A combination of machine learning and expert analyst review was used to detect odontocete echolocation clicks, identify dominant click types, and classify clicks in 32 years of acoustic data collected at 11 autonomous monitoring sites in the western North Atlantic between 2016 and 2019. Previously-described click types for eight known odontocete species or genera were identified in this data set: Blainville’s beaked whales (Mesoplodon densirostris), Cuvier’s beaked whales (Ziphius cavirostris), Gervais’ beaked whales (Mesoplodon europaeus), Sowerby’s beaked whales (Mesoplodon bidens), and True’s beaked whales (Mesoplodon mirus), Kogia spp., Risso’s dolphin (Grampus griseus), and sperm whales (Physeter macrocephalus)

This report forms part of a multi-institutional monitoring project intended to provide information on the species composition, population identity, density, and baseline behavior of marine mammals and sea turtles present in United States (U.S.) Navy range complexes along the U.S. Atlantic Coast.

This report forms part of a multi-institutional monitoring project intended to provide information on the species composition, population identity, density, and baseline behavior of marine mammals and sea turtles present in United States (U.S.) Navy range complexes along the U.S. Atlantic Coast.

Passive acoustic monitoring was conducted within the Navy’s Cherry Point OPAREA during August – December 2011 and July – October 2012 for a total of 105 and 81 days respectively. This site is located approximately 100 miles from the North Carolina coastline on the shelf break. The 2011 deployment was at a water depth of 952 m and the 2012 deployment was at a water depth of 914 m. Acoustic data collected at this site provide information on the presence of marine mammals and anthropogenic sound sources. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz with recording cycles of 5 minutes every 10 minutes. The data were divided into three frequency bands and data were analyzed by scans of long-term spectral averages and spectrograms. Four baleen whale species were recorded: blue, fin, minke, and sei whales. The detections of their calls were made between late August and early December 2011. Blue whale calls were the only baleen whale call type detected in the 2012 deployment. No Bryde’s, humpback, or North Atlantic right whale calls were detected in either deployment. Several different toothed whale species were recorded: Blainville’s, Cuvier’s, and Gervais’ beaked whales, killer whales, pygmy or dwarf sperm whales (Kogia spp.), Risso’s dolphins, sperm whales, and unidentified odontocetes. All species except killer whales were recorded in 2011 and 2012. Killer whales were detected only in 2011. Ship noise was the most common anthropogenic sound in both deployments. MFA was noted during both deployments. A total of 391 pings were detected in 2011 with a maximum peak-to-peak received level of 156 dB re 1 μPa. In 2012, a total of 492 pings were detected with a maximum peak-to-peak received level of 167 dB re 1 μPa. Few echosounder pings over a variety of frequencies (4-80 kHz) were detected during both deployments. Explosions were detected in both deployments, though they were more prevalent in 2011 than 2012. High noise levels, possibly caused by instrument strumming and fluid flow at the sensor, occurred intermittently in both deployments and likely decreased the detection range for low-frequency sounds. This strumming was most prevalent in 2012.

In the Pacific, the Marine Mammal Monitoring on Navy Ranges (M3R) program maintains systems that continuously run algorithms to detect, classify and localize marine mammals year-round on the U.S. Navy’s deep-water Southern California Antisubmarine Warfare Range (SOAR) in Southern California and the Pacific Missile Range Facility (PMRF) off Kaua‘i, Hawai‘i. Long-term archive data collected on these ranges allow for numerous types of studies on species inhabiting the ranges, including the monitoring of abundance, behavioral responses to naval activities, and habitat usage. They also provide the opportunity to study ambient sound levels and soundscapes.

To monitor for the presence of marine mammals, a High-frequency Acoustic Recording Package (HARP) recorded within the Navy’s Virginia Capes Range Complex, offshore from Cape Hatteras (HAT), between April 2015 and January 2016. The HAT site was located approximately 75 nm offshore in about 1000 m of water.

