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Middletown, RI, United States

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. Source

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. Source

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. Source

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. Source

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 70.00K | Year: 2008

Existing OAML-approved active acoustic models are under continuous evolution to take advantage of new theoretical and numerical developments and more powerful computational resources. These models are supported by OAML-approved environmental databases that are also constantly updated to accommodate the newly developed models and recent measurements throughout the world. The databases that describe the bottom include the Digital Bathymetric Data Base (DBDBV) multi-resolution bathymetric databases, the Low-Frequency Bottom Loss (LFBL) database, the Bottom Sediment Type (BST) database, and the Bottom Backscattering Strength (BBS) database. Recent physics based research on coupled scattering mechanisms and physics-based clutter as functions of the bottom’s geoacoustic parameters and bathymetry have offered the opportunity for a wholly new approach to developing a prototype generalized bottom database. This approach is based on understanding and describing the underlying physical mechanisms of reverberation and clutter (including bistatic geometries), and provides the ability to harness and integrate the information from the existing databases and new measurement techniques into a generalized bottom database. This database would furnish physics-based and/or empirical bottom parameters to model undersea acoustic propagation, deterministic bottom reverberation and stochastic clutter for emulation of false alarms.

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