Dimitri Ponirakis | Cornell University (original) (raw)
Papers by Dimitri Ponirakis
Frontiers in Marine Science, Aug 8, 2018
Journal of Mammalogy
Describing spatial and temporal occurrence patterns of wild animal populations is important for u... more Describing spatial and temporal occurrence patterns of wild animal populations is important for understanding their evolutionary trajectories, population connectivity, and ecological niche specialization, with relevance for effective management. Throughout the world, blue whales produce stereotyped songs that enable identification of separate acoustic populations. We harnessed continuous acoustic recordings from five hydrophones deployed in the South Taranaki Bight (STB) region of Aotearoa New Zealand from January 2016 to February 2018. We examined hourly presence of songs from three different blue whale populations to investigate their contrasting ecological use of New Zealand waters. The New Zealand song was detected year-round with a seasonal cycle in intensity (peak February–July), demonstrating the importance of the region to the New Zealand population as both a foraging ground and potential breeding area. The Antarctic song was present in two distinct peaks each year (June–Jul...
Endangered Species Research
As development of offshore wind energy areas (WEAs) progresses along the US Atlantic coast, so wi... more As development of offshore wind energy areas (WEAs) progresses along the US Atlantic coast, so will the spatiotemporal overlap and potential space-use conflict with vulnerable or protected wildlife, including Critically Endangered North Atlantic right whales (NARWs). Assessments of potential impacts from construction and operational activities on NARWs are dependent on the spatial, temporal, and acoustic overlaps between those activities and the occurrence of NARWs. Additionally, baseline distribution data of NARWs and data-driven policies are crucial to guide management decisions that minimize risk. The Massachusetts (MA) and Rhode Island-Massachusetts (RI-MA) Offshore WEAs currently comprise some of the largest lease areas and the first industry-scale offshore WEAs in the USA. Continuous passive acoustic data from 2011 through 2015 reveal highly variable seasonal, diel, and spatial NARW occurrence patterns within and near the MA and RI-MA WEAs. Under low (5th percentile) and media...
Global Oceans 2020: Singapore – U.S. Gulf Coast
This paper describes a compact and extensible marine autonomous passive acoustics recording syste... more This paper describes a compact and extensible marine autonomous passive acoustics recording system, called ROCKHOPPER. The low-noise recorder features a depth rating of 3,500 m and is capable of continuously collecting high-frequency (197 kHz, 24 bits) acoustic data for up to seven months. Because of its small form factor, the ROCKHOPPER can be deployed and recovered by a single person from small vessels, including rigid-hulled inflatable boats (RHIBs). The performance of the instrument was comprehensively evaluated during an offshore deployment in U.S. waters of the northern Gulf of Mexico. Specifically, the analysis encompassed acoustic data collected with five ROCKHOPPER units between May and November 2019. During this period, tropical storm Barry moved through the deployment area, which provided a unique opportunity to study the impacts of a tropical cyclone on the underwater soundscape.
Frontiers in Marine Science, 2021
The global COVID-19 pandemic caused a sharp decline in vessel traffic in many areas around the wo... more The global COVID-19 pandemic caused a sharp decline in vessel traffic in many areas around the world, including vessel-based tourism throughout Alaska, USA in 2020. Marine vessel traffic has long been known to affect the underwater acoustic environment with direct and indirect effects on marine ecological processes. Glacier Bay National Park in southeastern Alaska has monitored underwater sound since 2000. We used continuous, calibrated hydrophone recordings to examine 2020 ambient sound levels compared with previous years: 2018, the most recent year with data available, and 2016 for historical perspective. Park tourism occurs mainly in May–September. Overall, the number of vessel entries in Glacier Bay was 44–49% lower in 2020 (2020: n = 1,831; 2018: n = 3,599; 2016: n = 3,212) affecting all vessel classes, including the complete absence of cruise ships and only three tour vessel trips. In all years, we found clear seasonal and diurnal patterns in vessel generated noise, focused fr...
