Underwater ears and the physiology of impacts: Comparative liability for hearing loss in sea turtles, birds, and mammals

Abstract

From human and laboratory animal studies, we have extensive knowledge about mechanisms of hearing loss from noise as well as aging, trauma, genetic conditions, and disease. By contrast, little is known about causes of hearing loss in wild species. Although there is great concern for anthropogenic acoustic impacts in marine species, especially for marine mammals, we are far from a clear understanding of the potential scope of impacts on the thousands of marine species. We have acquired significant data on hearing in pinnipeds, cetaceans, and fish, but far less is known about hearing and possible impacts in turtles and seabirds and how or if they suffer irreparable hearing loss. This talk will review what is known about hearing loss mechanisms from human and animal studies and based on the comparisons for land and marine ears, how the combined data can aid us to understand how hearing may be impaired in marine animals. It will also examine the current evidence for natural loss processes (presbycusis, disease, and trauma) in marine animals and implications for our ability to estimate and mitigate hearing loss from underwater sound.