Hello OBEWAN, There is a lake not far from me called: Lake Mayfield, Tiger Muskie were introduced into it some years ago. One of the ways that they monitor the progress of these fish is to go out at night and "shock" the water as you have described. It brings the fish to the surface in a stunned state so that they can categorize them by weight, length, and other pertinent information. I was told that they do this at night due to the feeding habits of this particular species, apparently they stay deep during the day and come closer to the surface to feed at night. All pretty interesting stuff. Best regards, Allan