batch_auto_20260713 202607131256465730 BOEM ESP geoESPIS ESPIS@boem.gov Bureau of Ocean Energy Management Fish Auditory Thresholds - Part 1 National Marine Fisheries Service, Northeast Fisheries Science Center National Marine Fisheries Service, Northeast Fisheries Science Center One of the most prevalent, yet poorly understood, sublethal effects of underwater noise is auditory masking. This is where a receiver experiences an increase in the threshold of acoustic detection or discrimination of a signal that could potentially lead to partial or complete loss of received signal, misinterpretation of the signal, and/or changes in a response, due to an unwanted masking noise containing sufficient energy inside the detectible frequency range. This study examines the response of black sea bass and squid to pile driving sound using playbacks of recorded sound within a tank environment. Black sea bass exposed to the sound altered their behavior, including reduced activity. Additionally, black sea bass display diminished behavioral response within an exposure period, which could indicate habituation, however, with increased responses among exposure periods (one - three), which could indicate re-sensitization. All squid exposed to pile driving noise responded with alarm behaviors, indicating squid detected and were dramatically influenced by this noise. The reduction in alarm responses over several noise impulses indicates increased tolerance over time to the noise source and suggests these squid may have behaviorally habituated. 1000000 U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program https://doi.org/10.13039/100012475 M17PG00029 10.67297/9A1DEA https://boem.gov/awardpages/100202