Marine Acoustics, Inc. (MAI) modeled a seismic array and its underwater acoustic propagation during exemplar one-month exploration surveys in the Gulf of Mexico to examine marine mammal exposure estimates over a selected combination of source and animal movement parameters. Four selected marine mammal types, representing one low (LF), two mid (MF) and one high (HF) frequency members of the hearing groups defined by Southall et al. (2007), as well as two survey configurations, representing nominal 2D and 3D Airgun arrays surveys, as well as a stationary source survey, were evaluated in this parametric study. The acoustic exposure and animal response were estimated using the Acoustic Integration Model© (AIM). Four source/animal simulation cases were undertaken: (1) stationary source with stationary but diving animals, (2) moving source with stationary but diving animals, (3) moving source with moving and diving animals, and (4) moving source with moving and diving animals with aversive behaviors to received sound pressure levels (SPL). These movements were convolved with the output of the source acoustic propagation model to calculate the full 30-day exposure histories for each simulated animal for each survey configuration. These results were frequency weighted using no weighting, M-weighting (Southall et al., 2007), Navy Type II weighting (Finneran and Jenkins, 2012) and proposed NOAA guidance (NOAA, 2016). The resultant 30-day exposure histories for each animal were evaluated using both traditional metrics (unweighted 160 dB SPL for behavior, 180 dB SPL for injury) as well as a variety of TTS and PTS thresholds from Southall et al. (2007), Finneran and Jenkins (2012) and NOAA (2016). This study significantly parallels the modeling assessment presented in Ellison et al. (2016). That study provides discussion and evaluation techniques that are complementary to this report, particularly with regard to the evaluation of proportionally-scaled aversion of animals to received sound pressure levels. In Ellison et al. (2016), the full 2008 fall bowhead migration (ca. 10,000 animals) were individually assessed during a 47-day period covering the population’s westward migration past a simulation of nine selected industry noise sources that were operating in that area and time. The nominal passage time in the Ellison et al. (2016) study was approximately one week for an individual animal. The underlying objective in both of these studies was to model each individual animal (animat) continuously for the entire period of potential exposure, with a ‘dosimeter’ recording of exposure history.
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