Based on preliminary tests on Pacific harbor seals at the Vancouver, B.C. Aquarium, Smith-Root conducted additional research on California sea lions in concert with marine mammal scientists at Moss Landing Marine Labs. Using a mild, non-lethal field of pulsed DC, tests were designed to assess the voltage gradient levels that sea lions could detect, and then to assess deterrence reactions with and without food present. Dr Jenifer Zeligs (an internationally recognized expert in marine mammal behavior) oversaw all research. In this narrated film clip, three of her California sea lions were exposed to the field at gradually increasing intensities. Deterrence was achieved even with food present. These trials demonstrate the extreme sensitivities of California sea lions to the graduated, underwater voltage gradient. They also highlight the utility of Smith-Root's technology for marine mammal deterrence in riverine areas where they are causing substantial challenges for fishery managers (salmon predation) and harbors (where pinnipeds can destroy docks, piers and sometimes boats).