Beaked whales (family Ziphiidae) consist of at least 21 different species in six genera with relatively little known about many of the species. Research on this family of odontocetes has increased in the last two decades as a result of a mass stranding event of beaked whales in the Bahamas in 2000 in association with a U.S. Navy training event. Results of this research have identified echolocation click characteristics for several species from different areas of the world based upon both tag data and passive acoustic monitoring data

Passive acoustic monitoring was conducted using High-frequency Acoustic Recording Packages (HARPs) deployed in waters offshore of Virginia, North Carolina, and Florida with support from the US Navy during 2016 - 2017. The HARPs recorded underwater sounds between 10 Hz and 100 kHz. Data analysis consisted of analyst scans of long-term spectral averages (LTSAs) and spectrograms, and automated computer algorithm detection when possible. Three frequency bands were analyzed for marine mammal vocalizations and anthropogenic sounds: (1) Lowfrequency, between 10-1000 Hz, (2) Mid-frequency, between 1,000-5,000 Hz, and (3) Highfrequency, between 1-100 kHz.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between August 2011 and July 2012 in Onslow Bay at Site E in 952 m. This HARP sampled at 200 kHz for 5 minutes of every 10 minutes and recorded for 105 days between 19 August 2011 and 1 December 2011. Long-Term Spectral Averages (LTSAs) were created for three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations. Calls of blue whales, fin whales, minke whales, possible sei whales, an unidentified beaked whale species, Blainville’s beaked whales, Cuvier’s beaked whales, Gervais’ beaked whales, killer whales, Kogia spp., Risso’s dolphins, sperm whales, and unidentified delphinids were detected in the data.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between July and October 2012 in Onslow Bay at Site E in 914 m. This HARP sampled at 200 kHz for 5 minutes of every 10 minutes and recorded for 81 days between 14 July 2012 and 2 October 2012. Long-Term Spectral Averages (LTSAs) were created for three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations. Calls of blue whales, Blainville’s beaked whales, Cuvier’s beaked whales, Gervais’ beaked whales, Kogia spp., Risso’s dolphins, sperm whales, and unidentified delphinids were detected in the data.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between October 2012 and August 2013 in Onslow Bay at Site E in 853 m. This HARP sampled at 200 kHz for 5 minutes of every 10 minutes and recorded for 250 days between 24 October 2012 and 30 June 2013. Long-Term Spectral Averages (LTSAs) were created for three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations. Calls of blue whales, fin whales, minke whales, possible sei whales, Blainville’s beaked whales, Cuvier’s beaked whales, Gervais’ beaked whales, Kogia spp., Risso’s dolphins, sperm whales, and unidentified odontocetes and mysticetes were detected in the data.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between May 2014 and April 2015 in the Cape Hatteras, NC, survey area at Site A in 850 m. This HARP sampled continuously at 200 kHz and recorded for 217 days between 9 May 2014 and 11 December 2014. The data were divided into three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations using Long-Term Spectral Averages (LTSAs) and automated detectors. Vocalizations of blue whales, fin whales, minke whales, sei whales, North Atlantic right whales, humpback whales, Kogia spp., Risso’s dolphins, sperm whales, Cuvier’s beaked whales, Gervais’ beaked whales, Blainville’s beaked whales, and unidentified delphinids were detected in the data.

