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Ellison W.T.,Marine Acoustics Inc. | Southall B.L.,Southall Environmental Associates Inc. | Southall B.L.,University of California at Santa Cruz | Clark C.W.,Cornell University | Frankel A.S.,Marine Acoustics Inc.
Conservation Biology | Year: 2012

Acute effects of anthropogenic sounds on marine mammals, such as from military sonars, energy development, and offshore construction, have received considerable international attention from scientists, regulators, and industry. Moreover, there has been increasing recognition and concern about the potential chronic effects of human activities (e.g., shipping). It has been demonstrated that increases in human activity and background noise can alter habitats of marine animals and potentially mask communications for species that rely on sound to mate, feed, avoid predators, and navigate. Without exception, regulatory agencies required to assess and manage the effects of noise on marine mammals have addressed only the acute effects of noise on hearing and behavior. Furthermore, they have relied on a single exposure metric to assess acute effects: the absolute sound level received by the animal. There is compelling evidence that factors other than received sound level, including the activity state of animals exposed to different sounds, the nature and novelty of a sound, and spatial relations between sound source and receiving animals (i.e., the exposure context) strongly affect the probability of a behavioral response. A more comprehensive assessment method is needed that accounts for the fact that multiple contextual factors can affect how animals respond to both acute and chronic noise. We propose a three-part approach. The first includes measurement and evaluation of context-based behavioral responses of marine mammals exposed to various sounds. The second includes new assessment metrics that emphasize relative sound levels (i.e., ratio of signal to background noise and level above hearing threshold). The third considers the effects of chronic and acute noise exposure. All three aspects of sound exposure (context, relative sound level, and chronic noise) mediate behavioral response, and we suggest they be integrated into ecosystem-level management and the spatial planning of human offshore activities. © 2011 Society for Conservation Biology.


PubMed | BP Exploration Alaska Inc., College of William and Mary, Cornell University, National Oceanic and Atmospheric Administration and 6 more.
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

There are no standards for assessment of the cumulative effects of underwater sound. Quantitative assessments typically consider a single source, whereas qualitative assessments may include multiple sources but rarely identify response variables. As a step toward understanding the cumulative effects of underwater sound, we assessed the aggregated sounds of multiple sources received by migrating bowhead whales (Balaena mysticetus). The quantitative method models the sound field from multiple sources and simulates movement of a population through it. The qualitative method uses experts to assess the responses of individuals and populations to sound sources and identify the potential mechanisms. These methods increase the transparency of assessments.


PubMed | Marine Acoustics Inc. and Southall Environmental Associates Inc.
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

The effect of anthropogenic sounds on marine wildlife is typically assessed by convolving the spatial, temporal, and spectral properties of a modeled sound field with a representation of animal distribution within the field. Both components benefit from stochastic modeling techniques based on field observations. Recent studies have also highlighted the effect of context on the probability and severity of the animal behavioral response to sound. This paper extends the stochastic approach to three modeling scenarios, including key contextual variables in aversion from a given level of sound and as a means of evaluating the effectiveness of passive acoustic monitoring.


Halvorsen M.B.,University of Maryland University College | Halvorsen M.B.,Pacific Northwest National Laboratory | Zeddies D.G.,University of Maryland University College | Ellison W.T.,Marine Acoustics Inc. | And 2 more authors.
Journal of the Acoustical Society of America | Year: 2012

Caged fish were exposed to sound from mid-frequency active (MFA) transducers in a 5 5 planar array which simulated MFA sounds at received sound pressure levels of 210 dB SPL(re 1 Pa). The exposure sound consisted of a 2 s frequency sweep from 2.8 to 3.8 kHz followed by a 1 s tone at 3.3 kHz. The sound sequence was repeated every 25 s for five repetitions resulting in a cumulative sound exposure level (SEL cum) of 220 dB re 1 Pa 2 s. The cumulative exposure level did not affect the hearing sensitivity of rainbow trout, a species whose hearing range is lower than the frequencies in the presented MFA sound. In contrast, one cohort of channel catfish showed a statistically significant temporary threshold shift of 4-6 dB at 2300 Hz, but not at lower tested frequencies, whereas a second cohort showed no change. It is likely that this threshold shift resulted from the frequency spectrum of the MFA sound overlapping with the upper end of the hearing frequency range of the channel catfish. The observed threshold shifts in channel catfish recovered within 24 h. There was no mortality associated with the MFA sound exposure used in this test. © 2012 Acoustical Society of America.


