@article {58418, title = {Silent winters and rock-and-roll summers: The long-term effects of changing oceans on marine fish vocalization}, journal = {Ecological Indicators}, volume = {125}, year = {2021}, month = {Jan-06-2021}, pages = {107456}, abstract = {

The analysis of temporal trends and spatial patterns of marine sounds can provide crucial insights to assess the abundance, distribution, and behavior of fishes and of many other species. However, data on species-specific temporal and seasonal changes are still extremely limited. We report here the result of the longest recording ever conducted (five years, from 2014 to 2018) on fish vocalization. Findings from the Eastern Taiwan Strait (ETS) revealed a periodic fish chorusing pattern, with peaks in summer and almost complete silence, for ~2 months, during winter. Chorusing pattern was influenced by abiotic parameters, including temperature, tides and moon phase. We also report, for the first time, that extreme weather events (e.g., typhoons, storms with sediment resuspension) caused the cessation of the chorusing. The chorusing pattern explored in this long-term study provides important baseline data to understand the impact of climate change and of climate-driven extreme/episodic events on the phenology of fishes; this work also provides evidence that changes in the ambient conditions might significantly alter the phenology of vocalizing marine species.

}, keywords = {acoustic indices, Behavior, Climate-driven episodic events, Fish vocalization, Marine soundscape, Passive acoustic recordings}, issn = {1470160X}, doi = {10.1016/j.ecolind.2021.107456}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X21001217}, author = {Siddagangaiah, Shashidhar and Chen, Chi-Fang and Hu, Wei-Chun and Danovaro, Roberto and Pieretti, Nadia} } @article {58402, title = {Rapid coral reef assessment using 3D modelling and acoustics: acoustic indices correlate to fish abundance, diversity and environmental indicators in West Papua, Indonesia}, year = {2021}, abstract = {

Background
Providing coral reef systems with the greatest chance of survival requires effective assessment and monitoring to guide management at a range of scales from community to government. The development of rapid monitoring approaches amenable to collection at community level, yet recognised by policymakers, remains a challenge. Technologies can increase the scope of data collection. Two promising visual and audio approaches are (i) 3D habitat models, generated through photogrammetry from video footage, providing assessment of coral cover structural metrics and (ii) audio, from which acoustic indices shown to correlate to vertebrate and invertebrate diversity, can be extracted.

Methods
We collected audio and video imagery using low cost underwater cameras (GoPro Hero7\™) from 34 reef samples from West Papua (Indonesia). Using photogrammetry one camera was used to generate 3D models of 4 m2 reef, the other was used to estimate fish abundance and collect audio to generate acoustic indices. We investigated relationships between acoustic metrics, fish abundance/diversity/functional groups, live coral cover and reef structural metrics.

Results
Generalized linear modelling identified significant but weak correlations between live coral cover and structural metrics extracted from 3D models and stronger relationships between live coral and fish abundance. Acoustic indices correlated to fish abundance, species richness and reef functional metrics associated with overfishing and algal control. Acoustic Evenness (1,200\–11,000 Hz) and Root Mean Square RMS (100\–1,200 Hz) were the best individual predictors overall suggesting traditional bioacoustic indices, providing information on sound energy and the variability in sound levels in specific frequency bands, can contribute to reef assessment.

Conclusion
Acoustics and 3D modelling contribute to low-cost, rapid reef assessment tools, amenable to community-level data collection, and generate information for coral reef management. Future work should explore whether 3D models of standardised transects and acoustic indices generated from low cost underwater cameras can replicate or support \‘gold standard\’ reef assessment methodologies recognised by policy makers in marine management.

}, keywords = {acoustic indices, coral reef, monitoring, Photogrammetry, Soundscape}, doi = {10.7717/peerj.10761}, url = {https://peerj.com/articles/10761}, author = {Peck, Mika and Tapilatu, Ricardo F. and Kurniati, Eveline and Rosado, Christopher} } @article {58393, title = {Mesopelagic Sound Scattering Layers of the High Arctic: Seasonal Variations in Biomass, Species Assemblage, and Trophic Relationships}, year = {2019}, abstract = {

Mesopelagic sound scattering layers (SSL) are ubiquitous in all oceans. Pelagic organisms within the SSL play important roles as prey for higher trophic levels and in climate regulation through the biological carbon pump. Yet, the biomass and species composition of SSL in the Arctic Ocean remain poorly documented, particularly in winter. A multifrequency echosounder detected a SSL north of Svalbard, from 79.8 to 81.4\°N, in January 2016, August 2016, and January 2017. Midwater trawl sampling confirmed that the SSL comprised zooplankton and pelagic fish of boreal and Arctic origins. Arctic cod dominated the fish assemblage in August and juvenile beaked redfish in January. The macrozooplankton community mainly comprised the medusa Cyanea capillata, the amphipod Themisto libellula, and the euphausiids Meganyctiphanes norvegica in August and Thysanoessa inermis in January. The SSL was located in the Atlantic Water mass, between 200\–700 m in August and between 50\–500 m in January. In January, the SSL was shallower and weaker above the deeper basin, where less Atlantic Water penetrated. The energy content available in the form of lipids within the SSL was significantly higher in summer than winter. The biomass within the SSL was \>12-fold higher in summer, and the diversity of fish was slightly higher than in winter (12 vs. 9 species). We suggest that these differences are mainly related to life history and ontogenetic changes resulting in a descent toward the seafloor, outside the mesopelagic layer, in winter. In addition, some fish species of boreal origin, such as the spotted barracudina, did not seem to survive the polar night when advected from the Atlantic into the Arctic. Others, mainly juvenile beaked redfish, were abundant in both summer and winter, implying that the species can survive the polar night and possibly extend its range into the high Arctic. Fatty-acid trophic markers revealed that Arctic cod mainly fed on calanoid copepods while juvenile beaked redfish targeted krill (Thysanoessa spp.). The relatively high biomass of Arctic cod in August and of redfish in January thus suggests a shift within the SSL, from a Calanus-based food web in summer to a krill-based food web during winter.