The U.S. Navy has been using High-frequency Acoustic Recording Packages (HARPs) to conduct passive acoustic monitoring in waters offshore of Virginia, North Carolina, and Florida to determine patterns of occurrence and distribution of cetacean species and anthropogenic sounds since 2007. Many baleen whale species and six known odontocete taxa (Kogia spp., Risso’s dolphins (Grampus griseus), sperm whales (Physeter macrocephalus), Cuvier’s beaked whale (Ziphius cavisrostris), Gervais’ beaked whale (Mesoplodon europaeus), and Blainville’s beaked whale (M. densirostris)) had previously been identified within these recordings; however, a much larger number of detections of unidentified odontocete clicks remained. This work looked at steps toward classification of these unidentified odontocete clicks.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between June 2014 and April 2015 in Norfolk Canyon, VA, at Site A in 982 m. This HARP sampled continuously at 200 kHz and recorded for 290 days between 19 June 2014 and 5 April 2015. The data were divided into three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations using Long-Term Spectral Averages (LTSAs) and automated detectors. Vocalizations of blue whales, fin whales, minke whales, sei whales, humpback whales, Kogia spp., Risso’s dolphins, sperm whales, Cuvier’s beaked whales, Gervais’ beaked whales, possible Sowerby’s beaked whales, and unidentified delphinids were detected in the data.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between May 2013 and March 2014 in the Cape Hatteras, NC, survey area at Site A in 970 m. This HARP sampled continuously at 200 kHz and recorded for 290 days between 29 May 2013 and 15 March 2014. The data were divided into three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations using Long-Term Spectral Averages (LTSAs) and automated detectors. Vocalizations of blue whales, fin whales, minke whales, sei whales, North Atlantic right whales, humpback whales, Kogia spp., Risso’s dolphins, sperm whales, Cuvier’s beaked whales, Gervais’ beaked whales, Blainville’s beaked whales, possible Sowerby’s beaked whales, and unidentified delphinids were detected in the data.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between October 2012 and May 2013 in the Cape Hatteras, NC, survey area at Site A in 970 m. This HARP sampled continuously at 200 kHz and recorded for 212 days between 9 October 2012 and 9 May 2013. The data were divided into three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned for marine mammal vocalizations using Long-Term Spectral Averages (LTSAs) and automated detectors. Vocalizations of blue whales, fin whales, minke whales, sei whales, North Atlantic right whales, humpback whales, Kogia spp., Risso’s dolphins, sperm whales, Cuvier’s beaked whales, Gervais’ beaked whales, Blainville’s beaked whales, and unidentified delphinids were detected in the data.

The U.S. Navy has been using High-frequency Acoustic Recording Packages (HARPs) to conduct passive acoustic monitoring in waters offshore of Virginia, North Carolina, and Florida to determine patterns of occurrence and distribution of cetacean species and anthropogenic sounds since 2007. The datasets discussed in this annual report came from seven HARP deployments made from 2012 through 2016: one near Norfolk Canyon, off the coast of Virginia (982 meter [m] depth) between June 2014 and April 2015; four off Cape Hatteras, North Carolina (850–980 m depths) between October 2012 and April 2016; and two off Jacksonville, Florida (800–806 m depths) between August 2014 and April 2016.

A High-frequency Acoustic Recording Package (HARP; Wiggins and Hildebrand 2007) was deployed between August 2014 and July 2015 in the Jacksonville, FL, survey area at Site D in 806 m. This HARP sampled continuously at 200 kHz and recorded for 279 days between 23 August 2014 and 29 May 2015. The data were divided into three frequency bands (10 Hz – 1000 Hz, 500 Hz – 5000 Hz, and 1 kHz – 100 kHz) and scanned manually for marine mammal vocalizations using Long-Term Spectral Averages (LTSAs) and automated computer algorithm detection when possible. Vocalizations of fin whales, minke whales, sei whales, Kogia spp., Risso’s dolphins, sperm whales, Blainville’s beaked whales, Gervais’ beaked whales, and unidentified delphinids were detected in the data.

This report forms part of a multi-institutional monitoring project intended to provide information on the species composition, population identity, density and baseline behavior of marine mammals and sea turtles present in Navy range complexes along the Atlantic coast. This program began in 2007, with baseline aerial and vessel surveys and a passive acoustic monitoring program in Onslow Bay, North Carolina and has since expanded to include study areas off Jacksonville, Florida and Cape Hatteras, North Carolina. In Onslow Bay, six years of monitoring have yielded a comprehensive picture of the density, distribution and abundance of marine mammals and sea turtles and provided new insights into residency patterns among pelagic delphinid cetaceans in this region. More than four years of monitoring in Jacksonville have provided similar information on the density and distribution of marine mammals and sea turtles in this area. In Cape Hatteras, almost three years of surveys have provided preliminary information on the complex patterns of distribution and diversity of the marine mammals and sea turtles in this highly productive area. The current report builds on this past body of work and describes passive acoustic monitoring activities that occurred at these three sites between January and December 2013.

