Field verification of acoustic sources of geophysical survey in shallow water conditions Free

Underwater noise generated from offshore survey is a growing concern and is known to have ecological consequences on the marine environment. As a conservation effort to reduce anthropogenic impact to the marine ecosystem, BOEM requires acoustic field verifications of sound sources used in a geophysical survey conducted in US water, to ensure the sound fields will not have detrimental effect to marine wildlife. This paper presents the field verification data from two geophysical surveys conducted in the east coast of USA in summer 2016. The survey locations were considered as area of high ecologically importance due to the close proximity to the migratory routes for a number of Baleen whale species including Fin and Northern Right whale. The recording of the survey sources were analysed spatially based on their spectral and temporal characteristics, to quantify the noise exposure experienced by a potential receptor. A comparative assessment between the sound isopleths obtained from field measurement and practical mitigation area was conducted. This information not only gives invaluable insight on the acoustic propagation in the local environment; it also provides extra confidence for the mitigation practice throughout the geophysical survey.