Comprehensive summary of the impulsive pile driving sound exposure study series

The high intensity controlled impedance fluid filled wave tube (HICI-FT) was used to expose fishes, in the laboratory, to impulsive sound signals under controlled conditions. Fish species were exposed to pile driving signals under different experimental paradigms, followed by detailed investigations of their physiological tissue response (aka, barotrauma injuries). Most often the cumulative sound exposure level (SELcum) was held constant while varying the number of pile strikes and the single strike sound exposure level (SELss). Altering these three variables proved the equal energy hypothesis irrelevant; the higher SELss values with fewer number of strikes caused a highest injury levels. The first dose-response curve was generated for fish responses. Comparisons between different species showed fish with no swim bladder at low injury risk, fish with a closed swim bladder (physoclists) at a high injury risk, and fish with an open swim bladder (physostomes) at a moderate injury risk. If fish find safe haven in the wild, they have potential to heal within 10 days of receiving moderate injuries. Tissue injury appears to occur before damage to hair cells occurs. And most recently, fish show injury after exposure to as few as 8-impulsive signals that have a high SELss value.