Behavioral response study on the effects of continuous sonar on sperm whales in Norwegian waters: The S3-2016-CAS cruise report
report
There has been a significant increase of underwater anthropogenic noise in recent decades, leading to increased background noise levels and more frequent exposure of marine animals to high intensity impulse sounds such as seismic signals and naval sonar. Modern long range anti-submarine warfare surveillance sonars transmit very powerful sound pulses in the 0.1-10 kHz band. Potential negative effects of sonars on marine mammals have received particular attention after several atypical mass strandings of cetaceans in connection with naval sonar activity (D’Amico et al. 2009). These events triggered significant research effort which initially was highly focused on direct effects of noise, such as hearing impairment or neurological injury. Based on this research, accepted noise criteria for injury have been established (Southall et al. 2007). These injury criteria imply that acute effects are limited to the immediate vicinity of the transmitting source. However, behavioural responses to anthropogenic noise can also lead to other negative effects, such as habitat exclusion or cessation of important activities such as feeding, migration or reproduction. Since cetaceans generally have sensitive hearing in the frequency range of naval sonars (Popper & Ketten 2008), behavioural responses might be triggered at much lower levels than injury, and the potential for behaviourally mediated population level impacts cannot be ignored.
TNO Identifier
840271
Publisher
TNO
Collation
111 p.
Place of publication
Den Haag