Print Email Facebook Twitter Lack of reproducibility of temporary hearing threshold shifts in a harbor porpoise after exposure to repeated airgun sounds Title Lack of reproducibility of temporary hearing threshold shifts in a harbor porpoise after exposure to repeated airgun sounds Author Kastelein, R.A. Helder-Hoek, L. Cornelisse, S.A. von Benda-Beckmann, A.M. Lam, F.P.A. de Jong, C.A.F. Ketten, D.R. Publication year 2020 Abstract Noise-induced temporary hearing threshold shift (TTS) was studied in a harbor porpoise exposed to impulsive sounds of scaled-down airguns while both stationary and free-swimming for up to 90 min. In a previous study, ∼4 dB TTS was elicited in this porpoise, but despite 8 dB higher single-shot and cumulative exposure levels (up to 199 dB re 1 μPa2s) in the present study, the porpoise showed no significant TTS at hearing frequencies 2, 4, or 8 kHz. There were no changes in the study animal's audiogram between the studies or significant differences in the fatiguing sound that could explain the difference, but audible and visual cues in the present study may have allowed the porpoise to predict when the fatiguing sounds would be produced. The discrepancy between the studies may have resulted from self-mitigation by the porpoise. Self-mitigation, resulting in reduced hearing sensitivity, can be achieved via changes in the orientation of the head, or via alteration of the hearing threshold by processes in the ear or central nervous system. © 2020 Acoustical Society of America. Subject MammalsCentral Nervous SystemsCumulative ExposuresFree SwimmingHarbor PorpoiseHearing SensitivityHearing ThresholdImpulsive SoundsAuditionAir GunArticleAudiographyAuditory ThresholdCentral Nervous SystemControlled StudyEarHearing AcuityNonhumanPhocoena PhocoenaReproducibilitySound To reference this document use: http://resolver.tudelft.nl/uuid:b5ffeee9-772e-4030-b476-2178bbdfdc01 TNO identifier 880118 Publisher Acoustical Society of America ISSN 0001-4966 Source Journal of the Acoustical Society of America, 148 (2), 556-565 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.