
All that to say this...surface temperatures of your lake are likely similar to temperatures deeper, this time of year.
If surface temps fall below 42 degrees, deeper water temps are quick to follow.
But, the good news is this...we have had another extremely mild winter. I suspect your shad have made it, so far.