Hatch L.T.,National Oceanic and Atmospheric Administration | Clark C.W.,Cornell University | Van Parijs S.M.,National Oceanic and Atmospheric Administration | Frankel A.S.,Marine Acoustics Inc. | Ponirakis D.W.,Cornell University
Conservation Biology | Year: 2012

The effects of chronic exposure to increasing levels of human-induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human-induced sound on contact-calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (∼10,000 km2) and time period (peak feeding time). We used an array of temporary, bottom-mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel-tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal-to-noise ratio and the assumed recognition differential) for contact-calling right whales was negative (-1 dB) under current ambient noise levels and was further reduced (-2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63-67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10-min period. These results highlight the limitations of exposure-threshold (i.e., dose-response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide-ranging noise effects in emerging ocean-planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. ©2012 Society for Conservation Biology.


Vigness-Raposa K.J.,University of Rhode Island | Vigness-Raposa K.J.,Marine Acoustics Inc. | Kenney R.D.,University of Rhode Island | Gonzalez M.L.,University of Rhode Island | August P.V.,University of Rhode Island
Marine Mammal Science | Year: 2010

Understanding the population structure of a species is critical to its effective management and conservation. The humpback whale (Megaptera novaeangliae) has been the target of numerous research projects in several ocean basins, but no clear picture of its population structure has emerged. In the North Atlantic Ocean, genetic analyses and photo-identification movements have shown significant heterogeneity among the summer feeding grounds. Building on this knowledge, we test the hypothesis that the feeding grounds represent distinct populations by analyzing the spatial pattern of summer humpback whale sightings and survey effort. Controlling for the spatial pattern of effort, sightings are clustered, with peaks at radial distances of 300 km, 600 km, and 1,500 km. These results provide insight into the spatial extent of the summer population structure of humpback whales in the North Atlantic Ocean. Fine-scale clustering at distances of 300 km and 600 km is compatible with multiple populations consisting of the Gulf of Maine, eastern Canada, western Greenland, and Iceland. Broad-scale clustering at distances of 1,500 km may represent divisions between the western and eastern North Atlantic populations. These results provide spatial bounds to the feeding grounds of humpback whales and emphasize their distinct nature as management units. © 2009 by the Society for Marine Mammalogy.


Risch D.,Integrated Statistics | Corkeron P.J.,Northeast Fisheries Science Center | Ellison W.T.,Marine Acoustics Inc. | van Parijs S.M.,Northeast Fisheries Science Center
PLoS ONE | Year: 2012

The effect of underwater anthropogenic sound on marine mammals is of increasing concern. Here we show that humpback whale (Megaptera novaeangliae) song in the Stellwagen Bank National Marine Sanctuary (SBNMS) was reduced, concurrent with transmissions of an Ocean Acoustic Waveguide Remote Sensing (OAWRS) experiment approximately 200 km away. We detected the OAWRS experiment in SBNMS during an 11 day period in autumn 2006. We compared the occurrence of song for 11 days before, during and after the experiment with song over the same 33 calendar days in two later years. Using a quasi-Poisson generalized linear model (GLM), we demonstrate a significant difference in the number of minutes with detected song between periods and years. The lack of humpback whale song during the OAWRS experiment was the most substantial signal in the data. Our findings demonstrate the greatest published distance over which anthropogenic sound has been shown to affect vocalizing baleen whales, and the first time that active acoustic fisheries technology has been shown to have this effect. The suitability of Ocean Acoustic Waveguide Remote Sensing technology for in-situ, long term monitoring of marine ecosystems should be considered, bearing in mind its possible effects on non-target species, in particular protected species.


