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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.

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.

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.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2008

The overall objective of this SBIR proposal is the development of a software-based tool or database known as the Marine Assessment, Decision, and Planning Tool (MADPT) for Protected Species. Knowledge about federally protected species such as fishes, marine mammals, sea turtles, and invertebrates such as corals or abalone is vital for scheduling at-sea activities so that potential impacts to these species can be avoided or minimized. Ready access to pertinent information about a marine species, including its distribution, density, behavior, life history and bioacoustic parameters, environmental stressors, and key habitats is critical for environmental planners, environmental compliance specialists, scientific researchers, and others to make informed, science-based decisions about locating at-sea or marine activities and the potential impacts of those activities on protected species and habitats. This database tool will be designed to provide ready access to the needed scientific information and data on marine species, especially those protected by United States federal regulatory mandates. The first step, or Phase I, of this effort will entail demonstrating the feasibility of developing and generating such a comprehensive database by selecting one taxon of protected species, fishes, upon which to focus the development and later data-population efforts.

Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase II | Award Amount: 500.00K | Year: 2005

Underwater acoustic modeling plays an essential role in the design, development, test, and operation of sonar systems. Active acoustic clutter can increase the sonar false alert rate or equivalently decrease the probability of detection/classification, and is a key issue in the development and utility of active sonar systems. The ability to predict reverberation and clutter is inseparably tied to other modeling tasks, including propagation modeling as well as boundary and volume characterization. The system sonar equation method supports development of a virtual acoustic environment and can be used to produce time series data for examination of the reverberation and clutter influence in the sonar system’s operating parameters. A multi-tiered approach will be used, including: 1) physics-based clutter research (bottom clutter and volume clutter; 2) development of algorithms to generate stochastic realizations of bathymetry and volume scattering features; 3) development of a semi-deterministic reverberation model; 4) development of a module to incorporate stochastic clutter into a deterministic reverberation output; and 5) development of a Parabolic-Equation/Normal-Mode module. The overall objective is to develop and incorporate physics-based reverberation and clutter modeling approaches into current system sonar equation and propagation models used by the sonar designer, planner, and operator.

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