In October 2005, the U.S. Department of the Navy proposed the installation of an Undersea Warfare Training Range (USWTR) in one of four sites along the Atlantic coast, for the purpose of anti-submarine warfare training using mid-frequency tactical sonar (1-10 kilohertz [kHz]) in shallow waters. The initial preferred site for the USWTR was Onslow Bay, North Carolina.

The primary objectives of the passive acoustic 26 monitoring program are to: 1) Determine the patterns of occurrence at each monitoring site; 2) Compare patterns of occurrence to better understand distributional patterns; and 3) Document species-specific characteristics of the vocalizations of marine mammal species 30 in each area.

This report forms part of a multi-institutional monitoring project intended to provide information on the species composition, population identity, density and baseline behavior of marine mammals and sea turtles present in Navy range complexes along the Atlantic coast. This program began in 2007, with baseline aerial and vessel surveys and a passive acoustic monitoring program in Onslow Bay, North Carolina and has since expanded to include study areas off Jacksonville, Florida and Cape Hatteras, North Carolina. In Onslow Bay, six years of monitoring have yielded a comprehensive picture of the density, distribution and abundance of marine mammals and sea turtles and provided new insights into residency patterns among pelagic delphinid cetaceans in this region. More than four years of monitoring in Jacksonville have provided similar information on the density and distribution of marine mammals and sea turtles in this area. In Cape Hatteras, almost three years of surveys have provided preliminary information on the complex patterns of distribution and diversity of the marine mammals and sea turtles in this highly productive area. The current report builds on this past body of work and describes monitoring activities that occurred between January and December 2013.

This report forms part of a multi-institutional monitoring project intended to provide information on the species composition, population identity, density and baseline behavior of marine mammals and sea turtles present in Navy range complexes along the Atlantic coast. This program began in 2007, with baseline aerial and vessel surveys and a passive acoustic monitoring program in Onslow Bay, North Carolina and has since expanded to include study areas off Jacksonville, Florida and Cape Hatteras, North Carolina

We have been conducting ongoing monthly aerial surveys off Cape Hatteras, NC, USA as part of the US Navy's marine species monitoring program in the Atlantic since 2011. We utilize line transect survey methods and extensively photograph all sightings to confirm species identification. Survey tracklines extend from shallow continental shelf waters, across the shelf break, to deep pelagic waters. From May 2011 through December 2014, 26,131km of trackline were flown, and 9,941 individual cetaceans were documented during 437 encounters. Nineteen species of cetaceans, including three mysticetes (Balaenoptera physalus, B. acutorostrata, Megaptera novaeangliae), five deep-divers (Physeter microcephalus, Kogia spp., Ziphius cavirostris, Mesoplodon europaeus, M. mirus), and eleven delphinids (Tursiops truncatus, Stenella frontalis, S. attenuate, S. coeruleoalba, S. clymene, S. longirostris, Steno bredanensis, Peponocephala electra, Lagenodelphis hosei, Grampus griseus and Globicephala macrorhynchus) were encountered. Similar surveys at the adjacent Onslow Bay, NC site yielded only 257 sightings (4,773 individuals representing nine species) despite nearly two times the survey effort flown (48,698km). At Cape Hatteras, minimum abundance estimates (i.e. uncorrected for availability or perception bias) were generated using spatio-temporal density surface modelling for species with sufficient detections. Predicted monthly abundance of T. truncatus varied between 170 (95% confidence interval; 0 - 17,100) and 3,450 (300 - 8,510). Monthly Stenella spp. abundance varied between 110 (0 - 360) and 1,720 (400 - 5,390). Monthly abundance of G. macrorhynchus varied between 10 (0 - 960) and 1,230 (220 - 4,300). These results demonstrate that the waters off Cape Hatteras support both higher diversity and density of cetaceans than adjacent waters along the US Atlantic coast. This site is included in the area of interest identified in six pending permits for large-scale, commercial seismic surveys. We suggest that the high density and diversity of cetaceans at this site warrants a special degree of concern by the US Bureau of Ocean Energy Management.

