Auditory masking of tonal and conspecific signals by continuous active sonar, amplitude modulated noise, and Gaussian noise in killer whales (Orcinus orca)
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View abstract on PubMed
Summary
This summary is machine-generated.Continuous active sonar (CAS) poses a significant auditory masking risk to killer whales, despite its lower sound pressure. CAS spectral features overlap with whale calls, hindering their communication and detection abilities.
Area Of Science
- Marine biology
- Bioacoustics
- Acoustic oceanography
Background
- Continuous active sonar (CAS) is used by navies, potentially impacting marine mammals.
- While CAS has lower sound pressure than pulsed sonar, its continuous nature may increase auditory masking.
Purpose Of The Study
- To evaluate the auditory masking potential of CAS on killer whale signal detection.
- To compare CAS masking with other noise types like amplitude-modulated and Gaussian noise.
Main Methods
- Two killer whales were tested for signal detection in the presence of different noise types.
- Signals included a 1.5 kHz pure tone and a killer whale vocalization.
- Noise types were continuous active sonar, amplitude-modulated noise, and Gaussian noise.
Main Results
- All noise types caused significant masking of the 1.5 kHz tone, with amplitude-modulated noise showing a 13 dB release from masking.
- Killer whales used an off-frequency listening strategy for their calls, but this was less effective against CAS.
- CAS noise effectively masked killer whale calls due to spectral overlap.
Conclusions
- Continuous active sonar presents a considerable auditory masking risk to killer whales.
- The spectral characteristics of CAS interfere with killer whale communication and detection.
- Further research is needed to understand and mitigate the acoustic impacts of sonar on marine life.
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