Animal Conservation, 2013
ABSTRACT Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For mari... more ABSTRACT Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For marine species that rely on acoustic cues to navigate, find food or select mates, sound is a key element of their environment. Chronic forms of human-generated ocean noise have the potential to mask communication signals over substantial fractions of their functional areas for substantial fractions of the year, which makes acoustic masking a qualitatively similar stressor to habitat loss. International policy decisions on chronic ocean noise are evolving, which creates an opportunity to advance the scientific foundation of decision-making. We measured ocean noise levels at 12 sites, chosen for current and predicted intensities of anthropogenic activities and importance to three endangered whale species in Canada's Pacific Ocean: fin, humpback and killer whales. Canada includes sound as a key element of resident killer whale critical habitat, but not for other species. In the frequency bands that killer whales use for social communication, noise levels were highest in legally designated killer whale critical habitats. In contrast, noise levels were generally lower in habitats known to be important for baleen whales, but these quieter areas are not yet given special legal protection. These noise levels translate into potentially serious fractions of lost opportunities for acoustic communication. Median noise levels are high enough to reduce the communication spaces for fin, humpback and killer whales under typical (median) conditions by 1, 52 and 62%, respectively, and 30, 94 and 97% under noisy conditions. As countries begin to articulate their policies to protect acoustic attributes of marine habitats under their jurisdiction, we recommend quantifying loss of communication space, but quantitative targets need to be set. We see two ways forward. Managers could specify limits of acceptable change in terms of population-level impacts, which can be modelled through effects from communication masking and/or disturbance on prey intake. Alternatively, managers can specify targets reflecting amount of habitat to protect for each species, adjusting upward to account for habitat effectively lost from chronic ocean noise.
Frontiers in Marine Science, 2021
Making Ambient Noise Trends Accessible (MANTA) software is a tool for the community to enable com... more Making Ambient Noise Trends Accessible (MANTA) software is a tool for the community to enable comparisons between soundscapes and identification of ambient ocean sound trends required by ocean stakeholders. MANTA enhances the value of individual datasets by assisting users in creating thorough calibration metadata and internationally recommended products comparable over time and space to ultimately assess ocean sound at any desired scale up to a global level. The software package combines of two applications: MANTA Metadata App, which allows users to specify information about their recordings, and MANTA Data Mining App, which applies that information to acoustic recordings to produce consistently processed, calibrated time series products of sound pressure levels in hybrid millidecade bands. The main outputs of MANTA are daily.csv and NetCDF files containing 60-s spectral energy calculations in hybrid millidecade bands and daily statistics images. MANTA data product size and formats...
The Journal of the Acoustical Society of America, 2006
ABSTRACT The North Atlantic right whale is a highly endangered species of baleen whale. Acoustic ... more ABSTRACT The North Atlantic right whale is a highly endangered species of baleen whale. Acoustic communication plays an important role in the social behavior of these whales. Right whales are found in coastal waters along the east coast of the United States, an area characterized by high levels of human activity. Most of these activities generatenoise that is propagated into the coastal marine environment. The goals of this project are to characterize the noise, both natural and anthropogenic, in right whale habitat areas to determine what levels of noise the whales are regularly exposed to, and whether the acoustic behavior of right whales changes in response to increased noise. Continuous recordings were made from autonomous bottom‐mounted recorders in three major habitat areas in 2004 and 2005; Cape Cod Bay (December–May), Great South Channel (May), and the Bay of Fundy, Canada (August) to passively detect right whales by recording their vocalizations. Here, we describe the ambient noise levels in these recordings to describe the daily acoustic environment of right whales, how noise varied over diel, weekly, and seasonal time scales, and whether noise levels correlated with any observed changes in acoustic behavior of the whales.
