Date of Award

Spring 2022

Project Type

Thesis

Program or Major

Ocean Engineering

Degree Name

Master of Science

First Advisor

Jennifer L Miksis-Olds

Second Advisor

Thomas C Lippmann

Third Advisor

Kim Lowell

Abstract

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.

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