A software model to estimate zones of impact on marine mammals around anthropogenic noise

Anthropogenic noise impacts marine mammals in a variety of ways. In order t o estimate over which ranges this happens, we first need to understand the propagation of noise through the ocean away from the noise source, and, sec ond, understand the relationship between received noise levels and impact t hresholds. A software package combining both aspects is presented. (1) A so und propagation model based on ray theory was developed to calculate receiv ed noise levels as a function of range, depth, and frequency. (2) Current k nowledge of noise impact thresholds for marine mammals was gathered and inc luded in software routines predicting zones of impact on marine mammals aro und industrial underwater noise sources. As input parameters, this software package requires the source level and spectrum of the noise of interest; p hysical oceanography data about the local ocean environment such as bathyme try, bottom and surface loss data, and sound speed profiles; and bioacousti cal information about the target species in the form of an audiogram, criti cal auditory bandwidths, spectra of typical animal vocalizations, reported sound levels of disturbance, and criteria for hearing damage. As output, th e software produces data files and plots of the zones of audibility, maskin g, disturbance, and potential hearing damage around a noise source. (C) 200 0 Acoustical Society of America. [S0001-4966(00)04509-4].