C. Clark - Academia.edu (original) (raw)

Papers by C. Clark

OCEANS '86, 1986

An a c o u s t i c s t u d y was conducted off Point Barrow, Alaska in the springs of 1984 and 19... more An a c o u s t i c s t u d y was conducted off Point Barrow, Alaska in the springs of 1984 and 1985 on t h e bowhead whale, Balaena mysticetus. during their annual migration. Multi-channel tape recordings were made u s i n g a r r a y s of sonobuoys, and whales were a c o u s t i c a l l y l o c a t e d u s i n g a customize hardware and software system specifically designed for performing s o p h i s t i c a t e d s i g n a l a n a l y s e s. The system was f i e l d c a l i b r a t e d o u t t o a d i s t a n c e of 4.

Environmental Management, 2008

In 2006, we used the U.S. Coast Guard's Automatic Identification System (AIS) to describe pattern... more In 2006, we used the U.S. Coast Guard's Automatic Identification System (AIS) to describe patterns of large commercial ship traffic within a U.S. National Marine Sanctuary located off the coast of Massachusetts. We found that 541 large commercial vessels transited the greater sanctuary 3413 times during the year. Cargo ships, tankers, and tug/tows constituted 78% of the vessels and 82% of the total transits. Cargo ships, tankers, and cruise ships predominantly used the designated Boston Traffic Separation Scheme, while tug/tow traffic was concentrated in the western and northern portions of the sanctuary. We combined AIS data with low-frequency acoustic data from an array of nine autonomous recording units analyzed for 2 months in 2006. Analysis of received sound levels (10-1000 Hz, root-mean-square pressure re 1 lPa ± SE) averaged 119.5 ± 0.3 dB at high-traffic locations. Hightraffic locations experienced double the acoustic power of less trafficked locations for the majority of the time period analyzed. Average source level estimates (71-141 Hz, rootmean-square pressure re 1 lPa ± SE) for individual vessels ranged from 158 ± 2 dB (research vessel) to 186 ± 2 dB (oil tanker). Tankers were estimated to contribute 2 times more acoustic power to the region than cargo ships, and more than 100 times more than research vessels. Our results indicate that noise produced by large commercial vessels was at levels and within frequencies that warrant concern among managers regarding the ability of endangered whales to maintain acoustic contact within greater sanctuary waters.

The function of song has been well studied in numerous taxa and plays a role in mediating both in... more The function of song has been well studied in numerous taxa and plays a role in mediating both intersexual and intrasexual interactions. Humpback whales are among few mammals who sing, but the role of sexual selection on song in this species is poorly understood. While one predominant hypothesis is that song mediates male–male interactions, the mechanism by which this may occur has never been explored. We applied metrics typically used to assess songbird interactions to examine song sequences and movement patterns of humpback whale singers. We found that males altered their song presentation in the presence of other singers; focal males increased the rate at which they switched between phrase types (p = 0.005), and tended to increase the overall evenness of their song presentation (p = 0.06) after a second male began singing. Two-singer dyads overlapped their song sequences significantly more than expected by chance. Spatial analyses revealed that change in distance between singers was related to whether both males kept singing (p = 0.012), with close approaches leading to song cessation. Overall, acoustic interactions resemble known mechanisms of mediating intrasexual interactions in songbirds. Future work should focus on more precisely resolving how changes in song presentation may be used in competition between singing males.

Animal Conservation, 2001

The human contribution to ambient noise in the ocean has increased over the past 50 years, and is... more The human contribution to ambient noise in the ocean has increased over the past 50 years, and is dominated by low-frequency (LF) sound (frequencies <1000 Hz) from shipping, oil and gas development, defence-related and research activities. Mysticete whales, including six endangered species, may be at risk from this noise pollution because all species produce and probably perceive low-frequency sound. We conducted a manipulative field experiment to test the effects of loud, LF noise on foraging fin blue (B. musculus) and (Balaenoptera physalus) whales off San Nicolas Island, California. Naive observers used a combination of attached tracking devices, ship-based surveys, aerial surveys, photo-identification and passive monitoring of vocal behaviour to examine the behaviour and distribution of whales when a loud LF source (US Navy SURTASS LFA) was and was not transmitting. During transmission, 12-30% of the estimated received levels of LFA of whales in the study area exceeded 140 dB re 1 µPa. However, whales continued to be seen foraging in the region. Overall, whale encounter rates and diving behaviour appeared to be more strongly linked to changes in prey abundance associated with oceanographic parameters than to LF sound transmissions. In some cases, whale vocal behaviour was significantly different between experimental and non-experimental periods. However, these differences were not consistent and did not appear to be related to LF sound transmissions. At the spatial and temporal scales examined, we found no obvious responses of whales to a loud, anthropogenic, LF sound. We suggest that the cumulative effects of anthropogenic LF noise over larger temporal and spatial scales than examined here may be a more important consideration for management agencies.