We conducted monthly aerial surveys off Cape Hatteras, NC, USA as part of an ongoing monitoring project of sites utilized by the US Navy for training and testing activities along the US Atlantic coast. Survey tracklines extend from shallow continental shelf waters, across the continental shelf break, to deep pelagic waters. During surveys we record the geographic position of each marine mammal sighting, take extensive photographs of each animal, and review these images in the lab to confirm species identification. Characteristics utilized to identify beaked whales to species are based upon our sightings of adult males with erupted teeth and from comparisons with images of stranded animals. Between May 2011 and December 2014, we recorded 63 beaked whale sightings, representing 173 individuals. Beaked whales were observed in every month of the year, with the highest number of sightings (n=42) from May through August. The most commonly encountered species, observed in every month of the year, was Ziphius cavirostris (n=36 sightings, 106 individuals). Mesoplodon spp. (n=27 sightings, 67 individuals) were encountered in all months except September and October. Five of these mesoplodont sightings could be identified to species with M. europaeus (n=4 sightings, 12 individuals) and M. mirus (n=1 sighting, 2 individuals) identified from May through July. All beaked whales were encountered along the continental shelf break suggesting a restricted distribution. This area has recently been opened by the US Bureau of Ocean Energy Management to offshore oil and gas exploration. The geographic distribution of beaked whales off Cape Hatteras overlaps the "Manteo Prospect" and is included in the areas of interest identified in six pending permits for large-scale, commercial seismic surveys. The cumulative impacts of seismic surveys are of special concern as deep-diving beaked whales have been shown to be vulnerable to high-amplitude, impulsive anthropogenic sounds.

Beaked whales are vulnerable to the impacts of disturbance from several sources of anthropogenic sound. Here we report the distribution and abundance of beaked whales off Cape Hatteras, North Carolina, U.S.A., an area utilized by the U.S. Navy for training exercises, and of particular interest for seismic geophysical surveys. From May 2011 through November 2015, monthly aerial surveys were conducted at the site. Beaked whales were encountered 74 times (n = 205 individuals) during these surveys. Ziphius cavirostris, the most commonly encountered species, was observed in every month of the year. Mesoplodon spp. were encountered in ten months of the year. Photographs of adult males with erupted teeth permitted six sightings to be identified conclusively as M. europaeus; M. mirus was also photographed just outside the study area. Beaked whale surface densities stratified by depth (0.005–0.007/km2) were among the highest reported in the world for small ziphiids. A quantitative comparison of sightings and stranding records suggests that strandings do not accurately reflect the relative abundance of beaked whale species in this area. We conclude that Cape Hatteras, at the convergence of the Labrador Current and Gulf Stream, is a particularly important year-round habitat for several species of beaked whales.

We conducted monthly aerial surveys off Cape Hatteras, NC, USA as part of an ongoing monitoring project of sites utilized by the US Navy for training and testing activities along the US Atlantic coast. Survey tracklines extend from shallow continental shelf waters, across the continental shelf break, to deep pelagic waters. During surveys we record the geographic position of each marine mammal sighting, take extensive photographs of each animal, and review these images in the lab to confirm species identification. Characteristics utilized to identify beaked whales to species are based upon our sightings of adult males with erupted teeth and from comparisons with images of stranded animals we have confirmed species ID.

From 2007 to2013,acomprehensive acoustic monitoring effort was conducted within the boundaries of the Onslow Bay study area to study marine mammal presence and ambient noise levels. The objective was to characterize the vocalizations of marine mammal species in the area, identify their seasonal presence patterns, and assess the potential impacts of naval operations on these species. This report presents the findings from the analysis of data collected using High-frequency Acoustic Recording Packages (HARPs; (Wiggins & Hildebrand 2007)), which were strategically deployed within the Onslow Bay study area across a shelf-to-slope gradient.

From 2012 to 2020, a comprehensive acoustic monitoring effort was conducted within the boundaries of the Virginia Capes Range Complex to study marine mammal presence and ambient noise levels. The objective was to characterize the vocalizations of marine mammal species in the area, identify their seasonal presence patterns, and assess the potential impacts of naval operations on these species. This report presents the findings from the analysis of data collected using 12 High-frequency Acoustic Recording Packages (HARPs; Wiggins & Hildebrand 2007), which were strategically deployed offshore from Cape Hatteras within the southern portion of the Virginia Capes Range Complex (Figure 1 & Table 1).

