The relationship between underwater sounds generated by pile driving and fish physiological responses

Abstract

Assessment of fish physiology after exposure to impulsive sound has been limited by quantifying physiological injuries, which range from mortal to recoverable. A complex panel of injuries was reduced to a single metric by a model called the Fish Index of Trauma. Over several years, six species of fishes from different morphological groupings, (e.g., physoclistous, physostomous, and lack of a swim bladder) were studied. The onset of physiological tissue effect was determined across a range of cumulative sound exposure levels with varying number of pile strikes. Follow up studies included investigation of healing from incurred injuries. The level of injury that animals expressed was influenced by their morphological grouping. Finally, investigation of the inner ear sensory hair cells showed that damage occurred at higher sound exposure levels than when the onset of tissue injury would occur.