Growth and recovery of temporary threshold shift at 3 kHz in bottlenose dolphins: experimental data and mathematical models.
Measurements of temporary threshold shift (TTS) in marine mammals have become important components in developing safe exposure guidelines for animals exposed to intense human-generated underwater noise; however, existing marine mammal TTS data are somewhat limited in that they have typically induced small amounts of TTS. This paper presents experimental data for the growth and recovery of larger amounts of TTS (up to 23 dB) in two bottlenose dolphins (Tursiops truncatus). Exposures consisted of 3-kHz tones with durations from 4 to 128 s and sound pressure levels from 100 to 200 dB re 1 μPa. The resulting TTS data were combined with existing data from two additional dolphins to develop mathematical models for the growth and recovery of TTS. TTS growth was modeled as the product of functions of exposure duration and sound pressure level. TTS recovery was modeled using a double exponential function of the TTS at 4-min post-exposure and the recovery time.
US Navy Marine Mammal Program, SSC Pacific, Code 7151, 53560 Hull Street, San Diego, California 92152, USA.
James J
JJ
Finneran
Donald A
DA
Carder
Carolyn E
CE
Schlundt
Randall L
RL
Dear
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold; D050681:Bottle-Nosed Dolphin / Q000502:physiology*; D005260:Female; D008954:Models, Biological; D009622:Noise / Q000009:adverse effects*; D011312:Pressure; D011571:Psychoacoustics; D020127:Recovery of Function; D013997:Time Factors