ArXiv, 2016
This work presents a new toolkit for describing the acoustic properties of the ocean environment ... more This work presents a new toolkit for describing the acoustic properties of the ocean environment before, during and after a sound event caused by an underwater seismic air-gun. The toolkit uses existing sound measures, but uniquely applies these to capture the early time period (actual pulse) and late time period (reverberation and multiple arrivals). In total, 183 features are produced for each air-gun sound. This toolkit was utilized on data retrieved from a field deployment encompassing five marine autonomous recording units during a 46-day seismic air-gun survey in Baffin Bay, Greenland. Using this toolkit, a total of 147 million data points were identified from the Greenland deployment recordings. The feasibility of extracting a large number of features was then evaluated using two separate methods: a serial computer and a high performance system. Results indicate that data extraction performance took an estimated 216 hours for the serial system, and 18 hours for the high perfo...
Scientific Reports
Understanding relationships between physical drivers and biological response is central to advanc... more Understanding relationships between physical drivers and biological response is central to advancing ecological knowledge. Wind is the physical forcing mechanism in coastal upwelling systems, however lags between wind input and biological responses are seldom quantified for marine predators. Lags were examined between wind at an upwelling source, decreased temperatures along the upwelling plume’s trajectory, and blue whale occurrence in New Zealand’s South Taranaki Bight region (STB). Wind speed and sea surface temperature (SST) were extracted for austral spring–summer months between 2009 and 2019. A hydrophone recorded blue whale vocalizations October 2016-March 2017. Timeseries cross-correlation analyses were conducted between wind speed, SST at different locations along the upwelling plume, and blue whale downswept vocalizations (D calls). Results document increasing lag times (0–2 weeks) between wind speed and SST consistent with the spatial progression of upwelling, culminating...
![Research paper thumbnail of Erratum: Hybrid millidecade spectra: A practical format for exchange of long-term ambient sound data [JASA Express Lett. 1(1), 011203 (2021)]](https://attachments.academia-assets.com/81886860/thumbnails/1.jpg)
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Endangered Species Research
Little is known about the winter distribution of the Critically Endangered eastern population of ... more Little is known about the winter distribution of the Critically Endangered eastern population of North Pacific right whale Eubalaena japonica (NPRW), but it has been proposed that the eastern Aleutian Islands, specifically Unimak Pass, constitute a plausible migratory route for individuals. This is a major point of concern given the high shipping traffic in this pass. Therefore, a long-term acoustic recorder was deployed in Unimak Pass (2009−2015), and NPRWs were identified using the 'up' and 'gunshot' call types during manual review of data (8188 recorded hours). Calls were grouped into periods of hypothesized migration (Dec−Feb and Mar−May) and other (Jun−Aug and Sep−Nov). Overall, NPRW calling was intermittent and clustered in time, suggestive of a few individuals transiting the area across seasons. Upcalls (n = 31) were detected on 7 d and occurred most often during Dec−Feb, whereas gunshots (n = 465) were detected on 32 d, occurring in all months except February and October. The majority of individual gunshot calls (n = 306) occurred over 3 d in Dec−Feb 2014−15. Because of this pattern, gunshot calling occurred on more days during Jun−Aug, while more individual calls occurred during Dec−Feb. Diel and seasonal trends in hourly call detection rates were absent. Together, these data confirm that NPRW use Unimak Pass both during and outside of the assumed migratory period. Pervasive vessel noise throughout the study highlights near constant potential for interaction with anthropogenic disturbance. Consistently higher vessel noise during Dec−Feb suggests that this species is most vulnerable during the assumed migratory period.
