Looks like a school of yellowtail underneath you
And it looks like you're about to get bit.
If it's constant, change your settings. On a lake it's easy to get closer than you would on the ocean. You may not be "too close" respect wise, but you could be picking up interference from another boat's fish finder. If your beams cross, it would show diagonal lines like yours is displaying.
The pump could also cause the disturbance but only if it's super close to the transducer. Make sure nothing is aft of the transducer. I try to keep mine mounted as far back as I can. It could also be your paddle turbulence.