Marine Mammal Science, 2001

MARINE MAMMAL SCIENCE, 17(4):75 1-768 (October 2001) 0 2001 by the Society for Marine Mammalogy .... more MARINE MAMMAL SCIENCE, 17(4):75 1-768 (October 2001) 0 2001 by the Society for Marine Mammalogy ... ACOUSTIC DETECTIONS OF SINGING HUMPBACK WHALES IN DEEP WATERS OFF THE BRITISH ISLES ... RUSSELL A. CHARIF Bioacoustics Research ...

Animal Conservation, 2014

Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For marine specie... more 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. Acoustic quality of critical whale habitats R. Williams et al. 2 Animal Conservation •• (2013) ••-••

Papers: Bioacoustics by C. Clark

Biologists and engineers from Cornell have installed arrays of autonomous seafloor recorders in m... more Biologists and engineers from Cornell have installed arrays of autonomous seafloor recorders in multiple ocean habitats. These systems are designed to continuously monitor for the occurrence of endangered whales, particularly right whales; provide critical data on whale seasonal occurrence, distribution and relative numbers; and evaluate potential noise impacts from manmade activities and commercial shipping. Recent studies have been conducted in Massachusetts Bay around commercial LNG ports, the Arctic Ocean at seismic study locations, and in New York waters extending to the shelf edge. In combination with Cornell‐developed MATLAB‐ and JAVA‐based software applications, these seafloor recorders have been utilized to evaluate seasonal whale presence, calculate levels of commercial shipping and construction noise, and locate and track the movements and behaviors of individual whales under different acoustic conditions. Cornell and ocean engineers from the Woods Hole Oceanographic Institution have installed an operational network of autodetection buoys off New England to provide near‐real‐time data on right whale presence to transiting LNG vessels, government agencies, and public entities. When combined, the seafloor and autodetection buoy systems provide a powerful mechanism for understanding whale behavioral ecology and describing their acoustic habitats, while mitigating the risks from ship strike and noise exposure.

Abstract Data from two acoustic monitoring networks operating off New England in an area frequent... more Abstract
Data from two acoustic monitoring networks operating off New England in an area frequented by whales reveal acoustic features of those habitats. These seafloor and moored systems continuously sample the acoustic environment, and resultant data provide mechanisms for mapping, quantifying, and describing the spatio‐spectral‐temporal variability of the acoustic habitat over ecologically meaningful scales. By focusing on species‐specific frequency bands used by fin, humpback, and right whales for long‐range communication, we are beginning to measure the acoustic dynamics of their primary communication channels. Results reveal the extent to which different sources of sound in the ocean, both natural and man‐made, influence the probability of whale communication. In some habitats with high rates of vessel traffic and high levels of vessel noise, the predicted area over which animals can communicate is reduced to a small proportion of what it would be under quiet conditions. The dynamics of this masking effect are highly variable and vary by species. When considered from a large‐scale and behavioral ecological perspective, this reduction in acoustic habitat, as measured in terms of the proportional loss of communication space, likely represents a significant loss for species in which acoustic communication is known to serve critical biological functions.