Endangered Species Research
Anthropogenic noise negatively impacts many species. One of the more insidious effects of elevate... more Anthropogenic noise negatively impacts many species. One of the more insidious effects of elevated noise levels is the reduction in area over which animals are able to acoustically communicate, often termed communication masking. This study utilizes modeling approaches to evaluate relative levels of masking for 4 baleen whale species from the combination of current ambient noise conditions and noise from discrete vessels operating in the Stellwagen Bank National Marine Sanctuary. Acoustic data were collected using bottom-mounted autonomous recorders. One day was analyzed for each of 5 different species-specific sound types, corresponding to peaks in occurrence of fin and humpback whale songs, humpback whale social sounds, minke whale pulse trains and North Atlantic right whale gunshots. Source levels for animals and 3 categories of vessels were calculated empirically; sound propagation was modeled using Bellhop ray tracing. An agent-based modeling framework was used to calculate changes in communication space (CS) in comparison to reference conditions (10 dB lower than current ambient noise). In these singleday snapshots, current ambient noise and noise from vessels for which automatic identification system (AIS) data were available contribute most heavily to loss of CS, followed by whale-watching and fishing vessels. Right whale gunshots experience the least amount of masking, while fin, humpback and minke whale signals experience masking levels of 80% or more. While these results incorporate several simplifying assumptions, this study further develops the framework by which to comparatively quantify masking, providing information on the relative degree of masking experienced between species and allowing for important insights on the relative contributions of different anthropogenic sound sources.
JASA Express Letters
This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, pas... more This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution. The format is a hybrid that uses 1 Hz resolution up to 455 Hz and millidecade frequency bands above 455 Hz. This hybrid is appropriate for many types of soundscape analysis, including detecting different types of soundscapes and regulatory applications like computing weighted sound exposure levels. Hybrid millidecade files are compressed compared to the 1 Hz equivalent such that one research center could feasibly store data from hundreds of projects for sharing among researchers globally. V
Endangered Species Research, 2016
The Gulf of Mexico ecosystem represents the intersection between high marine biodiversity and ext... more The Gulf of Mexico ecosystem represents the intersection between high marine biodiversity and extensive human use and impact. Anthropogenic marine activities are prominent in the Gulf, prompting concern regarding impacts of chronic elevated noise throughout the marine ecosystem. Since sound is a critical component of the marine environment and many marine animals in the Gulf utilize sound in different aspects of their life history, their basic ecology may be negatively affected by elevated anthropogenic noise. While there are data gaps regarding the impacts of noise on marine organisms, it is crucial to understand current ambient noise conditions to evaluate the implications of noise for the Gulf ecosystem. Ambient noise measurements provide a mechanism by which to sample the cumulative acoustic activity of an ecosystem, and holistically evaluate biotic, environmental, and human-induced acoustic contributions to the overall environment. In this study, acoustic data were collected at 7 sites in the northeastern Gulf of Mexico between July 2010 and February 2012. Ambient noise is presented in 3 frequency bands (low frequency [10-500 Hz], mid-frequency [500-1000 Hz], and high frequency [1000-3150 Hz]), with median sound levels of 112, 90, and 93 dB (re 1 μPa), respectively. Abiotic and anthropogenic noise sources significantly contributed to the ambient noise environment; however, seismic survey noise dominated the noise environment and chronically elevated noise levels across several paramount marine habitats. This study describes current noise conditions across the Gulf of Mexico with an intent to inform noise management strategies and investigate the potential ecological implications of elevated ambient noise.
Progress in Oceanography, 2015
OCEANS …, 2011
The possible effects of anthropogenic noise on the marine environment is becoming an important to... more The possible effects of anthropogenic noise on the marine environment is becoming an important topic in the oceanic community. The exploration for fossil-fuel or alternative energy and the construction of facilities to support these endeavors often ...
Advances in Experimental Medicine and Biology, 2016
In September and October 2011, a seismic survey took place in Baffin Bay, Western Greenland, in c... more In September and October 2011, a seismic survey took place in Baffin Bay, Western Greenland, in close proximity to a marine protected area (MPA). As part of the mitigation effort, five bottom-mounted marine acoustic recording units (MARUs) collected data that were used for the purpose of measuring temporal and spectral features from each impulsive event, providing a high-resolution record of seismic reverberation persistent after the direct impulse. Results were compared with ambient-noise levels as computed after the seismic survey to evidence that as a consequence of a series of repeating seismic impulses, sustained elevated levels create the potential for masking.