}, keywords = {Arctic and boreal ecosystems, Barents Sea, Boreogadus saida, fatty acid trophic markers, mesopelagic fish and zooplankton, seasonality, Sebastes, Svalbard}, doi = {10.3389/fmars.2019.00364}, author = {Geoffroy, Maxime and Daase, Malin and Cusa, Marine and Darnis, G{\'e}rald and Graeve, Martin and Santana Hern{\'a}ndez, N{\'e}stor and Berge, J{\o}rgen and Renaud, Paul E. and Cottier, Finlo and Falk-Petersen, Stig} } @article {58172, title = {Techniques for distinguishing between impulsive and non-impulsive sound in the context of regulating sound exposure for marine mammals}, journal = {The Journal of the Acoustical Society of America}, volume = {147}, year = {2020}, month = {Jan-04-2020}, pages = {2159 - 2176}, abstract = {

Regulations designed to mitigate the effects of man-made sounds on marine mammal hearing specify maximum daily sound exposure levels. The limits are lower for impulsive than non-impulsive sounds. The regulations do not indicate how to quantify impulsiveness; instead sounds are grouped by properties at the source. To address this gap, three metrics of impulsiveness (kurtosis, crest factor, and the Harris impulse factor) were compared using values from random noise and real-world ocean sounds. Kurtosis is recommended for quantifying impulsiveness. Kurtosis greater than 40 indicates a sound is fully impulsive. Only sounds above the effective quiet threshold (EQT) are considered intense enough to accumulate over time and cause hearing injury. A functional definition for EQT is proposed: the auditory frequency-weighted sound pressure level (SPL) that could accumulate to cause temporary threshold shift from non-impulsive sound as described in Southall, Finneran, Reichmuth, Nachtigall, Ketten, Bowles, Ellison, Nowacek, and Tyack [(2019). Aquat. Mamm. 45, 125\–232]. It is known that impulsive sounds change to non-impulsive as these sounds propagate. This paper shows that this is not relevant for assessing hearing injury because sounds retain impulsive character when SPLs are above EQT. Sounds from vessels are normally considered non-impulsive; however, 66\% of vessels analyzed were impulsive when weighted for very-high frequency mammal hearing.

}, issn = {0001-4966}, doi = {10.1121/10.0000971}, url = {http://asa.scitation.org/doi/10.1121/10.0000971}, author = {Martin, S. Bruce and Lucke, Klaus and Barclay, David R.} } @article {58040, title = {Acoustic Complexity Index to assess benthic biodiversity of a partially protected area in the southwest of the UK}, year = {2020}, abstract = {

The soundscape of the marine environment is a relatively understudied area of ecology that has the potential to provide large amounts of information on biodiversity, reproductive behaviour, habitat selection, spawning and predator\–prey interactions. Biodiversity is often visually assessed and used as a proxy for ecosystem health. Visual assessment using divers or remote video methods can be expensive, and limited to times of good weather and water visibility. Previous studies have concluded that acoustic measures, such as the Acoustic Complexity Index (ACI), correlate with visual biodiversity estimates and offer an alternative to assess ecosystem health.

Here, the ACI measured over 5 years in a Marine Protected Area (MPA) in the UK, Lyme Bay, was analysed alongside another monitoring method, Baited Remote Underwater Video Systems (BRUVs). Two treatments were sampled annually in the summer from 2014 until 2018 with sites inside the MPA, as well as Open Control sites outside of the MPA.

Year by year correlations, which have been used elsewhere to test ACI, showed significant correlations with Number of Species and ACI. However, the sign of these correlations changed almost yearly, showing that more in-depth analyses are needed.

Multivariate analysis of the benthic assemblage composition (from BRUVs) was carried out by Permutational Multivariate Analysis of Variance (PERMANOVA) using Distance Matrices. Although not consistently correlating with univariate measures, the ACI was significantly interacting with the changing benthic assemblage composition, as it changed over time and protection (Inside vs Outside the MPA).

ACI showed potential to allude to shifting benthic communities, yet with no consistency when used alongside univariate measures of diversity. Although it is not without its own disadvantages, and thus should be developed further before implementation, the ACI could potentially reflect more complex changes to the benthos than simply the overall diversity.

}, keywords = {Acoustic Complexity Index, biodiversity, Marine Protected Area, Monitoring Tools}, doi = {10.1016/j.ecolind.2019.106019}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X19310155}, author = {Davies, Bede F.R. and Attrill, Martin J. and Holmes, Luke and Rees, Adam and Witt, Matthew J. and Sheehan, Emma V.} } @article {57973, title = {Undersea Noise Pollution and Harm: Source, Impacts and International Legal ControlAbstract}, journal = {Chinese Journal of Environmental Law}, volume = {3}, year = {2019}, month = {Mar-12-2019}, pages = {203 - 224}, abstract = {

Undersea noise is now being recognised as a major pollution problem on a global scale. Human activities, such as mercantile shipping, military activities and the exploration and exploitation of undersea minerals, have considerably increased undersea noise in the oceans in the last 50 years. Undersea noise causes stress in marine animals, increases risk of mortality by unbalancing predator-prey interactions and interferes with sound-based navigation and communication of marine animals. In the absence of appropriate regulation, undersea noise pollution and its implications for the marine environment will increase in the future. This article examines the international legal instruments of relevance to undersea noise pollution and investigates whether these instruments can sufficiently regulate undersea noise pollution. It is argued that they are currently inadequate. The article proposes a list of elements that might be used as a basis for an additional international legal regime on the prevention and control of undersea noise pollution, taking into account the recent focus by the UN General Assembly and other bodies on this issue.

}, doi = {10.1163/24686042-12340042}, url = {https://brill.com/view/journals/cjel/3/2/article-p203_4.xmlhttps://brill.com/view/journals/cjel/3/2/article-p203_4.xml}, author = {Solangi, Habib-ur-Rehman} } @conference {57915, title = {Field testing and performance evaluation of the Long-term Acoustic Real-Time Sensor for Polar Areas (LARA)}, year = {2019}, abstract = {

In the Arctic, in-situ measurement of the upper water column properties (e.g., salinity and temperature) has been a challenge because of the seasonal sea ice coverage. A Long-term Acoustic Real-Time Sensor for Polar Areas (LARA) was developed, field-tested in the shallow water off Oregon and its performance evaluated. The LARA utilizes a commercially available underwater profiler winch from NiGK, conductivity-temperature-depth (CTD) sensors, and a passive acoustic monitoring (PAM) systems. The sensor section consists of two modules: 1) a satellite antenna with a temperature and depth sensor (TD) and 2) a sensor buoy with a controller, a CTD, and a PAM. Using the two vertically separated temperature and pressure sensors, it is capable of detecting the presence of sea ice by sensing the oceanographic conditions in the upper water column. In addition, using the acoustic sensors, (1) surface wind speed can be estimated from the ambient noise level and (2) enable monitoring of marine mammal calling activity. The winch can be fully controllable from the sensor buoy by acoustic commands. It is capable of aborting an ascent in case sea ice coverage or a high sea state was detected. Although the sea ice detection algorithm could not be tested in Oregon waters, the LARA successfully repeated 94 profiles and transmitted CTD and acoustic detections data via satellite. The wind speed estimates by the PAM were in good agreement with the nearby buoy data. The PAM recorded various biological signals from 10 Hz to 60 kHz including vocalizations of fin, humpback, sperm whales and calls of Pacific white-sided dolphins. The system is capable of repeating 365 profiles or one profile per day for 1 year making it suitable for collecting high-resolution water column data in the extreme weather and water conditions of the Arctic.

