Behavioral Responses and Temporary Shift in Masked Hearing Threshold of Bottlenose Dolphins, Tursiops truncatus, to 1-second Tones of 141 to 201 dB re 1 Micron Pa.

Abstract : The Navy is concerned that acoustic energy emissions from various products may interfere with marine mammals. Proposed federal regulations under the Marine Mammal Protection Act discuss temporary threshold shift (TTS) as a means of evaluating impacts of those emissions. Existing Navy methods published in the Journal of the Acoustical Society of America were applied to investigate TTS in the hearing sensitivity of bottlenose dolphins (Tursiops truncatus). Changes in the dolphins' behavior were observed. These data provide a scientific basis for decisions concerning acoustic effects on marine mammals for use in preparation of environmental plans and mitigation strategies.