It also looks like you may have something on the bottom of the left side of your hull (throughull for live well maybe?) that is causing some surface turbulence on the left side. What was your speed during that scan? You may need to slow down.
OK, I just noticd the two through hull fittings in the centre of the transom. My bet is that they are creating turbulence that is causing the lines. In fact, you can see the turbulence on the left side at the top of the water column. Speed may be a factor. try slowing down when scanning.