}, keywords = {arctic, bio-acoustics, profiling, real-time detections}, author = {H. Matsumoto and J. Haxel and B. Kahn and L. Roche and A. Turpin and Klinck, Holger and R.P. Dziak and J. Childress and K. Sexton and T. Nakamura} } @article {57885, title = {Using Soundscapes to Assess Deep-Sea Benthic Ecosystems}, year = {2019}, abstract = {

Targets of deep-sea mining commonly coincide with biodiversity hotspots, such as hydrothermal vents. The resilience of these ecosystems relies on larval dispersal, which may be directed by habitat-specific soundscapes. We urge for a global effort to implement soundscape as a conservation tool to assess anthropogenic disruption to deep-sea benthic ecosystems.

}, doi = {10.1016/j.tree.2019.09.006}, author = {Lin, Tzu-Hao and Chen, Chong and Watanabe, Hiromi Kayama and Kawagucci, Shinsuke and Yamamoto, Hiroyuki and Akamatsu, Tomonari} } @article {57648, title = {Using acoustic metrics to characterize underwater acoustic biodiversity in the Southern Ocean}, year = {2019}, abstract = {

Acoustic metrics (AM) assist our interpretation of acoustic environments by aggregating a complex signal into a unique number. Numerous AM have been developed for terrestrial ecosystems, with applications ranging from rapid biodiversity assessments to characterizing habitat quality. However, there has been comparatively little research aimed at understanding how these metrics perform to characterize the acoustic features of marine habitats and their relation with ecosystem biodiversity. Our objectives were to 1) assess whether AM are able to capture the spectral and temporal differences between two distinct Antarctic marine acoustic environment types (i.e., pelagic vs. on-shelf), 2) evaluate the performance of a combination of AM compared to the signal full frequency spectrum to characterize marine mammals acoustic assemblages (i.e., species richness\–SR\–and species identity) and 3) estimate the contribution of SR to the local marine acoustic heterogeneity measured by single AM. We used 23 different AM to develop a supervised machine learning approach to discriminate between acoustic environments. AM performance was similar to the full spectrum, achieving correct classifications for SR levels of 58\% and 92\% for pelagic and on-shelf sites respectively and \> 88\% for species identities. Our analyses show that a combination of AM is a promising approach to characterize marine acoustic communities. It allows an intuitive ecological interpretation of passive acoustic data, which in the light of ongoing environmental changes, supports the holistic approach needed to detect and understand trends in species diversity, acoustic communities and underwater habitat quality.

}, keywords = {Acoustic metrics, Antarctic, community composition, marine acoustic environments, passive acoustic monitoring, species diversity}, doi = {10.1002/rse2.129}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/rse2.129}, author = {Roca, Irene T. and Van Opzeeland, Ilse}, editor = {Pettorelli, Nathalie and Quick, Nicola} } @article {57604, title = {Using acoustic metrics to characterize underwater acoustic biodiversity in the Southern Ocean}, year = {2019}, abstract = {

Acoustic metrics (AM) assist our interpretation of acoustic environments by aggregating a complex signal into a unique number. Numerous AM have been developed for terrestrial ecosystems, with applications ranging from rapid bio- diversity assessments to characterizing habitat quality. However, there has been comparatively little research aimed at understanding how these metrics perform to characterize the acoustic features of marine habitats and their relation with ecosystem biodiversity. Our objectives were to 1) assess whether AM are able to capture the spectral and temporal differences between two distinct Antarctic marine acoustic environment types (i.e., pelagic vs. on-shelf), 2) evaluate the performance of a combination of AM compared to the signal full frequency spectrum to characterize marine mammals acoustic assemblages (i.e., species richness\–SR\–and species identity) and 3) estimate the contribution of SR to the local marine acoustic heterogeneity measured by single AM. We used 23 differ- ent AM to develop a supervised machine learning approach to discriminate between acoustic environments. AM performance was similar to the full spec- trum, achieving correct classifications for SR levels of 58\% and 92\% for pelagic and on-shelf sites respectively and \> 88\% for species identities. Our analyses show that a combination of AM is a promising approach to characterize marine acoustic communities. It allows an intuitive ecological interpretation of passive acoustic data, which in the light of ongoing environmental changes, supports the holistic approach needed to detect and understand trends in species diver- sity, acoustic communities and underwater habitat quality.

}, keywords = {Acoustic metrics, Antarctic, community composition, marine acoustic environments, passive acoustic monitoring, species diversity}, doi = {10.1002/rse2.129}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/rse2.129}, author = {Roca, Irene T. and Van Opzeeland, Ilse}, editor = {Pettorelli, Nathalie and Quick, Nicola} } @article {57411, title = {Environmental information content of ocean ambient noise}, year = {2019}, abstract = {

In recent years, methods have been developed to estimate a variety of environmental parameters based on measurements of the ocean ambient noise. For example, noise has been used to estimate water depth using the passive fathometer technique and bottom loss estimated and used to invert for seabed parameters. There is also information in the noise about the water column sound speed, volume attenuation, and the sea-state. The Fisher information can be used to quantify the basic information available in the noise measurements and its inverse, the Cram\ér\–Rao lower bound (CRLB), provides the lower limit on the variance of an unbiased estimator of a particular parameter. The CRLB can be used to study the feasibility of various measurement configurations and parameter sensitivities. In this paper, the CRLB is developed for ocean ambient noise and the environmental information contained in the measurements is determined. The CRLBs provide an estimate of the underlying information in the data, however, it is independent of the estimation methodology. This is useful to determine if a given estimation method is reaching the lower bound. Results illustrating the bounds as well as sensitivities and performance of estimators are demonstrated using both simulations and data.

