Kerri D. Seger, Ph.D.

Songbird and Traffic Noise Study, Columbus, Ohio — Recorded northern cardinals and American robins in four soundscapes of varying urbanization around Columbus, Ohio, and found changes in frequencies in songs with increasing highway traffic noise as part of undergraduate honors thesis.

Gray Whale Breeding Lagoon Soundscape Parameterization, Laguna San Ignacio, México — Characterized soundscapes in three areas of a gray whale breeding lagoon, found they were significantly different, and coined the term “aural camouflage” for the assumption that masking sound from snapping shrimp in the Northern Zone provided gray whale mothers and calves an acoustical cloak to prevent being heard by male gray whales (meaning they could communicate at close ranges with less chance of eavesdropping).

Estimating Amount of Sound Introduced to a Soundscape from a Single Singing Humpback Whale, Los Cabos, México — Field-tested Dr. Aaron Thode’s idea that a single singing humpback whale would introduce an average amount of sound to the soundscape so that by measuring the sound pressure in the bandwidth of song, it could be estimated how many whales were singing in the detection range of a hydrophone. In the waters around Los Cabos, this worked, whereby each singing whale added ~0.67 dB to the bandwidth of interest.

Humpback Whale Social Call Cataloguing, México and Hawai‘i — Placed acoustic tags on humpback whales around Los Cabos, México, and Maui, Hawaii, to start the social call catalogue of the North Pacific humpback whale distinct population segment. This built on the social call catalogue started by Rebecca Dunlop in Australia and continues today as an international working group to build a global social call catalogue for the species.

Baseline Soundscape Long-Term Acoustics Data Set Collecting, Gulf of Tribugá, Colombia — Established the first passive acoustics monitoring project on the Pacific Coast of Colombia in collaboration with Fundación Macuáticos Colombia as part of Fulbright Scholar Award in 2018. Data have been collected every year, and monitoring of the soundscapes’ trends, humpback whales’ reactions to noise, fish presence, snapping shrimp acoustic intensities, and propagation modeling from local ship traffic continue to be published in student theses. So far, one intern, four undergraduates, and two master’s students have used these data for their projects.

Camera Tagging an Orca and Humpback Whale during a Hunt, Dominican Republic — While filming for a docuseries, OceanXplorers, placed two camera tags on the matriarch of a killer whale pod and the humpback whale calf that the pod eventually hunted and consumed. This verified that orcas in the Caribbean are a marine-mammal-eating ecotype and provided video and audio details about their hunting methods and how they butcher the prey underwater for group consumption. This paper is still in preparation.

Proof-of-Concept Measurement of Echoes in an Underwater “Amphitheater,” Dominican Republic — While filming for a docuseries, OceanXplorers, several amphitheaters were mapped into which humpback whales were observed singing. To test the echo intensity and directionality off that bowl-shaped inverted “amphitheater,” set out a floating 11-element array of surface hydrophones and deployed five bottom-mounted hydrophones (on a ledge at the back of the amphitheater), then played simulated humpback whale song units into the bowl shape to measure whether or not the echo from the “song” combined with the direct path of the “song” (to essentially amplify the voice of a singing humpback whale). These data are still being analyzed.

Combining Global Ocean Bottom Seismometers and CTBTO Recordings to Estimate Abundance and Density of Fin and Blue Whales (CORTADO), Wake Island and Diego Garcia — As part of a larger project with a University of St. Andrews, used CTBTO data from Wake Island and Diego Garcia to revise and prepare code (for posting on GitHub) that estimates the density of fin whales within the detection range of a hydrophone triad. Case study biological questions comparing fin whale densities across time and space are being used to ground-truth the functionality of the codebase. This project is set to be completed in June 2025.

Application of an EMD Detection and Classification Process to Environments for Naval Monitoring and Detection, Various Data Sets — Refined empirical and variational mode decomposition (EMD and VMD, respectively) algorithms from the wireless communication field to 1) filter out unwanted modes in acoustic data, and 2) sort/cluster signals semi-blindly by frequency content of a time series. Data sets spanned four types of hydrophone instruments, five sampling rates, and ecosystems in four oceans and one river for a total of 25 known signal types. Created various spectrographic depictions to better evaluate the success of the EMD and VMD algorithms. The most useful application was using VMD to separate clicks of Risso’s dolphins from Pacific white-sided dolphins (which have very similar peak and notch patterns in the ultrasonic range).

Monitoring for Shifts in Odontocete Range and Distribution in the Arctic and Subarctic Seas, Bering and Chukchi Seas — Used a decade of active and passive acoustic data from three moorings in the Bering and Chukchi seas to measure the presence of any classifiable odontocete signals. Used generalized additive models to relate the acoustic presence trends of commonly signaling species with environmental trends. Main discoveries included 1) detecting three species of odontocetes that should not have been so far north, and 2) documenting the strength of the effect of the ice edge on various species. During fieldwork, worked closely with the National Oceanic and Atmospheric Administration’s (NOAA’s) Northwest acoustics laboratory to search for North Pacific right whales with sonobuoys.

Chukchi Sea Environmental Studies Program, North Slope of Alaska, Bering and Chukchi Seas and Various Ports of Call — Participated in the deployment and recovery of directional autonomous seafloor acoustic recorders (DASARs) for monitoring soundscapes of five regions along the North Slope. Processed sound pressure data from these sensors to report on soundscape metrics across all five regional DASAR stations. Manually analyzed and trained analysts to annotate bowhead whale calls for training a detector and for developing a method to measure the depth of a calling bowhead whale.

