Abstract: A method and apparatus for controlling aquatic animals, particularly sharks. Electrodes are immersed in a body of water and an electric field is created between the electrodes by applying electrical pulses thereto. The pulses may have a duration of between 0.1 and 200 ms, a repetition rate of between 1 and 60 Hz, and a field strength in the body of water at a distance of 1 m of 1 to 10 V.m.sup.-1 from the electrodes. In a preferred form of the invention, the pulses are generated in pulse trains each comprising a plurality of pulses, with each pulse having a duration of between 0.1 and 3 ms, the pulses in each train being spaced at intervals of between 1 and 30 ms, and the pulse trains being repeated at intervals of between 100 and 1000 ms. In a specific form of the invention, each pulse in such a pulse train has a duration of 2 ms, the pulses in each train are spaced at intervals of 20 ms and the pulse trains are repeated at a frequency of between 2 and 5 Hz.