Mapping the Soundscape Off the SoutheasternUSA by Using Passive Acoustic Glider Technology

The purpose of this study was to explore the soundscape of shelf-edge Atlantic waters of the southeastern USA (SEUS) during winter by using passive acoustic and autonomous glider technologies, with a focus on the distribution of groupers. An autonomous glider was deployed off the SEUS coast near Cape Canaveral, Florida, on March 3, 2014, and transited to Cape Fear, North Carolina, where it was retrieved on April 1, 2014. Using satellite and hydrodynamic model data for guidance, the glider piloted in and out of the Gulf Stream, taking advantage of the high currents to reach the targeted sampling area. Ambient noise was recorded by an integrated passive acoustic recorder during the 29-d mission, in which the glider traveled 895 km and reached waters 267 m deep. A variety of sounds was identified in the acoustic recordings, including sounds generated by Red Grouper Epinephelus morio and toadfishes Opsanus sp.; two sounds previously documented in the Gulf of Mexico that were suspected to be produced by fish; whistles and echolocation from marine mammals; and extensive vessel noise. Numerous sounds from previously undocumented sources were also recorded. The Red Grouper was the only serranid that was consistently identified from the sound data, with detections occurring within and outside of South Atlantic Fishery Management Council marine protected areas. This research demonstrates the potential utility of a glider-based passive acoustic approach as a component of a program to map fish, marine mammal, and vessel distributions over large scales