}, doi = {10.1121/1.5126520}, url = {http://asa.scitation.org/doi/10.1121/1.5126520}, author = {Siderius, Martin and Gebbie, John} } @article {57351, title = {An optimised passive acoustic sampling scheme to discriminate among coral reefs{\textquoteright} ecological states}, journal = {Ecological Indicators}, volume = {107}, year = {2019}, month = {Jan-12-2019}, pages = {105627}, abstract = {

In the present era of rapid global change, innovative monitoring methods can greatly enhance our ability to detect ecological disturbances and prioritise conservation areas in a timely and cost-effective manner. While Passive Acoustic Monitoring (PAM) has recently emerged as a promising tool for monitoring ecological states in marine environments, the specifics of how to apply this method remains poorly defined. In this study we examined how different combinations of sampling settings (frequency bandwidth, time of sampling (day/night), and sample duration) influenced the ability of two acoustic indices, the Sound Pressure Level (SPL) and the Acoustic Complexity Index (ACI), to discriminate different ecological states (ecostates) of coral reefs. We applied an iterative approach to select the most efficient and consistent combinations of sampling settings to use for these two acoustic indices, depending on the stability of their discriminating power across different time scales (successive days, moon phases, and seasons), and the minimum sampling effort required for reliable ecostate assessment. The ability of SPL and ACI to discriminate ecostate-specific soundscapes was more stable and required less sampling effort at nighttime. For indices calculated in the higher frequency band (\>2 kHz), very short recording times (\≤20 min divided into 5 s samples) were sufficient to discriminate ecostates, whereas longer recording times (\≥200 min divided into 5 min samples) were necessary when using indices calculated in the lower frequency bands (\<1 kHz). An optimised sampling scheme, i.e. the group of the five best combinations of settings to discern among coral reef ecostates, was determined at Reunion Island, Indian Ocean, then tested at New Caledonia, Pacific Ocean. Here, the classifications obtained through visual surveys and with the optimised acoustic sampling scheme were congruent. The concordance of our results with visual fish counts confirms the potential of ecoacoustics to rapidly and reliably characterise coral reefs\’ ecostate, allowing managers to prioritise conservation areas among numerous sites, and detect ecological changes over time. Our study provides clear guidelines for monitoring soundscapes by means of the ecoacoustic indices most widely used in the marine realm.

}, keywords = {Coral reefs, Ecoacoustic indices, Ecological state (ecostate), Marine habitats, passive acoustic monitoring, Sampling scheme}, issn = {1470160X}, doi = {10.1016/j.ecolind.2019.105627}, author = {Elise, Simon and Bailly, Arthur and Urbina-Barreto, Isabel and Mou-Tham, G{\'e}rard and Chiroleu, Fr{\'e}d{\'e}ric and Vigliola, Laurent and Robbins, William D. and Bruggemann, J. Henrich} } @article {57345, title = {Assessing key ecosystem functions through soundscapes: A new perspective from coral reefs}, journal = {Ecological Indicators}, volume = {107}, year = {2019}, month = {Jan-12-2019}, pages = {105623}, abstract = {

The functioning of tropical coral reefs is imperilled by climate change, overfishing, and decreasing water quality. Maintaining their capacity to provide goods and services will critically depend on our ability to monitor their functioning at appropriate spatial and temporal scales. Given the constraints of traditional methods to respond to those needs, the potential of complementary tools such as Passive Acoustic Monitoring (PAM) is emerging. Coral reef soundscapes (i.e. ambient sound) encompass sounds produced by numerous organisms. Soundscape characteristics quantified by ecoacoustic indices have been found to reflect general ecosystem properties, such as diversity and abundance of fishes, and coral cover. The present study tested, on the virtually pristine coral reefs around Europa Island, South-West Indian Ocean, the capacity of acoustic indices to assess key ecosystem functions. Soundscapes were recorded during 2 h, and ecosystem functions were evaluated using video footage of the fish assemblages and underwater photogrammetry of the benthic landscapes. We found significant and strong correlations between six ecoacoustic indices and six key ecosystem functions, including habitat features and fish assemblage characteristics. The six ecoacoustic indices were representative of several combinations of frequency, amplitude and time analysis domains, highlighting the diversity of the functional information conveyed by soundscapes. Our findings reveal that a 2 h daytime recording on a coral reef could provide sufficient acoustic information to characterise major ecosystem functions of a site. This should facilitate the detection of functional disturbances at temporal and spatial scales adapted to the rapidity of upcoming climate changes. Our results also highlight the potential of ecoacoustics to bring novel and relevant insights in the functioning of ecosystems.

}, keywords = {conservation, Coral reefs, Ecoacoustic indices, Key ecosystem functions, passive acoustic monitoring, Soundscape}, issn = {1470160X}, doi = {10.1016/j.ecolind.2019.105623}, author = {Elise, Simon and Urbina-Barreto, Isabel and Pinel, Romain and Mahamadaly, Vincent and Bureau, Sophie and Penin, Lucie and Adjeroud, Mehdi and Kulbicki, Michel and Bruggemann, J. Henrich} } @article {53523, title = {The Ocean as a Living Sensor: Environmental DNA and Acoustics for Detecting Marine Life}, year = {2018}, type = {Discussion Paper}, author = {Alison W. Watts and Jennifer L. Miksis-Olds} } @article {53442, title = {Improved visualization of large temporal series for the evaluation of good environmental status}, journal = {Applied Acoustics}, volume = {148}, year = {2019}, month = {Jan-05-2019}, pages = {55 - 61}, abstract = {

Passive acoustic monitoring of underwater sounds is an emerging discipline that can be used to guarantee that anthropogenic noise meets acceptable limits, to detect the presence of cetacean species, and to ensure sustainable exploitation of our oceans and seas. In this scenario, graphical representation techniques play a key role in helping to reveal seasonal structures of human made noises. Nevertheless, for very long temporal series, it might be challenging to find a graphic visualization technique that allows representing a time range that is long enough to capture these seasonal events, while at the same time preserving short isolated events. We propose a framework for the creation of such visualization techniques and analyze the different stages involved: data reduction, color encoding, and signal processing on graphs. All of this is applied to data from deployments in two marine protected areas in order to provide an acoustic panorama and identify seasonal events.

