Introduction & Objectives

Acoustically, the ocean is interconnected, and sound travels great distances. Therefore, operational noise in shallow waters may displace coastal animals and drive these species offshore (e.g. North Atlantic right whales during migration), while Navy and/or oil and gas operations may displace resident shelf-break and deep- water animals from important habitats. However, shifts in distribution of animals may also occur due to ecological changes, independent of anthropogenic activities. Teasing apart the drivers of these changes can only be done through a clear, well-designed project with a multi-year dataset that enables inference to be drawn before, during and eventually after operations, as well as between sites with low (controls) and high operational activity.

Acoustically sensitive species such as beaked whales inhabit the North Atlantic shelf break region, and all ESA-listed baleen whales, such as the North Atlantic right whale (Eubalaena glacialis), fin (Balaenoptera physalus), blue (Balaenoptera musculus), and sei whales (Balaenoptera borealis) are known to use this area to different extents. NOAA’s Northeast Fisheries Science Center and Scripps Institution of Oceanography (SIO) collaboratively deployed long-term high-frequency acoustic recording package (HARP) passive acoustic monitoring stations at eight sites along the western North Atlantic shelf break from 2015 to 2019 in coordination with the Bureau of Ocean Energy Management (BOEM). Likewise, the US Navy monitored the shelf break region at 3 to 4 sites from 2007 to 2022. Together these combined efforts bring the total to 11 recording sites spanning the U.S. eastern seaboard, from New England to Georgia.rics

Technical Approach

HARPS were deployed at 11 sites by the NEFSC and U.S. Navy along the Atlantic continental shelf break of the U.S. beginning as early as 2015. The sites deployed starting in 2015 include Heezen Canyon, Oceanographer Canyon, Nantucket Canyon (three northernmost sites), Norfolk Canyon, Cape Hatteras, and JAX (U.S. Navy deployments). These were expanded in 2016 to include Wilmington and Babylon Canyons north of Cape Hatteras as well as Gulf Stream, Blake Plateau, and Blake Spur south of Cape Hatteras. Each HARP was programmed to record continuously at a sampling rate of 200 kilohertz (kHz) with 16-bit quantization, providing an effective recording bandwidth from 0.01 to 100 kHz. Further details of HARP design are described in Wiggins and Hildebrand (2007).

Analysis of passive acoustic data utilizes manual analysis or specialized detectors, unsupervised learning and neural networks, and other methods. Programs used include MATLAB, Triton, and others.

Progress & Results

Analysis under this effort varies by year as analytical components for key objectives are advanced. Work conducted in 2024 was aimed at finalizing components for these key objectives:

• Analyze beaked whale presence across HARP sites, with a focus on northern bottlenose whale and BWG presence.
• Assessing effects of anthropogenic noise on beaked whale vocal activity
• Analyze minke whale presence on the Navy HARP sites
• Revising a manuscript comparing and contrasting two passive acoustic monitoring methodologies - towed array and shelf break HARPs - concerning beaked whale temporal, spatial presence and diving behavior.
• Submit a manuscript that utilizes passive acoustic data from ten shelf-break environments to evaluate composition and dissimilarity of marine mammal community groups at different latitudes.
• Submit a manuscript describing the methodology of the beaked whale neural net classifier to be cited in future publications utilizing this approach
• Submit a manuscript comparing and contrasting two PAM methodologies—towed array and shelf break HARPs—concerning beaked whale temporal, spatial presence, and diving behavior
• Utilize passive acoustic data from 10 shelf-break environments to evaluate composition and dissimilarity of marine mammal community groups at different latitudes

For more information regarding this study, refer to the annual progress report for this project (Van Parijs et al. 2024).

Presentations & Publications

Combining Spatial and Temporal Acoustic Datasets to Examine the Summer Presence of Beaked Whales Off the East Coast of the U.S. (SMM 2022)

Monitoring the acoustic ecology of the shelf break of Georges Bank, Northwestern Atlantic Ocean: New approaches to visualizing complex acoustic data (Marine Policy, 2021)

Exploring movement patterns and changing distributions of baleen whales in the western North Atlantic using a decade of passive acoustic data (Global Change Biology, 2020)

Spatial and seasonal patterns in acoustic detections of sperm whales (Physeter macrocephalus) along the continental slope in the western North Atlantic Ocean (Endangered Species research, 2018)

Using passive acoustic monitoring to document the distribution of beaked whale species in the western North Atlantic Ocean (Canadian Journal of Fisheries and Aquatic Sciences, 2017)

Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014 (Scientific Reports, 2017)