Frontiers in Marine Science, Aug 8, 2018
Journal of Mammalogy
Describing spatial and temporal occurrence patterns of wild animal populations is important for u... more Describing spatial and temporal occurrence patterns of wild animal populations is important for understanding their evolutionary trajectories, population connectivity, and ecological niche specialization, with relevance for effective management. Throughout the world, blue whales produce stereotyped songs that enable identification of separate acoustic populations. We harnessed continuous acoustic recordings from five hydrophones deployed in the South Taranaki Bight (STB) region of Aotearoa New Zealand from January 2016 to February 2018. We examined hourly presence of songs from three different blue whale populations to investigate their contrasting ecological use of New Zealand waters. The New Zealand song was detected year-round with a seasonal cycle in intensity (peak February–July), demonstrating the importance of the region to the New Zealand population as both a foraging ground and potential breeding area. The Antarctic song was present in two distinct peaks each year (June–Jul...
Endangered Species Research
As development of offshore wind energy areas (WEAs) progresses along the US Atlantic coast, so wi... more As development of offshore wind energy areas (WEAs) progresses along the US Atlantic coast, so will the spatiotemporal overlap and potential space-use conflict with vulnerable or protected wildlife, including Critically Endangered North Atlantic right whales (NARWs). Assessments of potential impacts from construction and operational activities on NARWs are dependent on the spatial, temporal, and acoustic overlaps between those activities and the occurrence of NARWs. Additionally, baseline distribution data of NARWs and data-driven policies are crucial to guide management decisions that minimize risk. The Massachusetts (MA) and Rhode Island-Massachusetts (RI-MA) Offshore WEAs currently comprise some of the largest lease areas and the first industry-scale offshore WEAs in the USA. Continuous passive acoustic data from 2011 through 2015 reveal highly variable seasonal, diel, and spatial NARW occurrence patterns within and near the MA and RI-MA WEAs. Under low (5th percentile) and media...
Global Oceans 2020: Singapore – U.S. Gulf Coast
This paper describes a compact and extensible marine autonomous passive acoustics recording syste... more This paper describes a compact and extensible marine autonomous passive acoustics recording system, called ROCKHOPPER. The low-noise recorder features a depth rating of 3,500 m and is capable of continuously collecting high-frequency (197 kHz, 24 bits) acoustic data for up to seven months. Because of its small form factor, the ROCKHOPPER can be deployed and recovered by a single person from small vessels, including rigid-hulled inflatable boats (RHIBs). The performance of the instrument was comprehensively evaluated during an offshore deployment in U.S. waters of the northern Gulf of Mexico. Specifically, the analysis encompassed acoustic data collected with five ROCKHOPPER units between May and November 2019. During this period, tropical storm Barry moved through the deployment area, which provided a unique opportunity to study the impacts of a tropical cyclone on the underwater soundscape.
Frontiers in Marine Science, 2021
The global COVID-19 pandemic caused a sharp decline in vessel traffic in many areas around the wo... more The global COVID-19 pandemic caused a sharp decline in vessel traffic in many areas around the world, including vessel-based tourism throughout Alaska, USA in 2020. Marine vessel traffic has long been known to affect the underwater acoustic environment with direct and indirect effects on marine ecological processes. Glacier Bay National Park in southeastern Alaska has monitored underwater sound since 2000. We used continuous, calibrated hydrophone recordings to examine 2020 ambient sound levels compared with previous years: 2018, the most recent year with data available, and 2016 for historical perspective. Park tourism occurs mainly in May–September. Overall, the number of vessel entries in Glacier Bay was 44–49% lower in 2020 (2020: n = 1,831; 2018: n = 3,599; 2016: n = 3,212) affecting all vessel classes, including the complete absence of cruise ships and only three tour vessel trips. In all years, we found clear seasonal and diurnal patterns in vessel generated noise, focused fr...