}, issn = {0003682X}, doi = {10.1016/j.apacoust.2018.12.009}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003682X18306261https://api.elsevier.com/content/article/PII:S0003682X18306261?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003682X18306261?httpAccept=text/plain}, author = {Miralles, Ram{\'o}n and Lara, Guillermo and Gosalbez, Jorge and Bosch, Ignacio and Le{\'o}n, Antonio} } @conference {53441, title = {Acoustic Diversity Classifier for Automated Marine Big Data Analysis}, booktitle = {2018 IEEE 30th International Conference on Tools with Artificial Intelligence (ICTAI)2018 IEEE 30th International Conference on Tools with Artificial Intelligence (ICTAI)}, year = {2018}, publisher = {IEEE}, organization = {IEEE}, address = {Volos, Greece}, abstract = {

In recent years, big data has increasingly drawn the attention of the R\&D community. With the advent of marine data, monitoring marine big data becomes a new trend that advocates for assessing human impact on marine data. Nevertheless, there is a lack of support for acoustic sounds classification in such environment, covering diverse data that can exist (i.e., fish sounds, human activities sounds and environmental sounds). In this paper, we cope with this gap by proposing a deep learning-based approach that enables to efficiently classify these acoustic sounds aiming at automating the support of marine sound analysis in big data architectures. A set of experiments have been conducted using a real marine dataset to demonstrate the feasibility and the effectiveness of our approach.

}, doi = {10.1109/ICTAI.2018.00029}, url = {https://ieeexplore.ieee.org/document/8576027/}, author = {Hachicha Belghith, Emna and Rioult, Francois and Bouzidi, Medjber} } @mastersthesis {53438, title = {Coral reef soundscapes: The use of passive acoustic monitoring for long-term ecological survey}, year = {2018}, school = {Curtin University}, type = {PhD}, abstract = {

Coral reefs provide ecosystem services to millions of people and are a habitat for almost one third of the world\’s named marine fish species. As the world\’s human population and the demand for natural resources expand, the states of most terrestrial and marine ecosystems continues to decline at an alarming rate. In the past century, coral reefs have suffered significant rates of deterioration, through a combination of stressors, including invasive species, climate change related disturbances and pollution. More recently, El Ni\ño events, combined with several major storm events have been connected with extensive bleaching and significant coral mortality, particularly in Australia\’s Great Barrier Reef (GBR).
The designation of marine protected areas (MPAs) worldwide, covering nearly 3\% of the world\’s oceans, is an example of the world\’s commitment towards safeguarding the future of marine ecosystems. However, to meet the demands and goals of marine management policies, there is a need for implementation of well-structured management plans. Fundamentals of effective management, conservation, research of ecosystems and natural resources are built on the ability to track patterns in space and time. This is where long-term monitoring and research can provide critical ecological insight.
Passive acoustic monitoring (PAM) is used to investigate environmental systems through the medium of sound. It permits natural physical, biological and anthropogenic sound sources to be monitored over long time frames and offers an additional approach to visual surveys of coral reefs. However, the full management applicability of PAM remains undetermined.
The aims of this research were to categorise biological reef sounds, identify and investigate temporal patterns of fish choruses, quantify the contribution of anthropogenic (ship) noise and determine how large disturbance events may influence soundscapes over time on Australia\’s Great Barrier Reef.
Lizard Island, situated in the GBR, was chosen as the primary location to conduct field work. The GBR supports over 1500 species of fish, 400 species of hard corals and an enormous variety of other life forms, making it an ideal location for investigating how PAM may have potential as a long-term coral reef monitoring tool. Lizard Island has been, and continues to be, a key location for coral reef research. Over the last 30 years, the Island\’s renowned research station has helped to support and foster a wealth of marine research projects.
Long-term monitoring in coral reefs has always been a significant challenge due to reefs being logistically difficult and expensive to access, highly heterogeneous and a demanding environment for equipment. This has meant that many surveys have been restricted to fine resolution \‘snapshot\’
studies, so that our understanding of larger scale ecosystem dynamics over longer time scales is more limited. Therefore, the combination of logistical support and access to relevant data that Lizard Island research station provides was a deciding factor for choosing this location.

The coral reefs surrounding Lizard Island in the GBR have a diverse soundscape that contains an array of bioacoustic phenomena, particularly biological choruses produced by soniferous fish. Six fish choruses identified around Lizard Island exhibited notable spatial and temporal patterns from 2014 to 2016. Several environmental variables had a significant influence on the timing and received levels of several of the fish choruses. Two out of the six detected choruses exhibited spectral and temporal characteristics similar to choruses produced by planktivorous fish species previously documented at these sites and elsewhere. Three of the six choruses appear to be undocumented and could hold information on the presence, abundance and dispersal patterns of important fish species, which may have long-term management applications. Several choruses displayed high site fidelity, indicating that particular sites may represent important habitat for fish species, such as fish spawning aggregations sites.
The contribution and subsequent impacts that anthropog enic noise may have in marine ecosystems, particularly in coral reefs, has gained substantial attention in the last decade. Vessels (commercial, recreational and research) are the key sources of anthropogenic noise in coral reef soundscapes around Lizard Island. Significant spatial differences in research vessel activity were present around Lizard Island, which led to several vessel traffic hotspots, in areas of high activity. Daily activity of commercial vessels was similar throughout the year, but a notable rise in recreational vessel density occurred during the start of the austral wet season, which coincides with peak biophonic activity in the form of fish choruses. The long-term noise contributions of research vessels were apparent at sites that had high levels of research boat activity, but were not observed at sites with low activity. Noise from commercial vessels raised soundscape sound levels at low frequencies (\< 500 Hz) at five of the six field sites. With commercial ship numbers and size continuing to increase, it is expected that vessel noise will be a growing contributor to coral reef soundscapes. Combined with elevated environmental disturbances from climate change, this is likely to be an important additional threat to coral ecosystems.
Lizard Island was exposed to a Category 4 cyclone in March 2015, which resulted in widespread damage to several areas of reef around the Island. The following year, large parts of the GBR experienced severe bleaching; including around Lizard Island which, resulted in substantial mortality of corals. Fish choruses were still present at sites that sustained significant cyclone damage, but a change in chorus energy attributes was observed. Sound recordings taken close to the start of the bleaching event did not reveal any discernible short-term changes to the soundscape. Recordings taken around Lizard Island in November and December 2016 contained five of the six choruses recorded pre-bleaching, also similar to those measured in the previous two years, which implies at least some short-term resilience. However, the long-term impact of these destructive disturbance events and how soundscapes and their key constituents will be affected is yet to be determined. A notable drop in low-frequency noise in 2016, post-bleaching, corresponds with a reduction in vessel activity in the same area, suggesting PAM may provide an indication of potential socio-economic impacts.

