Many marine organisms rely on their ability to hear for their survival. Sound is ahighly efficient means of communication underwater and is the primary way that manymarine species gather and understand information about their environment. Manyaquatic animals use sound to find prey locate mates and offspring avoid predatorsguide their navigation and locate habitat as well as to listen and communicate witheach other. Oceans are full of sound. Waves, earthquakes and icebergs - allcontribute to the underwater soundscape. But so do human activities and this can bea problem for marine life as it can seriously affect their physiology behaviour,reproduction and even survival. Being able to produce and detect sound in anenvironment where light penetrates only a few hundred metres is crucial for animalsto communicate, feed, avoid predators and navigate vast underwater habitats. Largewhales generate low frequency communication calls that can travel thousands ofkilometres. While the snapping shrimp, native to the western Atlantic, can producea loud snapping sound capable of stunning and killing its prey. The noise generatedby humans changes the natural acoustic environment of our oceans and our capacityto produce it is increasing. Noise is often the unintentional by product oftransport infrastructure development and industry. Yet noise can also be produceddeliberately. Many navies use sonar system to detect ships and submarines whilegeologists survey the seabed for oil and gas using seismic airguns. The noiseproduced by an airgun can exceed 200 decibels louder than a gunshot at a range ofone metre. Sound travels further and four times faster in water than in air at aspeed of almost 1500 metres per second. The noise produced by humans can thereforespread considerable distances underwater. These sounds can be relatively constantsuch as the noise produced by the engine of a ship and propeller or sudden andacute in the case of naval sonar and seismic airguns