Animal Conservation, 2013
ABSTRACT Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For mari... more ABSTRACT Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For marine species that rely on acoustic cues to navigate, find food or select mates, sound is a key element of their environment. Chronic forms of human-generated ocean noise have the potential to mask communication signals over substantial fractions of their functional areas for substantial fractions of the year, which makes acoustic masking a qualitatively similar stressor to habitat loss. International policy decisions on chronic ocean noise are evolving, which creates an opportunity to advance the scientific foundation of decision-making. We measured ocean noise levels at 12 sites, chosen for current and predicted intensities of anthropogenic activities and importance to three endangered whale species in Canada's Pacific Ocean: fin, humpback and killer whales. Canada includes sound as a key element of resident killer whale critical habitat, but not for other species. In the frequency bands that killer whales use for social communication, noise levels were highest in legally designated killer whale critical habitats. In contrast, noise levels were generally lower in habitats known to be important for baleen whales, but these quieter areas are not yet given special legal protection. These noise levels translate into potentially serious fractions of lost opportunities for acoustic communication. Median noise levels are high enough to reduce the communication spaces for fin, humpback and killer whales under typical (median) conditions by 1, 52 and 62%, respectively, and 30, 94 and 97% under noisy conditions. As countries begin to articulate their policies to protect acoustic attributes of marine habitats under their jurisdiction, we recommend quantifying loss of communication space, but quantitative targets need to be set. We see two ways forward. Managers could specify limits of acceptable change in terms of population-level impacts, which can be modelled through effects from communication masking and/or disturbance on prey intake. Alternatively, managers can specify targets reflecting amount of habitat to protect for each species, adjusting upward to account for habitat effectively lost from chronic ocean noise.
Frontiers in Marine Science, 2021
Making Ambient Noise Trends Accessible (MANTA) software is a tool for the community to enable com... more Making Ambient Noise Trends Accessible (MANTA) software is a tool for the community to enable comparisons between soundscapes and identification of ambient ocean sound trends required by ocean stakeholders. MANTA enhances the value of individual datasets by assisting users in creating thorough calibration metadata and internationally recommended products comparable over time and space to ultimately assess ocean sound at any desired scale up to a global level. The software package combines of two applications: MANTA Metadata App, which allows users to specify information about their recordings, and MANTA Data Mining App, which applies that information to acoustic recordings to produce consistently processed, calibrated time series products of sound pressure levels in hybrid millidecade bands. The main outputs of MANTA are daily.csv and NetCDF files containing 60-s spectral energy calculations in hybrid millidecade bands and daily statistics images. MANTA data product size and formats...
The Journal of the Acoustical Society of America, 2006
ABSTRACT The North Atlantic right whale is a highly endangered species of baleen whale. Acoustic ... more ABSTRACT The North Atlantic right whale is a highly endangered species of baleen whale. Acoustic communication plays an important role in the social behavior of these whales. Right whales are found in coastal waters along the east coast of the United States, an area characterized by high levels of human activity. Most of these activities generatenoise that is propagated into the coastal marine environment. The goals of this project are to characterize the noise, both natural and anthropogenic, in right whale habitat areas to determine what levels of noise the whales are regularly exposed to, and whether the acoustic behavior of right whales changes in response to increased noise. Continuous recordings were made from autonomous bottom‐mounted recorders in three major habitat areas in 2004 and 2005; Cape Cod Bay (December–May), Great South Channel (May), and the Bay of Fundy, Canada (August) to passively detect right whales by recording their vocalizations. Here, we describe the ambient noise levels in these recordings to describe the daily acoustic environment of right whales, how noise varied over diel, weekly, and seasonal time scales, and whether noise levels correlated with any observed changes in acoustic behavior of the whales.
