I can’t figure out what it is I’m seeing on my sonar.  It’s not the thermocline, because it doesn’t show up in deeper parts of the lake and I marked the same thing in this area in May.  It only shows up for about a 50 yard stretch, in a spot only about 25 yards off the bank.  And it’s not weeds - I’ve dropped a bait down there and it came up clean.??‍♂️ Unit is an Echomap and I’m moving at low trolling motor speed.

Could be a weeds or Hydrilla patch, but that is awfully deep for weeds. Super clear water?

FM

Yes.  The water is quite clear - I’d estimate visibility at 8-10ft.  Weeds seem to run out most places at a max. bottom depth of 15-20ft.

Have you graphed that area at other times of the day (mid-day, late afternoon esp.) to see what it looks like? If it looks the same, it might be a cold water spring and you’re seeing the temperature difference. If it doesn’t show up later, it could be zooplankton layer.

A cold water spring is a very interesting possibility.  Never thought of that.  The lake is basically a big bowl in an area of limestone bedrock hills, so that’s entirely feasible.  

Bait? 

7 minutes ago, TnRiver46 said:

Bait? 

That was my first thought back in May, but the length and amount would be shocking so I wasn’t convinced.  Now I know for sure it’s not bait, because it’s always there in the same place. 

Shipwreck? 

Have you looked at it from another direction?  For example moving from the bank out.  

It’s a spring with a thermocline at 18’

Tom

Is there a sharp, near vertical drop off in that area? If you're running parallel to an underwater cliff and it's on the very edge of the sonar beam, it will show up as a "ghost" even though you're not right over it.

I was seeing this Sunday anywhere it was over 18 feet back in our creek , I believe this a thermocline but not 100% sure. I know the water is way colder down 10+ feet