From 2014 to2021, a comprehensive acoustic monitoring effort was conducted within the boundaries of the Virginia Capes Range Complex to study marine mammal presence and ambient noise levels. The objective was to characterize the vocalizations of marine mammal species in the area, identify their seasonal presence patterns, and assess the potential impacts of naval operations on these species. This report presents the findings from the analysis of data collected using six High-frequency Acoustic Recording Packages (HARPs; Wiggins & Hildebrand 2007), which were strategically deployed within the Virginia Capes Range Complex near Norfolk Canyon (Figure 1 & Table 1).

Two High-Frequency Acoustic Recording Packages (HARP) were deployed sequentially from May 2017 to June 2018 to record marine mammal and anthropogenic sounds in the Navy’s Virginia Capes Range Complex offshore ~ 44 nm northeast from Cape Hatteras (HAT).

A High-Frequency Acoustic Recording Package (HARP) was deployed from April 2016 to June 2017 to detect marine mammal and anthropogenic sounds in the Navy’s Virginia Capes Range Complex offshore from Norfolk Canyon (NFC). The HARP was located 75 nm offshore in approximately 1000 m of water. The HARP recorded sound in the frequency band 10 Hz – 100 kHz. Data analysis consisted of analyst scans of long-term spectral averages (LTSAs) and spectrograms, and automated computer algorithm detection when possible. Three frequency bands were analyzed for marine mammal vocalizations and anthropogenic sounds: (1) Low-frequency, between 10-500 Hz, (2) Mid-frequency, between 10-5,000 Hz, and (3) High-frequency, between 1- 100 kHz.

Three High-Frequency Acoustic Recording Packages (HARPs) were deployed from June 2018 to September 2019 to detect marine mammal and anthropogenic sounds offshore in the Navy’s Virginia Capes Range Complex, approximately 44 nm northeast from Cape Hatteras (HAT).

A High-Frequency Acoustic Recording Package (HARP) was deployed from June 2018 to May 2019 to detect marine mammal and anthropogenic sounds in the Navy’s Virginia Capes Range Complex near Norfolk Canyon (NFC).

A High-Frequency Acoustic Recording Package (HARP) was deployed from June 2017 to June 2018 to detect marine mammal and anthropogenic sounds in the Navy’s Virginia Capes Range Complex offshore from Norfolk Canyon (NFC).

A High-Frequency Acoustic Recording Package (HARP) was deployed from April 2016 to February 2017 to detect marine mammal and anthropogenic sounds in the Navy’s Virginia Capes Range Complex offshore from Cape Hatteras (HAT). The HARP was located 75 nm offshore in approximately 1000 m of water. The HARP recorded sound in the frequency band 10 Hz – 100 kHz. Data analysis consisted of analyst scans of long-term spectral averages (LTSAs) and spectrograms, and automated computer algorithm detection when possible. Three frequency bands were analyzed for marine mammal vocalizations and anthropogenic sounds: (1) Low-frequency, between 10-500 Hz, (2) Mid-frequency, between 500-5,000 Hz, and (3) High-frequency, between 5- 100 kHz.

Three High-Frequency Acoustic Recording Packages (HARPs) were deployed from June 2018 to September 2019 to detect marine mammal and anthropogenic sounds offshore in the Navy’s Virginia Capes Range Complex, approximately 44 nm northeast from Cape Hatteras (HAT).

Beaked whales (family Ziphiidae) and sperm whales (Physeter macrocephalus) inhabit the continental shelf slope and pelagic waters in the western North Atlantic Ocean, but little is known about their associations with dynamic oceanographic features, such as fronts, which can aggregate prey. Here we analyze data from a multi-year passive acoustic monitoring program to explore associations between the foraging activity of beaked and sperm whales and the presence of the Gulf Stream, the dominant oceanographic feature off Cape Hatteras, North Carolina. From 2012 to 2015 we collected acoustic recordings on the continental slope using an autonomous, bottom-mounted acoustic recording package moored at approximately 900 m depth and sampling at 200 kHz.

