Document ID: chunk:federal_register_of_legislation:F2015L01633:body:0:p26
Version: federal_register_of_legislation:F2015L01633
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are likely capable of hearing outside their vocal range60. Given this lack of defined sensitivity for blue whales it is difficult to accurately assess whether a particular type of man-made sound would affect blue whales.
Masking by anthropogenic noise can become a concern for a particular cetacean species when the frequency band of the noise overlaps with the species' vocal frequency range or hearing range. The importance of sound to marine mammals means anthropogenic noise can create changes in their behaviour, vocalisations and physiology84. Many different anthropogenic noise sources have been shown to affect cetaceans and these are summarised below with specific reference to blue whales49,84.
Seismic surveys
Seismic systems use sound to actively image geological structures below the seafloor. Marine seismic surveys are a method of locating and describing marine oil and gas deposits. This is often undertaken by using air gun arrays towed off ships to release air downward under pressure, producing powerful (up to 260 dB re: 1 µPa @ 1 m) and predominately low frequency (5 to 300 Hz) sound waves typically repeated in ~10 s intervals49. Impulsive sounds such as these present a greater risk than most continuous sounds because of the high peak levels and frequent repetition.  Note that while the level of the anthropogenic sound is usually reported at 1m from the source as is standard, it is the level of the sound when received by the individual that is relevant for the whale (but this value is more difficult to determine). At lower received levels other responses may occur such as displacement and other behavioural responses32.
The risk of physical impacts is minimised by implementation of the practical measures outlined in the  EPBC Act Policy Statement 2.1 – interaction between offshore seismic exploration and whales. While the seismic guidelines advise that seismic surveys should be undertaken outside of biologically important areas at biologically important times, it is not known at what distance from a seismic source, behavioural impacts may occur or the extent of any behavioural impact.

Acute and chronic industrial noise
Acute noise comes from activities such as pile driving, use of explosives, blasting, some forms of dredging and sonar. Sources of chronic industrial noise include drilling, tender vessels, laying pipelines etc (a continuous, loud noise in the marine environment). The construction, operation and decommissioning of coastal and offshore oil and gas platforms or floating processing facilities, marinas and ports, and marine renewable energy facilities create large amounts of varied underwater noises from a wide range of activities. They also create additional shipping traffic especially around marinas and ports, and additional helicopter activity around oil and gas platforms to transport personnel. Such developments are subject to the EPBC Act in Australia.