I have been going out to the Mississippi in Tn and the side I'm on there are rock and the other side is a big sand bar. The past few times out we have been hearing monsterous splashing sounds coming from the sand bank. At first I thought it was sand collapsing, but a guy told me it was fish coming up on the band and rolling in the sand to get leaches off of them and clean their coat. Has anyone heard of this? Is it true?