This invention relates to a method of and apparatus for repelling aquatic creatures and finds particular application in the protection of surfers (or surfboards) and personal watercraft such as surf skis, paddle skis and the like from shark attack. The drawing illustrates the device 10 installed on the underside of a surfboard 100, the device 10 consisting of a pair of housings 102, 104 connected to one another by a cable tray 106. One of the housings 102, 104 houses the device circuitry and the other of the housings 102, 104 houses a rechargeable power source. The device circuitry comprises electrodes connected in a circuit and adapted for immersion in a body of water, such that the water, in use, completes the circuit.