ArXiv, 2016
This work presents a new toolkit for describing the acoustic properties of the ocean environment ... more This work presents a new toolkit for describing the acoustic properties of the ocean environment before, during and after a sound event caused by an underwater seismic air-gun. The toolkit uses existing sound measures, but uniquely applies these to capture the early time period (actual pulse) and late time period (reverberation and multiple arrivals). In total, 183 features are produced for each air-gun sound. This toolkit was utilized on data retrieved from a field deployment encompassing five marine autonomous recording units during a 46-day seismic air-gun survey in Baffin Bay, Greenland. Using this toolkit, a total of 147 million data points were identified from the Greenland deployment recordings. The feasibility of extracting a large number of features was then evaluated using two separate methods: a serial computer and a high performance system. Results indicate that data extraction performance took an estimated 216 hours for the serial system, and 18 hours for the high perfo...
Scientific Reports
Understanding relationships between physical drivers and biological response is central to advanc... more Understanding relationships between physical drivers and biological response is central to advancing ecological knowledge. Wind is the physical forcing mechanism in coastal upwelling systems, however lags between wind input and biological responses are seldom quantified for marine predators. Lags were examined between wind at an upwelling source, decreased temperatures along the upwelling plume’s trajectory, and blue whale occurrence in New Zealand’s South Taranaki Bight region (STB). Wind speed and sea surface temperature (SST) were extracted for austral spring–summer months between 2009 and 2019. A hydrophone recorded blue whale vocalizations October 2016-March 2017. Timeseries cross-correlation analyses were conducted between wind speed, SST at different locations along the upwelling plume, and blue whale downswept vocalizations (D calls). Results document increasing lag times (0–2 weeks) between wind speed and SST consistent with the spatial progression of upwelling, culminating...
Endangered Species Research
Little is known about the winter distribution of the Critically Endangered eastern population of ... more Little is known about the winter distribution of the Critically Endangered eastern population of North Pacific right whale Eubalaena japonica (NPRW), but it has been proposed that the eastern Aleutian Islands, specifically Unimak Pass, constitute a plausible migratory route for individuals. This is a major point of concern given the high shipping traffic in this pass. Therefore, a long-term acoustic recorder was deployed in Unimak Pass (2009−2015), and NPRWs were identified using the 'up' and 'gunshot' call types during manual review of data (8188 recorded hours). Calls were grouped into periods of hypothesized migration (Dec−Feb and Mar−May) and other (Jun−Aug and Sep−Nov). Overall, NPRW calling was intermittent and clustered in time, suggestive of a few individuals transiting the area across seasons. Upcalls (n = 31) were detected on 7 d and occurred most often during Dec−Feb, whereas gunshots (n = 465) were detected on 32 d, occurring in all months except February and October. The majority of individual gunshot calls (n = 306) occurred over 3 d in Dec−Feb 2014−15. Because of this pattern, gunshot calling occurred on more days during Jun−Aug, while more individual calls occurred during Dec−Feb. Diel and seasonal trends in hourly call detection rates were absent. Together, these data confirm that NPRW use Unimak Pass both during and outside of the assumed migratory period. Pervasive vessel noise throughout the study highlights near constant potential for interaction with anthropogenic disturbance. Consistently higher vessel noise during Dec−Feb suggests that this species is most vulnerable during the assumed migratory period.
