37 Cetacean Weekly Acoustic Presence
Description: Passive acoustic monitoring (PAM) is a non-invasive method for studying cetaceans, relying on the detection of the unique vocalizations that cetaceans produce. PAM provides continuous sampling effort in areas that are otherwise difficult to access and provides information on multiple species simultaneously. The resulting long-term, robust datasets allow for insights into species distributions, behavior, and habitat use. Furthermore, PAM can be used from a management perspective to implement risk mitigation efforts, assess the cumulative impacts of stressors, and evaluate potential behavioral and distributional changes resulting from climate change or anthropogenic activity.
Indicator family:
Contributor(s): Renea Briner, Amanda Holdman, Daryll Carlson, Genevieve Davis, Rhett Finley, Sophie Ferguson, Leila Hatch, Katie Kowarski, Bruce Martin, Jessica McCordic, Jennifer Miksis-Olds, Hilary Moors-Murphy, Xavier Mouy, Anita Murray, Maricarmen Serna, Erin Summers, Joy Stanistreet, Lindsey Transue, Christopher Tremblay, Annabel Westell, Rebecca Vanhoeck, Emma Vergow, Sofie Van Parijs, Mark Baumgartner, Joel Bell, Amy Engelhaupt, Paige Hanson, Hana Koilpillai, Melinda Rekdahl, Howard Rosenbaum, Julianne Wilder
Affiliations: NEFSC
37.1 Introduction to Indicator
The first indicator examined the weekly acoustic presence of eight cetacean species (harbor porpoise and sperm, humpback, minke, North Atlantic right, sei, fin, and blue whales) and one cetacean family (delphinid spp.) in the Gulf of Maine. The indicator stems from data collected across four years (2019-2023) and thirty recording sites. This summary allows for an improved understanding of how frequently each of the species was acoustically active and whether they exhibited seasonal patterns in their activity within the region. This data serves as a baseline summary for a region experiencing unprecedented warming and environmental change. A full description is in preparation for publication.
The second indicator examined the weekly acoustic presence of six baleen whale species (North Atlantic right, sei, humpback, fin, blue, and minke whales) in the Mid-Atlantic Bight. The indicator stems from data collected across two years (2022-2024) and thirteen recording sites. This summary allows for an improved understanding of how frequently each of the species was acoustically active and whether they exhibited seasonal patterns in their activity within the region. This data serves as a baseline summary for a previously understudied region that has historically been viewed as a migratory corridor for baleen species. A full description is in preparation for publication.
37.2 Key Results and Visualizations
37.3 Indicator statistics
Spatial scale: A total of thirty PAM units were located throughout the Gulf of Maine spanning the coastal shelf, deep basins, and offshore banks. A total of thirteen PAM units were located throughout the US Mid-Atlantic Bight shelf area of the Northwestern Atlantic Ocean. The southernmost recorders were located off the mouth of the Chesapeake Bay and the northernmost recorders were located south of Long Island, NY. Recorders were arranged in transects spanning the continental shelf.
Temporal scale: In the Gulf of Maine, acoustic data were summarized from a four-year continuous sampling period spanning September 2019 to September 2023. In the Mid-Atlantic Bight, acoustic data were summarized from a two-year continuous sampling period spanning June 2022 to November 2024.
Synthesis Theme:
37.4 Implications
Acoustic summaries show that the Gulf of Maine and Mid-Atlantic Bight are important habitats for cetaceans, with many species detected year-round. Peak acoustic presence varied by species/family, with all groups exhibiting seasonal presence patterns. More fine-scale analyses reveal interannual and subregional differences in cetacean acoustic presence, highlighting the dynamic nature of the region.
Gulf of Maine
Continuous Presence: Harbor porpoises, delphinids, humpback whales, and fin whales were acoustically present most days of the week year-round, with a slight decrease in harbor porpoise and fin whale detections in the summer (May-July) and a slight decrease in humpback whale detections in the late-winter (February) and summer (June-August). Winter Presence: Blue whales were detected most weeks throughout the fall and winter (September-February).
Summer Absence: Sei whales were detected throughout the fall, winter, and spring, but had fewer days with detections in the summer (June-August). Sei whale acoustic presence particularly peaked in the spring (March-May) and fall (October-November). North Atlantic right whale acoustic presence followed similar trends to sei whale acoustic presence, with the least days with detections in the summer, and more days with detections throughout the fall, winter, and spring. However, right whales had fewer detections than sei whales throughout the fall and early-winter, and right whale acoustic presence peaked earlier in the spring (March) than sei whale acoustic presence.
Highly Variable: Minke whale acoustic presence greatly varied, but was generally consistent with some days each week detected throughout the spring, summer, and fall (March-November). Sperm whales were detected year-round, but were highly variable in the number of days with detections each week. Variability is likely driven by interannual and subregional differences, as this indicator covers multiple habitat types.
Mid-Atlantic Bight
Winter Presence: Humpback, North Atlantic right, and fin whales were all detected most weeks throughout the winter (November-February). Leading into and out of the winter months, fall and spring acoustic presence varied between the three species, with North Atlantic right whales having the shortest peak detection window (December-January). Blue whales were also acoustically present on a few occasions in the winter. Spring Presence: Sei whales showed a peak in detections in spring (April-May) with sporadic acoustic presence in other months.
Summer Presence: No species were consistently detected in summer months (June-July); however, humpback, minke, North Atlantic right, sei, and fin whales were all detected at least once.
Highly Variable: Minke whale acoustic presence greatly varied by site and year, but generally peaked in spring (March-April) and late summer into fall (August-October).
37.5 Get the data
Point of contact: Sofie Van Parijs (sofie.vanparijs@noaa.gov)
ecodata name: ecodata::cetacean_acoustic
Variable definitions
- Acoustic presence; Definition: At least 1 species-specific call was observed on a given day. For North Atlantic right whale acoustic presence is defined as 3 species-specific calls observed on a given day.
- Weekly acoustic presence: Definition: median number of days of acoustic presence per calendar week across all data at four recording sites
Indicator Category:
37.7 Accessibility and Constraints
No response
tech-doc link https://noaa-edab.github.io/tech-doc/cetacean_acoustic.html