Q:

Has anyone ever seen this in the water? 

I'm on my phone so I hope the picture uploaded correctly.  But it's a bunch of lines in the water  and kind of circles around in the one area- it's not the same as the bubbles where fish are active.  

A:

Those are spots you can pan for ore with the Copper Pan.  Doing so you will receive copper, iron, gold, or iridium ore.