These findings highlight the utility of PAM for long-term monitoring and management of coral reefs, which is highly relevant in light of recent global disturbance events, particularly coral bleaching. Comparison of current and historical soundscape recordings made around Lizard Island over 25 years ago revealed long-term site fidelity of fish choruses. This indicates that soundscapes should be strongly considered as a long-term coral reef monitoring tool, with fish choruses showing potential as an ecological indicator of coral reef condition.
Future research should focus on extricating the temporal patterns associated with bioacoustic activity and determining the potential environmental drivers of biological choruses. Utilising and developing automatic signal processing techniques in pattern recognition would help progress this. This could then support technique development for direct identification of vocalising species, which would strongly increase the management applicability of PAM. Research efforts should also be made towards expanding soundscape monitoring across the GBR, with a focus on sampling areas that contain a range of live coral coverage.

}, author = {Jamie Neish McWilliam} } @mastersthesis {53423, title = {Listening to whales: Tying acoustics to ecology}, volume = {PhD}, year = {2018}, school = {University of Victoria}, type = {PhD}, abstract = {

The acoustic sense is vital to all life processes for whales. It defines their \‘active space\’, and the extent and nature of interactions with their surroundings. Yet, we are still learning the basics of most species\’ acoustic behaviours and vocal repertoires.
The ecology of gray whales (Eschrichtius robustus) is well known, however vocal behaviours are not well described outside of breeding lagoons. Bottom-stationed acoustic monitoring devices were deployed in Clayoquot Sound, west coast Vancouver Island to explore acoustics use outside of these areas. During migration the use of low frequency moan calls are prevalent, perhaps for group cohesion, with lead whales guiding followers. During the summer more inter-group calls (knocks, upsweeps) are employed. Here I explored the use of \‘motherese\’ calls between cow-calf pairs, and how this may mirror the weaning process. Photoperiod, increased ambient noise, threat perception, and vessel and aircraft presence elicited acoustic responses. Calling was also altered by social, behavioural, and physiological state. These results begin to show gray whales to be acoustically sensitive, with highly nuanced vocalising behaviours.
Acoustic methods afford monitoring at times and in places that would otherwise be impossible, and lends themselves to the study of rare or cryptic species. Ocean gliders with passive acoustic capacity were used to explore deep-coastal and shelf-break waters for large whale species. Humpback whales (Megaptera novaeangliae) were common on the shelf, whereas calls from fin (Balaenoptera physalus), blue (Balaenoptera musculus), sperm (Physeter macrocephalus), and possibly sei whales (Balaenoptera borealis) were heard in more offshore locations. Concurrent habitat data steams help establish area use and importance to these species. The surveys focus on submarine canyons that are thought to aggregate prey. Calls denote whale presence, whereas call type may suggest behaviour and habitat use. Calls described for feeding and breeding were heard for fin and blue whales, with distinct temporal distribution.

Acoustic techniques complement other ecological methods and can fill existing knowledge gaps in whale life histories. It can also help quantify the effect of human activities on whale populations and ocean soundscapes. These findings will inform management actions. I provide examples of management links to acoustic-ecological research.

}, author = {Rianna E. Burnham} } @article {53410, title = {An Empirical Mode Decomposition-based detection and classification approach for marine mammal vocal signals}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-12-2018}, pages = {3181 - 3190}, abstract = {

Detecting marine mammal vocalizations in underwater acoustic environments and classifying them to species level is typically an arduous manual analysis task for skilled bioacousticians. In recent years, machine learning and other automated algorithms have been explored for quickly detecting and classifying all sound sources in an ambient acoustic environment, but many of these still require a large training dataset compiled through time-intensive manual pre-processing. Here, an application of the signal decomposition technique Empirical Mode Decomposition (EMD) is pre- sented, which does not require a priori knowledge and quickly detects all sound sources in a given recording. The EMD detection process extracts the possible signals in a dataset for minimal quality control post-processing before moving onto the second phase: the EMD classification process. The EMD classification process uniquely identifies and labels most sound sources in a given environ- ment. Thirty-five recordings containing different marine mammal species and mooring hardware noises were tested with the new EMD detection and classification processes. Ultimately, these pro- cesses can be applied to acoustic index development and refinement.

}, issn = {0001-4966}, doi = {10.1121/1.5067389}, url = {http://asa.scitation.org/doi/10.1121/1.5067389}, author = {Seger, Kerri D. and Al-Badrawi, Mahdi H. and Kirsch, Nicholas J. and Lyons, Anthony P.} } @article {53327, title = {Source localization using a compact tetrahedral array}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1745 - 1745}, abstract = {

We localized sound sources collected on a compact tetrahedral hydrophone array in a continental shelf environment south of Block Island, Rhode Island. The tetrahedral array of phones, 0.5 m on a side, was deployed to monitor the underwater sound of construction and operation of the first offshore wind farm in the United States. Signals from shipping and marine mammals, including fin whales, humpback whales, and right whales, were detected on the array. Directions of arrival (DOAs) for a number of signals were computed using a time difference of arrival technique. Given the DOAs, ranges were estimated using supervised machine learning techniques outlined by Niu et al. (JASA, 2017). The approach was tested using simulated data from Kraken assuming environmental information consistent with this continental shelf environment. Performance on signals from individual ships and marine mammals is presented. Ship localizations are compared to Automated Identification System (AIS) fixes. An error analysis is also presented. [Work supported by the Office of Naval Research and the Bureau of Ocean Energy Management.]

