title: Behavioral responses of two captive bottlenose dolphins (Tursiops truncatus) to a continuous 50 kHz tone.
abstract: At present, the fundamental frequencies of signals of most commercially available acoustic alarms to deter small cetaceans are below 20 kHz, but it is not well ascertained whether higher frequencies have a deterrent effect on bottlenose dolphins (Tursiops truncatus). Two captive bottlenose dolphins housed in a floating pen were subjected to a continuous pure tone at 50 kHz with a source level of 160 ± 2 dB (re 1 μPa, rms). The behavioral responses of dolphins were judged by comparing surfacing distance relative to the sound source, number of surfacings, and number of echolocation clicks produced, during forty 15 min baseline periods with forty 15 min test periods (four sessions per day, 40 sessions in total). On all 10 study days, surfacing distance and the number of surfacings increased while click production decreased during broadcasts of test sound. The avoidance threshold sound pressure level for a continuous 50 kHz tone for the bottlenose dolphins, in the context of this study, was estimated to be 144 ± 2 dB (re 1 μPa, rms). The results indicated that a continuous 50 kHz tonal signal can deter bottlenose dolphins from an area.
authors.affiliation: Open Laboratory of Ocean Acoustic and Remote Sensing, Third Institute of Oceanography, State Oceanic Administration, College of Oceanography and Environmental Science, Xiamen University, 422 Road, Xiamen 361005, People's Republic of China.
authors.forename: Fu-qiang
authors.initials: FQ
authors.lastname: Niu
authors.forename: Zhen-wen
authors.initials: ZW
authors.lastname: Liu
authors.forename: Hong-tao
authors.initials: HT
authors.lastname: Wen
authors.forename: De-wei
authors.initials: DW
authors.lastname: Xu
authors.forename: Yan-ming
authors.initials: YM
authors.lastname: Yang
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D050681:Bottle-Nosed Dolphin / Q000502:physiology*; D004455:Echolocation / Q000502:physiology; D008297:Male; D009622:Noise; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000502:physiology