Challenges in the quantitative assessment of anthropogenic sound in marine environments.

Abstract

Concerns about the effects of anthropogenic sounds in aquatic environments have increased over the past 2 decades. There is particular concern with the impact to species that are endangered or those that rely on sound for foraging, navigating, and to detect prey and predators. One of the challenges to quantitative assessment is simply characterizing all environments with potentially harmful sound sources and identifying the impacted species (type and population density). In addition, there are challenges to setting the criteria for physiological and nonphysiological (i.e., behavioral) impacts. Environments vary widely from the deep ocean where navy and commercial sonar systems mostly operate to shallow water (including rivers) where construction sites are often located and activities such as pile driving occur. There are challenges related to both the measurement and the prediction of impact in these environments. Measurements are needed to determine if sound levels and species type and density are as expected. Prediction is required to extrapolate beyond the direct measurements and to define a zone‐of‐influence to determine the overall impact. Acoustic analysis includes accurately describing the sound mechanisms and the sound propagation within the zone‐of‐influence. The focus of this presentation will be on the acoustic challenges related to quantitative assessment.