Sonar Noob question

[Mr_Fixit]

While out last weekend, I was paying very close attention to my sonar (Hook 4 chirp). I could see various (I am guessing) schools of bait fish. In some locations I was watching a rather large signal zagging up/down through the water column. I could tell it was not kelp as the kelp shows very clearly on my display, and is usually a fairly clean line at a steep angle. I was told that this could be a YT hunting? I should have snapped a picture. Next time I will.

Anyone have any samples of what YT look like in sonar?

Sorry for the noob question, but yall are the real experts here.