I've seen pictures of them using Radio controlled boats for this. on some of the bigger lakes with dams on the west coast and the south. They'll put live mice on the hook and set them on the boat with the line fastened to a clothes pin, when it gets to the desired spot, give the line a jerk and the mouse is in the water. run the boat back to shore and wait. Used for big cats in the southern states to get close to the breast of the dams, as some you have to stay back a certain distance.