Passive acoustic monitoring was conducted using High-frequency Acoustic Recording Packages (HARPs) deployed in waters offshore of Virginia, North Carolina, and Florida with support from the US Navy during 2016 - 2017. The HARPs recorded underwater sounds between 10 Hz and 100 kHz. Data analysis consisted of analyst scans of long-term spectral averages (LTSAs) and spectrograms, and automated computer algorithm detection when possible. Three frequency bands were analyzed for marine mammal vocalizations and anthropogenic sounds: (1) Lowfrequency, between 10-1000 Hz, (2) Mid-frequency, between 1,000-5,000 Hz, and (3) Highfrequency, between 1-100 kHz.

The United States (US) Navy uses lookouts (LOs) to detect objects in the water in the vicinity of ships. One class of object that LOs are trained to detect is marine mammals ; this forms an important component of the Navy’s procedures for marine mammal mitigation during training activities . As well as dedications of marine mammals by these LOs, detections of marine mammals may also be made by other members of the ship’s crew such as officers on the bridge (“watchstanders”) or sonar technicians, although acoustic detections require visual confirmation. We refer to these personnel together as the “lookout team” (LT). The primary goal of this project was to determine how effective LTs are at detecting marin

Long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break.