Endangered Species Research
Anthropogenic noise negatively impacts many species. One of the more insidious effects of elevate... more Anthropogenic noise negatively impacts many species. One of the more insidious effects of elevated noise levels is the reduction in area over which animals are able to acoustically communicate, often termed communication masking. This study utilizes modeling approaches to evaluate relative levels of masking for 4 baleen whale species from the combination of current ambient noise conditions and noise from discrete vessels operating in the Stellwagen Bank National Marine Sanctuary. Acoustic data were collected using bottom-mounted autonomous recorders. One day was analyzed for each of 5 different species-specific sound types, corresponding to peaks in occurrence of fin and humpback whale songs, humpback whale social sounds, minke whale pulse trains and North Atlantic right whale gunshots. Source levels for animals and 3 categories of vessels were calculated empirically; sound propagation was modeled using Bellhop ray tracing. An agent-based modeling framework was used to calculate changes in communication space (CS) in comparison to reference conditions (10 dB lower than current ambient noise). In these singleday snapshots, current ambient noise and noise from vessels for which automatic identification system (AIS) data were available contribute most heavily to loss of CS, followed by whale-watching and fishing vessels. Right whale gunshots experience the least amount of masking, while fin, humpback and minke whale signals experience masking levels of 80% or more. While these results incorporate several simplifying assumptions, this study further develops the framework by which to comparatively quantify masking, providing information on the relative degree of masking experienced between species and allowing for important insights on the relative contributions of different anthropogenic sound sources.
JASA Express Letters
This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, pas... more This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution. The format is a hybrid that uses 1 Hz resolution up to 455 Hz and millidecade frequency bands above 455 Hz. This hybrid is appropriate for many types of soundscape analysis, including detecting different types of soundscapes and regulatory applications like computing weighted sound exposure levels. Hybrid millidecade files are compressed compared to the 1 Hz equivalent such that one research center could feasibly store data from hundreds of projects for sharing among researchers globally. V
Endangered Species Research, 2016
The Gulf of Mexico ecosystem represents the intersection between high marine biodiversity and ext... more The Gulf of Mexico ecosystem represents the intersection between high marine biodiversity and extensive human use and impact. Anthropogenic marine activities are prominent in the Gulf, prompting concern regarding impacts of chronic elevated noise throughout the marine ecosystem. Since sound is a critical component of the marine environment and many marine animals in the Gulf utilize sound in different aspects of their life history, their basic ecology may be negatively affected by elevated anthropogenic noise. While there are data gaps regarding the impacts of noise on marine organisms, it is crucial to understand current ambient noise conditions to evaluate the implications of noise for the Gulf ecosystem. Ambient noise measurements provide a mechanism by which to sample the cumulative acoustic activity of an ecosystem, and holistically evaluate biotic, environmental, and human-induced acoustic contributions to the overall environment. In this study, acoustic data were collected at 7 sites in the northeastern Gulf of Mexico between July 2010 and February 2012. Ambient noise is presented in 3 frequency bands (low frequency [10-500 Hz], mid-frequency [500-1000 Hz], and high frequency [1000-3150 Hz]), with median sound levels of 112, 90, and 93 dB (re 1 μPa), respectively. Abiotic and anthropogenic noise sources significantly contributed to the ambient noise environment; however, seismic survey noise dominated the noise environment and chronically elevated noise levels across several paramount marine habitats. This study describes current noise conditions across the Gulf of Mexico with an intent to inform noise management strategies and investigate the potential ecological implications of elevated ambient noise.
Progress in Oceanography, 2015
OCEANS …, 2011
The possible effects of anthropogenic noise on the marine environment is becoming an important to... more The possible effects of anthropogenic noise on the marine environment is becoming an important topic in the oceanic community. The exploration for fossil-fuel or alternative energy and the construction of facilities to support these endeavors often ...
Advances in Experimental Medicine and Biology, 2016
In September and October 2011, a seismic survey took place in Baffin Bay, Western Greenland, in c... more In September and October 2011, a seismic survey took place in Baffin Bay, Western Greenland, in close proximity to a marine protected area (MPA). As part of the mitigation effort, five bottom-mounted marine acoustic recording units (MARUs) collected data that were used for the purpose of measuring temporal and spectral features from each impulsive event, providing a high-resolution record of seismic reverberation persistent after the direct impulse. Results were compared with ambient-noise levels as computed after the seismic survey to evidence that as a consequence of a series of repeating seismic impulses, sustained elevated levels create the potential for masking.