A moored buoy system for automatic detection of endangered North Atlantic right whale (NARW) cont... more A moored buoy system for automatic detection of endangered North Atlantic right whale (NARW) contacts was developed to provide near-real-time information on the presence of vocalizing whales. The marine components include the WHOI buoy platform (mooring, hydrophone, power system, surface expression, antennae) and Cornell buoy electronics (housing, analog interface hardware, GPS, embedded computer, detection engine, and telemetry hardware). Shore-side Cornell components include telemetry equipment, server hardware and processing software, database, and interfaces for data annotation, access, and visualization. The buoy hardware/software system is capable of capturing and ranking NARW contact candidates as 2s, 2000Hz sampled audio clips. Location, timestamp and other metadata associated with each audio clip are assembled and uploaded via satellite for processing. Human analysts regularly annotate incoming data, resulting in a curated database of NARW detections. Periodic 'health and status' data allow for confirmation that buoys are functional. Regular voltage reporting helps predict required maintenance. Following initial implementations of the system in 2005, a series of successes and failures have led to system improvements in the buoy mooring, electronics, and server components. Deployments have progressed from prototype near-shore units to an operational network continuously monitoring the shipping lanes off Boston to meet ship strike mitigation requirements.

— The possible effects of anthropogenic noise on the marine environment is becoming an important ... 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 requires sizable construction efforts; which usually require permitting to study the impact of noise on the environment. Of particular interest is the variety of data products used to influence environmental impact reports and the processing time required to generate these data from large amounts of passive acoustic recordings. This paper outlines work being done by the Bioacoustics Research Program at Cornell University and the Lab of Ornithology, (BRP) for developing MATLAB tools in support of environmental compliance reporting. Due to the success of acoustic monitoring, understanding acoustic signatures is now becoming part of environmental impact assessment and required compliance for permitting. BRP has leveraged various existing tools and capabilities which result in integrated special purpose software tools within a MATLAB toolbox called SEDNA 1. SEDNA incorporates various tools to measure acute and chronic noise levels, detect and classify marine mammal vocalizations, and compute various metrics such as receive levels, signal excess, masking and communication space. This work will summarize the high performance computing strategy used in the SEDNA Toolbox along with the capability to integrate various layers of data within a modeling framework that incorporates ambient noise, vessel and animal data. Finally, the work will demonstrate the power of this approach through animated data visualization, showing animal, vessel and ambient noise integrated over relatively large temporal and spatial scales. 1 In Inuit mythology, Sedna (Inuktitut Sanna) is the goddess of the sea and marine animals. http://en.wikipedia.org/wiki/Sedna_(mythology).

OCEANS '86, 1986

An a c o u s t i c s t u d y was conducted off Point Barrow, Alaska in the springs of 1984 and 19... more An a c o u s t i c s t u d y was conducted off Point Barrow, Alaska in the springs of 1984 and 1985 on t h e bowhead whale, Balaena mysticetus. during their annual migration. Multi-channel tape recordings were made u s i n g a r r a y s of sonobuoys, and whales were a c o u s t i c a l l y l o c a t e d u s i n g a customize hardware and software system specifically designed for performing s o p h i s t i c a t e d s i g n a l a n a l y s e s. The system was f i e l d c a l i b r a t e d o u t t o a d i s t a n c e of 4.

Environmental Management, 2008

In 2006, we used the U.S. Coast Guard's Automatic Identification System (AIS) to describe pattern... more In 2006, we used the U.S. Coast Guard's Automatic Identification System (AIS) to describe patterns of large commercial ship traffic within a U.S. National Marine Sanctuary located off the coast of Massachusetts. We found that 541 large commercial vessels transited the greater sanctuary 3413 times during the year. Cargo ships, tankers, and tug/tows constituted 78% of the vessels and 82% of the total transits. Cargo ships, tankers, and cruise ships predominantly used the designated Boston Traffic Separation Scheme, while tug/tow traffic was concentrated in the western and northern portions of the sanctuary. We combined AIS data with low-frequency acoustic data from an array of nine autonomous recording units analyzed for 2 months in 2006. Analysis of received sound levels (10-1000 Hz, root-mean-square pressure re 1 lPa ± SE) averaged 119.5 ± 0.3 dB at high-traffic locations. Hightraffic locations experienced double the acoustic power of less trafficked locations for the majority of the time period analyzed. Average source level estimates (71-141 Hz, rootmean-square pressure re 1 lPa ± SE) for individual vessels ranged from 158 ± 2 dB (research vessel) to 186 ± 2 dB (oil tanker). Tankers were estimated to contribute 2 times more acoustic power to the region than cargo ships, and more than 100 times more than research vessels. Our results indicate that noise produced by large commercial vessels was at levels and within frequencies that warrant concern among managers regarding the ability of endangered whales to maintain acoustic contact within greater sanctuary waters.

