Twice this spring/summer I have witnessed a phenomenon I have never seen before, and maybe some of you with a biological background can shed some light on it. Anyway, myself and sons have seen a small area of the surface about 20-30' from shore (perhaps 6'x 6') on two separate lakes rise up about 2" and move a short distance before dissipating. The water seems to almost boil and appears to be shimmering when this happens. It is shallow water, so there could be no beast like a beaver or muskrat underneath to cause the surface disturbance. Nothing happens afterwards either. It has happened so quickly and unexpectedly on both occasions that I was not fast enough to get a photo. When we witnessed these occurences, we were left kind of awestruck. My guess is that it is a bait ball of stickleback getting chased by a school of trout. Any other ideas?