There is little disturbance in the pond other wise so I'm pretty sure it's being done from the shoreline. Also the bulbs of my water hyacinths were being munched on but I moved them to the center of the pond. The flowers usually stretch out within a foot or so of the edges. I have a ledge and then a drop to 3 feet. The pond isn't very big - 6 by 4 at the widest. I've attached a picture and yes, the two lilies that are in this picture are no longer there!