Implementation of a method to visualize noise-induced hearing loss in mass stranded cetaceans

Morell, M., Brownlow, A. , McGovern, B., Raverty, S.A., Shadwick, R.E. and André, M. (2017) Implementation of a method to visualize noise-induced hearing loss in mass stranded cetaceans. Scientific Reports, 7, 41848. (doi: 10.1038/srep41848) (PMID:28165504) (PMCID:PMC5292969)

Abstract

Assessment of the impact of noise over-exposure in stranded cetaceans is challenging, as the lesions that lead to hearing loss occur at the cellular level and inner ear cells are very sensitive to autolysis. Distinguishing ante-mortem pathology from post-mortem change has been a major constraint in diagnosing potential impact. Here, we outline a methodology applicable to the detection of noise-induced hearing loss in stranded cetaceans. Inner ears from two mass strandings of long-finned pilot whales in Scotland were processed for scanning electron microscopy observation. In one case, a juvenile animal, whose ears were fixed within 4 hours of death, revealed that many sensory cells at the apex of the cochlear spiral were missing. In this case, the absence of outer hair cells would be compatible with overexposure to underwater noise, affecting the region which transduces the lowest frequencies of the pilot whales hearing spectrum. Perfusion of cochlea with fixative greatly improved preservation and enabled diagnostic imaging of the organ of Corti, even 30 hours after death. This finding supports adopting a routine protocol to detect the pathological legacy of noise overexposure in mass stranded cetaceans as a key to understanding the complex processes and implications that lie behind such stranding events.

• Item Type: Articles
• Additional Information: This study was funded by Marine Scotland reference MLS/EJN/2073561, the Spanish Ministry of the Environment under contract 083/SDGTB/2007 and Canadian Natural Sciences and Engineering Research Council Discovery and Accelerator grants RGPAS 446012-13 and RGPAN 312039-13.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Brownlow, Dr Andrew
• Authors: Morell, M., Brownlow, A., McGovern, B., Raverty, S.A., Shadwick, R.E., and André, M.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © The Author(s) 2017
• First Published: First published in Scientific Reports 7:41848
• Publisher Policy: Reproduced under a Creative Commons licence