Interference with this ability threatens their survival. Loud damaging noise is made by military sonar or the detonations used in seismic testing . Some of these sounds can travel over 100km and can stress, disorientate or cause physical harm. This is a far more threatening form of pollution for whales and dolphins than previously believed. A number of recent studies have linked 'strandings' to low frequency seismic and industrial noise.
Some underwater blasts can have enough impact to cause haemorrhages in lungs and sinuses.
The impacts of seismic blasts could kill animals that were too close. Another form of noise pollution originates from fishing vessels, offshore drilling platforms and ships. The most problematic vessel sounds come from the large ships that create low frequency 'thumps' that are in the hearing range of the large baleen whales. Offshore drift nets still kill thousands of dolphins each year. Getting tangled or swallowing these plastics is becoming more common in many populations of coastal dolphins.