Little is known about the ecology, habitat preferences, or seasonal distributions of beaked whale species (family Ziphiidae) in the western North Atlantic. Here we present an analysis of passive acoustic monitoring data which provides a multi-year record of beaked whale acoustic activity at two sites along the shelf break off North Carolina: Cape Hatteras (HAT) and Onslow Bay (OB).

This study investigated the effects of using duty-cycled passive acoustic recordings to monitor the daily presence of beaked whale species at three locations in the northwest Atlantic. Continuous acoustic records were subsampled to simulate duty cycles of 50%, 25%, and 10% and cycle period durations from 10 to 60 min. Short, frequent listening periods were most effective for assessing the daily presence of beaked whales. Furthermore, subsampling at low duty cycles led to consistently greater underestimation of Mesoplodon species than either Cuvier's beaked whales or northern bottlenose whales, leading to a potential bias in estimation of relative species occurrence.

Little is known about the ecology of many beaked whale species, despite concerns raised by mass strandings linked to certain sources of anthropogenic noise. Here, we used passive acoustic monitoring to examine spatial and temporal patterns in beaked whale occurrence at six locations along the continental slope in the western North Atlantic Ocean.

Long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break.

To better understand patterns in species distribution and vocal activity, NOAA’s Northeast Fisheries Science Center (NEFSC) and Scripps Institution of Oceanography (SIO) collaboratively deployed long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break. This work was conducted from 2015-2019, with financial support from the Bureau of Ocean Energy Management (BOEM). Likewise, the U.S. Navy has been monitoring the shelf break region at 3 to 4 sites since 2007. Together these combined efforts bring the total to 11 recording sites spanning the U.S. eastern seaboard, from New England to Florida. The work this year was aimed at finalizing components for these key objectives: I. Submit a manuscript describing the methodology of the beaked whale neural net classifier to be cited in future publications utilizing this approach II. Submit 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. III. Utilize passive acoustic data from ten shelf-break environments to evaluate composition and dissimilarity of marine mammal community groups at different latitudes.

Long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break.

Long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break.

Over 25 species of cetaceans utilize the shelf break regions of the US eastern seaboard, including several endangered species. Understanding patterns in species distribution, and the anthropogenic and environmental drivers that may impact their distribution, are critical for appropriate management of marine habitats. To better understand patterns in species distribution and vocal activity, NOAA’s Northeast Fisheries Science Center and Scripps Institution of Oceanography (SIO) collaboratively deployed long-term high-frequency acoustic recording packages (HARPs) at eight sites along the western North Atlantic shelf break. This work was conducted from 2015-2019, in coordination with the Bureau of Ocean Energy Management (BOEM). Likewise, the US Navy has been monitoring the shelf break region at 3 to 4 sites since 2007. Together these combined efforts bring the total to 11 recording sites spanning the U.S. eastern seaboard, from New England to Georgia.

A High-frequency Acoustic Recording Package (HARP) was deployed from July 2015 to April 2016, with recordings made between July 2015 and November 2015, to detect marine mammal and anthropogenic sounds in the Navy’s Jacksonville Range Complex. The HARP was located 83 nm off the Florida coastline on the continental slope.

During fieldwork supporting the Atlantic Behavioral Response Study (BRS) in 2023 (Southall et al. 2024) and other related research, more than 17,000 digital images were collected within the Cape Hatteras study area. These images were used to confirm species, identify individual animals, compile sighting histories, and conduct follow-up monitoring of satellite-tagged animals. Digital photographs were taken with Canon or Nikon digital single lens reflex cameras equipped with 100- to 400-millimeter zoom lenses in 24-bit color at a resolution of 6016 × 4016 pixels and saved in .jpg format. Photographs were obtained from five species, with most of them being Ziphius cavirostris, which will be referred to as ‘Ziphius’ or Zc, the primary focal species of BRS field efforts.

This study aims to assess the co-occurrence of cetaceans and anthropogenic activities, presenting simple and accessible visualizations of the temporal and spectral overlap.