The function of song has been well studied in numerous taxa and plays a role in mediating both in... more The function of song has been well studied in numerous taxa and plays a role in mediating both intersexual and intrasexual interactions. Humpback whales are among few mammals who sing, but the role of sexual selection on song in this species is poorly understood. While one predominant hypothesis is that song mediates male–male interactions, the mechanism by which this may occur has never been explored. We applied metrics typically used to assess songbird interactions to examine song sequences and movement patterns of humpback whale singers. We found that males altered their song presentation in the presence of other singers; focal males increased the rate at which they switched between phrase types (p = 0.005), and tended to increase the overall evenness of their song presentation (p = 0.06) after a second male began singing. Two-singer dyads overlapped their song sequences significantly more than expected by chance. Spatial analyses revealed that change in distance between singers was related to whether both males kept singing (p = 0.012), with close approaches leading to song cessation. Overall, acoustic interactions resemble known mechanisms of mediating intrasexual interactions in songbirds. Future work should focus on more precisely resolving how changes in song presentation may be used in competition between singing males.

Animal Conservation, 2001

The human contribution to ambient noise in the ocean has increased over the past 50 years, and is... more The human contribution to ambient noise in the ocean has increased over the past 50 years, and is dominated by low-frequency (LF) sound (frequencies <1000 Hz) from shipping, oil and gas development, defence-related and research activities. Mysticete whales, including six endangered species, may be at risk from this noise pollution because all species produce and probably perceive low-frequency sound. We conducted a manipulative field experiment to test the effects of loud, LF noise on foraging fin blue (B. musculus) and (Balaenoptera physalus) whales off San Nicolas Island, California. Naive observers used a combination of attached tracking devices, ship-based surveys, aerial surveys, photo-identification and passive monitoring of vocal behaviour to examine the behaviour and distribution of whales when a loud LF source (US Navy SURTASS LFA) was and was not transmitting. During transmission, 12-30% of the estimated received levels of LFA of whales in the study area exceeded 140 dB re 1 µPa. However, whales continued to be seen foraging in the region. Overall, whale encounter rates and diving behaviour appeared to be more strongly linked to changes in prey abundance associated with oceanographic parameters than to LF sound transmissions. In some cases, whale vocal behaviour was significantly different between experimental and non-experimental periods. However, these differences were not consistent and did not appear to be related to LF sound transmissions. At the spatial and temporal scales examined, we found no obvious responses of whales to a loud, anthropogenic, LF sound. We suggest that the cumulative effects of anthropogenic LF noise over larger temporal and spatial scales than examined here may be a more important consideration for management agencies.

Marine Mammal Science, 2001

MARINE MAMMAL SCIENCE, 17(4):75 1-768 (October 2001) 0 2001 by the Society for Marine Mammalogy .... more MARINE MAMMAL SCIENCE, 17(4):75 1-768 (October 2001) 0 2001 by the Society for Marine Mammalogy ... ACOUSTIC DETECTIONS OF SINGING HUMPBACK WHALES IN DEEP WATERS OFF THE BRITISH ISLES ... RUSSELL A. CHARIF Bioacoustics Research ...

Animal Conservation, 2014

Habitat loss is a leading cause of biodiversity loss in terrestrial ecosystems. For marine specie... more 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. Acoustic quality of critical whale habitats R. Williams et al. 2 Animal Conservation •• (2013) ••-••

Biologists and engineers from Cornell have installed arrays of autonomous seafloor recorders in m... more Biologists and engineers from Cornell have installed arrays of autonomous seafloor recorders in multiple ocean habitats. These systems are designed to continuously monitor for the occurrence of endangered whales, particularly right whales; provide critical data on whale seasonal occurrence, distribution and relative numbers; and evaluate potential noise impacts from manmade activities and commercial shipping. Recent studies have been conducted in Massachusetts Bay around commercial LNG ports, the Arctic Ocean at seismic study locations, and in New York waters extending to the shelf edge. In combination with Cornell‐developed MATLAB‐ and JAVA‐based software applications, these seafloor recorders have been utilized to evaluate seasonal whale presence, calculate levels of commercial shipping and construction noise, and locate and track the movements and behaviors of individual whales under different acoustic conditions. Cornell and ocean engineers from the Woods Hole Oceanographic Institution have installed an operational network of autodetection buoys off New England to provide near‐real‐time data on right whale presence to transiting LNG vessels, government agencies, and public entities. When combined, the seafloor and autodetection buoy systems provide a powerful mechanism for understanding whale behavioral ecology and describing their acoustic habitats, while mitigating the risks from ship strike and noise exposure.

