I was doing ecological work in a lake when we came under spudgun fire. Someone (kids?) began slowly firing from a distant treeline on the side of one of the hills that surrounded the lake. I knew the distinctive thump, so I was looking out for the first splash, which ended up being much closer than I expected it to be! I had assumed they would be aiming somewhere else. I informed my shipmates that we were under attack and we rowed to shore as fast as possible. They got in about three or four shots, but we escaped injury and no one was ever caught.