}, issn = {0001-4966}, doi = {10.1121/1.5067739}, url = {http://asa.scitation.org/doi/10.1121/1.5067739}, author = {Potty, Gopu R. and Tripathy, Aditi and Tazawa, Makio and Amaral, Jennifer and Vigness-Raposa, Kathleen J. and Lin, Ying-Tsong and Newhall, Arthur} } @article {53322, title = {How Can We Understand Freshwater Soundscapes Without Fish Sound Descriptions?}, journal = {Fisheries}, year = {2018}, month = {Dec-10-2019}, abstract = {

The ecological importance of the freshwater soundscape is just beginning to be recognized by society. Scientists are beginning to apply Passive Acoustic Monitoring (PAM) methods that are well established in marine systems to freshwater systems to map spatial and temporal patterns of behaviors associated with fish sounds as well as noise impacts on them. Unfortunately, these efforts are greatly hampered by a critical lack of data on the sources of sounds that make up the soundscape of freshwater habitats. A review of the literature finds that only 87 species have been reported to produce sounds in North America and Europe over the last 200 years, accounting for 5\% of the known freshwater fish diversity. The problem is exacerbated by the general failure of researchers to report the detailed statistical descriptions of fish sound characteristics that are necessary to develop PAM programs. We suggest that publishers and editors should do more to encourage reporting of statistical properties of fish sounds. In addition, we call for research, academic, and government agencies to develop regional libraries of fish sounds to aid in PAM and anthropogenic noise impact studies.

}, doi = {10.1002/fsh.10190}, url = {http://doi.wiley.com/10.1002/fsh.10190}, author = {Bolgan, Marta and Juanes, Francis} } @article {53315, title = {Relationship between cetacean presence, their prey, and oceanographic conditions at an offshore pelagic environment}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1921 - 1921}, abstract = {

Large mobile predators take advantage of offshore pelagic environments that tend to be surveyed at a low temporal scale. We present results from a one-year observation of passive and active acoustics, as well as oceanographic measures, taken at a moored location 150 nmi offshore southern California in 4000 m deep pelagic waters. The passive acoustic data shows presence of delphinids and baleen, sperm, and beaked whales throughout the recording period with species-specific seasonal occurrence. Variability in small pelagics, krill, and diel vertical migrators is evident from the active acoustic data. Multiple upwelling events and associated changes in dissolved oxygen at 500 m water depth, as well as in surface waters, were also recorded over the year. We will present results on the relationships among oceanographic variability, presence of pelagic species, and top predator presence. This study will provide valuable information on ecosystem processes in meso- and epipelagic waters on a relatively small spatial scale but very fine temporal scale.

}, issn = {0001-4966}, doi = {10.1121/1.5068413}, url = {http://asa.scitation.org/doi/10.1121/1.5068413}, author = {Baumann-Pickering, Simone and Trickey, Jennifer S. and Rice, Ally and {\v S}irovi{\'c}, Ana and Renfree, Josiah and Demer, David A.} } @article {53304, title = {Vertical line array tilt revealed through snapping shrimp noise}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1921 - 1921}, abstract = {

The shallow-water acoustic variability experiment (SAVEX15), conducted in the East China Sea, unexpectedly recorded a great deal of snapping shrimp noise on a 16-element (56-m length) vertical line array deployed in 100-m water depths. These impulsive events can be used to find the tilt of the moored array which was caused by the strong ocean currents in the area. In this environment, the recorded snaps of bottom-dwelling shrimp within a radius of more than 500 m were largely separated from one another in time, and coherent time domain beamforming was successful in localizing snaps in time and range. The sparse and impulse nature of the snaps allowed for a simple normalization and gave tens of snap detections per second after a threshold detector. The results from the automated detector showed it was necessary to search with the beamformer over a three-dimensional space for reliable performance: (1) arrival time, (2) source range, and (3) array tilt. The results of the beamformer search in array tilt space are consistent with independent acoustic tilt measurements of the same array, showing that snapping shrimp noise in this region can provide valuable inference for the acoustic environment.

}, issn = {0001-4966}, doi = {10.1121/1.5068412}, url = {http://asa.scitation.org/doi/10.1121/1.5068412}, author = {Richards, Edward and Yuan, Zhuqing and Song, Hee-Chun and Hodgkiss, William S.} } @article {53301, title = {Recreational boat traffic effects on fish assemblages: First evidence of detrimental consequences at regulated mooring zones in sensitive marine areas detected by passive acoustics}, journal = {Ocean \& Coastal Management}, volume = {168}, year = {2019}, month = {Jan-02-2019}, pages = {22 - 34}, abstract = {

We assess the impact of recreational boat traffic on sensitive habitats in the Western Mediterranean using passive acoustics. We compared underwater sounds in three regulated mooring locations vs a pristine location; and temporal differences in the pristine location vs the nearest mooring between high and low touristic seasons. We measured the number of pulses/minute, fish pulse patterns, and percentage of boat noise occurrence and its relative average power level. At the pristine location, the call rates and their complexity were significantly higher and the motorboat noise was significantly lower. The temporal trend of biophonic sounds decreased significantly in the pristine location. In contrast, in the mooring sites, the motorboat noise decreased significantly and the fish calls remained at low levels in both seasons. In conclusion, motorboat noise negatively affects the complexity of the fish assemblages but could be conditioned to their historic uses.

}, keywords = {bioacoustics, Croaker, Drummer, Fish assemblage, Mooring, Motorboat noise, passive acoustics}, issn = {09645691}, doi = {10.1016/j.ocecoaman.2018.10.027}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0964569118301972https://api.elsevier.com/content/article/PII:S0964569118301972?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0964569118301972?httpAccept=text/plain}, author = {Gonz{\'a}lez Correa, Jos{\'e} Miguel and Bayle Sempere, Just-Tom{\'a}s and Juanes, Francis and Rodney A. Rountree and Ru{\'\i}z, Juan Francisco and Ramis, Jaime} } @article {53296, title = {Predator-prey interactions in the Southern California Bight}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1921 - 1921}, abstract = {

The Southern California Bight (SCB) is an important foraging area for a variety of cetacean species, including blue whales and beaked whales. However, the interactions of these species with their prey (krill and deep-water squid, respectively) can be very difficult to observe. Moorings combining passive and active acoustics were deployed at two locations in the SCB in two consecutive fall and winter seasons. A High-frequency Acoustic Recording Package sampling at 200 kHz recorded the full range of baleen and beaked whale signals. The active acoustic system on each mooring included two Simrad Wide Band Acoustic Transceivers (WBAT). A bottom-mounted WBAT had an upward looking 70 kHz transducer and the one at 300 m depth had upward looking 70 kHz and 200 kHz transducers. Over the course of four months, blue whale songs and social calls were recorded on both moorings. Beaked whale echolocation clicks were commonly detected on the mooring deployed offshore, with only rare beaked whale encounters on the coastal mooring. Backscatter data indicated overlap in the presence of cetacean predators and their prey. Scattering layer dynamics were dominated by regular diel migration, with differences in scatterer abundance between mooring sites, as well as on 2\–5 day time scales.