Abstract Data from two acoustic monitoring networks operating off New England in an area frequent... more Abstract
Data from two acoustic monitoring networks operating off New England in an area frequented by whales reveal acoustic features of those habitats. These seafloor and moored systems continuously sample the acoustic environment, and resultant data provide mechanisms for mapping, quantifying, and describing the spatio‐spectral‐temporal variability of the acoustic habitat over ecologically meaningful scales. By focusing on species‐specific frequency bands used by fin, humpback, and right whales for long‐range communication, we are beginning to measure the acoustic dynamics of their primary communication channels. Results reveal the extent to which different sources of sound in the ocean, both natural and man‐made, influence the probability of whale communication. In some habitats with high rates of vessel traffic and high levels of vessel noise, the predicted area over which animals can communicate is reduced to a small proportion of what it would be under quiet conditions. The dynamics of this masking effect are highly variable and vary by species. When considered from a large‐scale and behavioral ecological perspective, this reduction in acoustic habitat, as measured in terms of the proportional loss of communication space, likely represents a significant loss for species in which acoustic communication is known to serve critical biological functions.

A moored buoy system for automatic detection of endangered North Atlantic right whale (NARW) cont... more A moored buoy system for automatic detection of endangered North Atlantic right whale (NARW) contacts was developed to provide near-real-time information on the presence of vocalizing whales. The marine components include the WHOI buoy platform (mooring, hydrophone, power system, surface expression, antennae) and Cornell buoy electronics (housing, analog interface hardware, GPS, embedded computer, detection engine, and telemetry hardware). Shore-side Cornell components include telemetry equipment, server hardware and processing software, database, and interfaces for data annotation, access, and visualization. The buoy hardware/software system is capable of capturing and ranking NARW contact candidates as 2s, 2000Hz sampled audio clips. Location, timestamp and other metadata associated with each audio clip are assembled and uploaded via satellite for processing. Human analysts regularly annotate incoming data, resulting in a curated database of NARW detections. Periodic 'health and status' data allow for confirmation that buoys are functional. Regular voltage reporting helps predict required maintenance. Following initial implementations of the system in 2005, a series of successes and failures have led to system improvements in the buoy mooring, electronics, and server components. Deployments have progressed from prototype near-shore units to an operational network continuously monitoring the shipping lanes off Boston to meet ship strike mitigation requirements.

— The possible effects of anthropogenic noise on the marine environment is becoming an important ... 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 requires sizable construction efforts; which usually require permitting to study the impact of noise on the environment. Of particular interest is the variety of data products used to influence environmental impact reports and the processing time required to generate these data from large amounts of passive acoustic recordings. This paper outlines work being done by the Bioacoustics Research Program at Cornell University and the Lab of Ornithology, (BRP) for developing MATLAB tools in support of environmental compliance reporting. Due to the success of acoustic monitoring, understanding acoustic signatures is now becoming part of environmental impact assessment and required compliance for permitting. BRP has leveraged various existing tools and capabilities which result in integrated special purpose software tools within a MATLAB toolbox called SEDNA 1. SEDNA incorporates various tools to measure acute and chronic noise levels, detect and classify marine mammal vocalizations, and compute various metrics such as receive levels, signal excess, masking and communication space. This work will summarize the high performance computing strategy used in the SEDNA Toolbox along with the capability to integrate various layers of data within a modeling framework that incorporates ambient noise, vessel and animal data. Finally, the work will demonstrate the power of this approach through animated data visualization, showing animal, vessel and ambient noise integrated over relatively large temporal and spatial scales. 1 In Inuit mythology, Sedna (Inuktitut Sanna) is the goddess of the sea and marine animals. http://en.wikipedia.org/wiki/Sedna_(mythology).