The Impact of Hurricanes on the Acoustic Detection of Cetaceans

TitleThe Impact of Hurricanes on the Acoustic Detection of Cetaceans
Publication TypeThesis
AuthorsTripathy, A
Degree and ProgramMaster of Science
DegreeOcean Engineering
Number of Pages365
Date PublishedMay
UniversityUniversity of New Hampshire
LocationDurham, NH

Passive acoustic monitoring (PAM) is valuable for understanding the presence, behavior, distribution, and population density of marine mammals. While long-term variability of ambient sound is typically evaluated, the impact of short-term variability due to episodic events has not been assessed until now. Hurricanes Dorian (Category 5; 2019), Florence (Category 4; 2018), and Humberto (Category 3; 2019) impacted the soundscape as observed from the passive acoustic data at the Atlantic Deepwater Ecosystem Observatory Network (ADEON) locations in the US Mid- and South Atlantic Outer Continental Shelf. Hurricanes are increasingly prevalent in the North Atlantic and increase the ambient sound level at frequencies > 100 Hz, which may impact the detectability of cetaceans vocalizing at those frequencies. The probability of detection (Pd) of fin whales (low-frequency), minke whales (mid-frequency), and pilot whales (mid- to high frequency) was estimated at each ADEON location. Pd changed considerably during hurricane presence with site-specific impacts for each of the cetaceans, which may affect estimates of their population density from passive acoustic recordings. The findings from this study provide a baseline for impacts of episodic variability of varying intensities on signal detection, and can be translated to additional episodic events and sound sources of interest, to further enhance PAM efforts.