}, issn = {0001-4966}, doi = {10.1121/1.5068414}, url = {http://asa.scitation.org/doi/10.1121/1.5068414}, author = {{\v S}irovi{\'c}, Ana and Baumann-Pickering, Simone and Warren, Joseph} } @article {53282, title = {Spatio-temporal modelling of underwater noise related to an arctic exploration drilling program}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1733 - 1733}, abstract = {

One concern related to oil and gas industry activities in the arctic is the potential impact of anthropogenic noise on marine mammals. To gain understanding of the temporal evolution of the acoustic noise footprint from such activities, and to quantify the geographic extent at which sound levels remain within regulatory thresholds for marine mammal injury and behavioral disturbance, this work presents a comprehensive monitoring and modeling study of anthropogenic noise resulting from an exploration drilling project in the northeastern Chukchi Sea, conducted from July to October, 2015. Measured acoustic source levels of multiple vessels and drilling equipment were used to generate time-dependent wide-area noise fields. Model validation was carried out by comparing simulated results with high-resolution acoustic data acquired at multiple stations in the area. The study shows that noise radiating from up to 19 supporting vessels is usually dominant, but noise from certain drilling-related activities occasionally rises above vessel noise within a radius of 8 km from drillsites. Modeled scenarios also show that by constraining vessel positions to within a few kilometers of the drilling location, simultaneous construction of two oil well top holes results in minor increment of the aggregate acoustic footprint\’s extent relative to single-well drilling.

}, issn = {0001-4966}, doi = {10.1121/1.5067686}, url = {http://asa.scitation.org/doi/10.1121/1.5067686}, author = {Quijano, Jorge E. and Hannay, David E. and Melanie E. Austin} } @article {53277, title = {The feasibility of a multipurpose acoustic network in Baffin Bay}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1984 - 1984}, abstract = {

Operating autonomous underwater vehicles at high latitudes is a challenge because ice cover prevents the use of GPS or data communications. As a result, our scientific observations are biased towards late spring, summer, and early autumn when ships can navigate and autonomous platforms can safely surface. To address this problem, we studied the feasibility of a basin-scale multipurpose acoustic network called the \“Baffin Bay Acoustic Navigation and Communication System\” (BBANC). BBANC would deploy broadband low frequency sources and receivers, offering one-way communication, acoustic positioning, and acoustic thermometry services. Passive acoustic listening elements would support the study of marine mammal communication and ambient noise from ships, ocean-based resource exploitation, and ice dynamics, as well as gate acoustic source operation in the presence of marine mammals. We describe the challenges and design parameters for such a system, as well as define additional acoustic and remote sensing measurements required to complete a system design. Drawing from a large database of Baffin Bay hydrography, we present simulations of under-ice sound speed conditions, ice properties derived from satellite remote sensing and upward looking sonar data, and modelled acoustic propagation paths in an ice-covered Baffin Bay. We also assess the feasibility of non-coherent and coherent communication.

}, issn = {0001-4966}, doi = {10.1121/1.5068660}, url = {http://asa.scitation.org/doi/10.1121/1.5068660}, author = {Rehm, Eric and Dushaw, Brian D. and Freitag, Lee E. and Heaney, Kevin D. and Carr, Scott and Dakin, Thomas and Fissel, David and Heard, Garry J.} } @article {53270, title = {Multi-year measurements of the underwater noise field directionality in the shallow Beaufort Sea during open-water and drifting ice flow conditions}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1696 - 1697}, abstract = {

Between 2007 and 2014, over 35 Directional Autonomous Seafloor Acoustic Recorders (DASARs) were deployed over a 280 km swath of the Beaufort Sea continental shelf (20\–55 m depth) during the open-water season, in order to monitor the fall (westward) bowhead whale migration. DASARs have one omnidirectional pressure sensor and two orthogonal particle motion sensors, which permit instantaneous measurements of the azimuths of both transient signals and continuous noise between 20 and 500 Hz. The lack of significant shipping or industrial noise in this region provided a rare opportunity to directly measure the properties of wind-driven noise in expanding ice-free regions. Here, we map the azimuthal directionality of the diffuse Beaufort ambient noise field as a function of frequency and space across seven seasons. The dominant directionality of the diffuse ambient noise field varied strongly with frequency and was highly correlated with the received power spectral density. Certain directional features of the ambient noise field remained stable over seven deployment seasons, suggesting that judicious processing of the ambient noise soundscape could provide underwater navigational information in arctic waters. The influence of local drifting floes and sheets of ice on this directionality is also examined. [Work sponsored by ONR.]

}, issn = {0001-4966}, doi = {10.1121/1.5067541}, url = {http://asa.scitation.org/doi/10.1121/1.5067541}, author = {Thode, Aaron and Blackwell, Susanna B. and Kim, Katherine H. and Alexander S. Conrad} } @article {53025, title = {Acoustic characterization of exploration drilling in the Chukchi and Beaufort seas}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-07-2018}, pages = {115 - 123}, abstract = {

This paper characterizes underwater sound levels produced by three drilling units during offshore exploration drilling at three sites in the Beaufort and Chukchi seas. Received levels and spectra are reported as functions of distance during drilling and excavation of mudline cellars (MLCs). Sound levels emitted during MLC excavation exceeded those during drilling at all three sites, although this operation was much shorter in duration. Drilling sounds exhibited tones below 2\ kHz, with harmonics present to 10\ kHz, while MLC excavation sounds were broadband in character. Drilling sounds varied substantially between the three operations, whereas MLC excavation sounds were more consistent in amplitude and spectral distribution. Estimates of broadband and 1/3-octave band source levels were computed from measurements at 1\ km range. The broadband drilling source levels were 168.6\ dB re 1\ \μPa m for the Kulluk drilling unit, 174.9\ dB re 1\ \μPa m for the drillship Noble Discoverer, and 170.1\ dB re 1\ \μPa m for the semi-submersible Polar Pioneer. The received levels measured at 1\ km during MLC excavation yielded source level estimates that were more consistent among sources: 191.8, 193.0, and 193.3\ dB re 1\ \μPa for the Discoverer, Kulluk, and Polar Pioneer, respectively.

}, issn = {0001-4966}, doi = {10.1121/1.5044417}, url = {http://asa.scitation.org/doi/10.1121/1.5044417}, author = {Hannay, David E. and Br{\"o}ker, Koen C.} }