There has been concern about the possible effects on marine life of acoustic disturbance from seismic surveys and other operations where acoustic energy is released. Modern large-scale surveys are carried out using towed arrays of ‘air-guns’ - compressed air cylinders which are discharged simultaneously causing a pressure pulse which travels down into the seabed. Little is known about the extent to which these procedures may affect cetaceans. However, being inquisitive and attracted to areas of human activity may increase the risk to these mammals. In the worst case, there is some risk of physical damage if cetaceans are close to discharging air guns, but there is no evidence that this has occurred in UK waters. These guidelines set out procedures to help minimize the risks of acoustic disturbance. Their application is required in some sea areas but member companies of the UK Offshore Operators Association and the International Association for Geophysical Contractors will be applying them in all waters of the UK continental shelf.