Abstract: The present invention comprises apparatus designed to repel, but not injure, warm-blooded aquatic life from a specific aquatic region in an energy-efficient manner. A potential gradient is turned on and maintained between sets of immersed electrodes in response to the detection of the presence of warm-blooded animals in the "watched" volume at the surface and above and below the surface of an aquatic region. The electroshock is applied to the animal through the water by use of an electrical field generated from an array of electrodes placed in the water. The size, shape, and intensity of the electrical field are independently controlled by use of design criteria which allow the operator to determine the degree of electrical shock to be administered to a specific animal species by controlling the parameters of electrical energy induced into the animal through the water.