Parametric Analysis and Sensitivity Study of the Acoustic Propagation for Renewable Energy, Coasts of Rhode Island and Virginia — Made propagation models using parabolic equation of piles being driven at several places in all four seasons under various bottom sediment grain sizes in areas proposed for leases off the coasts of Rhode Island and Virginia. Estimated the volume of water around a pile that would exceed the permanent threshold shift (PTS), temporary threshold shift (TTS), and behavioral thresholds of all hearing groups and evaluated the variability in these volumes depending on seasonal, sediment, and distance-from-shore characteristics. The results were compiled as the damped cylindrical spreading in Excel^TM (DCSiE) spreadsheet intended to aid the Bureau of Ocean Energy Management (BOEM) and NOAA in permitting offshore wind farms. Project funded by BOEM.

Propagation Characteristics of High-Frequency Sounds Emitted during High-Resolution Geophysical Surveys: Acoustic Modeling Effort, Leesburg Acoustic Test Facility and Woods Hole Oceanographic Institution Marine Operations Center, Massachusetts — Funded by BOEM, led a project that took recordings of 41 versions of 18 distinct, calibrated geophysical survey systems from a bottom-mounted array of hydrophones and adjusted the propagation models for each nonpoint source version using the actual data. Developed a web-based lookup tool for users to understand the area around each version that would exceed PTS, TTS, and behavioral thresholds for several marine fauna hearing groups.

Collection of In Situ Acoustic Data for the Validation of U.S. Navy Propagation Models of Ship Shock Trial Sound Sources, Offshore Jacksonville, Florida — Planned, collected, and analyzed acoustic data from the explosions of ~40,000 lb of TNT as used during the full ship shock trials of the USS Gerald R. Ford. Data were given to the Naval Undersea Warfare Center to test their Navy Acoustic Effects MOdel (NAEMO) propagation model. Propagation models were used to estimate the volume of water ensonified above PTS, TTS, and behavioral thresholds for the low-frequency marine mammal hearing group. Data were analyzed in a before-after control-impact (BACI) framework to evaluate presence of behavioral calling changes from all classifiable species because of the explosions. Data are now open access through the Institute of Electrical and Electronics Engineers (IEEE).

Aquatic Ecology Laboratory Projects, Ohio and Louisiana — Assisted professors and graduate students in laboratory work like separating larvae from soil samples and classifying them to species. Assisted graduate students in stream ecology and watershed fieldwork. Used electrofishing, D-netting, seining, YSI meters, and geospatial measurements to collect data to evaluate stream health in various ecosystems and farming areas.

Monitoring for Shifts in Odontocete Range and Distribution in the Arctic and Subarctic Seas, Bering and Chukchi Seas — Used a decade of active and passive acoustic data from three moorings in the Bering and Chukchi seas to measure the presence of any classifiable odontocete signals. Used generalized additive models to relate the acoustic presence trends of commonly signaling species with environmental trends. Main discoveries included 1) detecting three species of odontocetes that should not have been so far north, and 2) documenting the strength of the effect of the ice edge on various species. During fieldwork, worked closely with the National Oceanic and Atmospheric Administration’s (NOAA’s) Northwest acoustics laboratory to search for North Pacific right whales with sonobuoys.

Parametric Analysis and Sensitivity Study of the Acoustic Propagation for Renewable Energy, Coasts of Rhode Island and Virginia — Made propagation models using parabolic equation of piles being driven at several places in all four seasons under various bottom sediment grain sizes in areas proposed for leases off the coasts of Rhode Island and Virginia. Estimated the volume of water around a pile that would exceed the permanent threshold shift (PTS), temporary threshold shift (TTS), and behavioral thresholds of all hearing groups and evaluated the variability in these volumes depending on seasonal, sediment, and distance-from-shore characteristics. The results were compiled as the damped cylindrical spreading in Excel^TM (DCSiE) spreadsheet intended to aid the Bureau of Ocean Energy Management (BOEM) and NOAA in permitting offshore wind farms. Project funded by BOEM.

Propagation Characteristics of High-Frequency Sounds Emitted during High-Resolution Geophysical Surveys: Acoustic Modeling Effort, Leesburg Acoustic Test Facility and Woods Hole Oceanographic Institution Marine Operations Center, Massachusetts — Funded by BOEM, led a project that took recordings of 41 versions of 18 distinct, calibrated geophysical survey systems from a bottom-mounted array of hydrophones and adjusted the propagation models for each nonpoint source version using the actual data. Developed a web-based lookup tool for users to understand the area around each version that would exceed PTS, TTS, and behavioral thresholds for several marine fauna hearing groups.

Collection of In Situ Acoustic Data for the Validation of U.S. Navy Propagation Models of Ship Shock Trial Sound Sources, Offshore Jacksonville, Florida — Planned, collected, and analyzed acoustic data from the explosions of ~40,000 lb of TNT as used during the full ship shock trials of the USS Gerald R. Ford. Data were given to the Naval Undersea Warfare Center to test their Navy Acoustic Effects MOdel (NAEMO) propagation model. Propagation models were used to estimate the volume of water ensonified above PTS, TTS, and behavioral thresholds for the low-frequency marine mammal hearing group. Data were analyzed in a before-after control-impact (BACI) framework to evaluate presence of behavioral calling changes from all classifiable species because of the explosions. Data are now open access through the Institute of Electrical and Electronics Engineers (IEEE).

Aquatic Ecology Laboratory Projects, Ohio and Louisiana — Assisted professors and graduate students in laboratory work like separating larvae from soil samples and classifying them to species. Assisted graduate students in stream ecology and watershed fieldwork. Used electrofishing, D-netting, seining, YSI meters, and geospatial measurements to collect data to evaluate stream health in various ecosystems and farming areas.