Frankel A.S.,Marine Acoustics Inc. | Zeddies D.,Marine Acoustics Inc. | Simard P.,University of South Florida | Mann D.,University of South Florida
Journal of the Acoustical Society of America | Year: 2014

Whistles of bottlenose dolphins (Tursiops truncatus) and Atlantic spotted dolphins (Stenella frontalis) in the eastern Gulf of Mexico were recorded and measured with a calibrated towed hydrophone array. Surveys encountered groups of both bottlenose (N = 10) and spotted dolphins (N = 5). Analysis of those data produced 1695 bottlenose dolphin whistles and 1273 spotted dolphin whistles with a high signal-to-noise ratio. Whistle frequency metrics were lower in bottlenose than spotted dolphins, while whistle duration was longer in spotted dolphins, data that may help inform automatic classification algorithms. Source levels were estimated by determining the range and bearing of an individual dolphin from the array and then adding the predicted transmission loss to the calculated received level. The median bottlenose dolphin source level was 138 dB re 1μPa at 1 m with a range of 114-163 dB re 1μPa at 1 m. The median spotted dolphin source level was 138 dB re 1μPa at 1 m with a range of 115-163 dB re 1μPa at 1 m. These source level measurements, in conjunction with estimates of vocalization rates and transmission loss models, can be used to improve passive acoustically determined dolphin abundance estimates in the Gulf of Mexico. © 2014 Acoustical Society of America.


Zeddies D.G.,Marine Acoustics Inc. | Fay R.R.,Loyola University Chicago | Alderks P.W.,University of Washington | Shaub K.S.,University of Washington | Sisneros J.A.,University of Washington
Journal of the Acoustical Society of America | Year: 2010

The aim of this study was to use plainfin midshipman fish (Porichthys notatus) as a general model to explore how fishes localize an underwater sound source in the relatively simple geometry of a monopole sound field. The robust phonotaxic responses displayed by gravid females toward a monopole sound projector (J-9) broadcasting a low-frequency (90 Hz) tone similar to the fundamental frequency of the males advertisement call were examined. The projectors sound field was mapped at 5 cm resolution azimuth using an eight-hydrophone array. Acoustic pressure was measured with the array and acoustic particle motion was calculated from pressure gradients between hydrophones. The response pathways of the fish were analyzed from video recordings and compared to the sound field. Gravid females at initial release were directed toward the sound source, and the majority (73%) swam to the playback projector with straight to slightly curved tracks in the direction of the source and in line with local particle motion vectors. In contrast, the initial direction of the control (sound-off) group did not differ from random. This paper reports on a comparison of fish localization behavior with directional cues available in the form of local particle motion vectors. © 2010 Acoustical Society of America.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.58K | Year: 2015

The opportunity of interest is the introduction and application of a bistatic tool set for both surface and submarine Mid-Frequency (MF) active sonar systems to enhance anti-submarine warfare (ASW) capability in strike group or coordinated surface and submarine ASW operations. The ability to localize threat submarine forces in a battlefield scenario by judicious application of bistatic capability in both surface ship and submarine sonar systems provides important performance benefits to the ASW kill chain. Such leveraging provides a significantly increased ASW capability beyond simple additive value. Achieving these capabilities requires a clear understanding of the information exchange hurdles that must be undertaken at each stage of the process from design and implementation of the underlying search concept to critical bistatic timing, orientation and localization information. An algorithmic approach to a parametric evaluation of these critical parameters will be developed. A principle evaluation metric of the algorithm will be the resultant bistatic detection Area of Uncertainty (AOU), a value to be determined at each step of the parametric approach. As bistatic capabilities are developed and implemented, the capability can be efficiently and rapidly transitioned among ASW sonar systems via the common processing development of the AxB process.

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