摘要 :
The objectives of this study were as follows: to describe the condition of the swimbladder in the abundant species of the collection, including measurements where feasible, and to determine the effect of formaldehyde preservation ...
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The objectives of this study were as follows: to describe the condition of the swimbladder in the abundant species of the collection, including measurements where feasible, and to determine the effect of formaldehyde preservation on the swimbladder.
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摘要 :
Long-Term Goals: To understand and exploit the resonance scattering by swimbladder-bearing fish (typically in the 1-10 kHz frequency region). Exploitation of the resonances can significantly reduce ambiguities in interpreting acou...
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Long-Term Goals: To understand and exploit the resonance scattering by swimbladder-bearing fish (typically in the 1-10 kHz frequency region). Exploitation of the resonances can significantly reduce ambiguities in interpreting acoustic scattering in terms of meaningful biological parameters compared with traditional higher frequency approaches and other lower frequency narrowband approaches. Objectives: To conduct a new class of quantitative acoustic studies of scattering by swimbladder-bearing fish utilizing new broadband-acoustic technology that is optimized for use in the resonance scattering region of fish.
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摘要 :
Long-term Goals: To accurately describe the spatial and temporal distributions of fish and to quantify the mid-frequency clutter characteristics of fish. Objectives: To conduct a new class of quantitative acoustic studies of scatt...
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Long-term Goals: To accurately describe the spatial and temporal distributions of fish and to quantify the mid-frequency clutter characteristics of fish. Objectives: To conduct a new class of quantitative acoustic studies of scattering by swimbladder-bearing fish utilizing new broadband-acoustic technology that is optimized for use in the resonance scattering region of fish. The studies, which include use of long-range horizontal-looking and short- range downward-looking systems, exploit the resonance scattering of the fish to significantly reduce ambiguities in interpretation of echo data.
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摘要 :
Demonstrate the potential of bioacoustic absorption spectroscopy for tomographic mapping of the bioacoustic parameters of fish with swim bladders in shallow water.
摘要 :
To understand and exploit acoustic reverberation by and transmission through fish and related acoustic signal processing. The focus will be on swimbladder-bearing fish with resonance frequencies in the 100's of Hz to low kHz.
摘要 :
To understand and exploit the resonance scattering by swimbladder- bearing fish (typically in the 1-10 kHz frequency region). Exploitation of the resonances can significantly reduce ambiguities in interpreting acoustic scattering ...
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To understand and exploit the resonance scattering by swimbladder- bearing fish (typically in the 1-10 kHz frequency region). Exploitation of the resonances can significantly reduce ambiguities in interpreting acoustic scattering in terms of meaningful biological parameters compared with traditional higher frequency approaches. To conduct a new class of quantitative acoustic studies of scattering by swimbladder-bearing fish utilizing new commercial broadband-acoustic technology that is optimized for use in the resonance scattering region of fish. This research is taking advantage of a commercial system that was originally designed for marine geological and gas/oil exploration. It is especially attractive for use in studying swimbladder-bearing fish because this system was optimized for use in the frequency band in which swimbladders typically resonate. The off-the-shelf sensors on the system (in particular, the transmitters and receivers) were selected and configured in a manner best suited for the fish application. The system is being used for studying distributions of fish in their natural habitat. The research is part of a NOAA/NMFS fisheries study and includes trawling for ground truthing and traditional high frequency echo sounders for comparison. Data are being interpreted in terms of physics-based scattering models whose parameters may be determined empirically as a result of the measurements. Tim Stanton oversees the entire program and is involved in every aspect. Dezhang Chu participated in finalizing system specifications, conducting the system calibration, participating in the at-sea study, and processing the data. Mike Jech conducts the biological sampling, performs high frequency acoustic surveys, and is involved in the design and execution of the cruises.
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摘要 :
The mesopelagic animals which are most often detected acoustically are those which contain gas bubbles within their bodies. In the waters off the Oregon coast, the most abundant animals which contain gas bubbles are myctophids. Bo...
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The mesopelagic animals which are most often detected acoustically are those which contain gas bubbles within their bodies. In the waters off the Oregon coast, the most abundant animals which contain gas bubbles are myctophids. Both the size and the shape of the bubble are important to acoustic measurements. This report summarizes the available information on the acoustically important characteristics of the most abundant myctophids: Stenobrachius leucopsarus, Diaphis theta, Tarletonbeania crenularis, and Protomyctophum thompsoni and crockeri. (Author)
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摘要 :
This report contains information on the FY15 final year personnel, activities, accomplishments, and publications, of this project, which was part of the ONR Fish Acoustics Basic Research Challenge.
摘要 :
To understand and exploit acoustic reverberation by and transmission through fish and related acoustic signal processing. The focus will be on swimbladder-bearing fish with resonance frequencies in the 100's of Hz to low kHz.
摘要 :
The goal is the development of a time-domain acoustical method for investigating the spatial and temporal stochastic variations in fish density within fish schools, and thereby study the statistical fluctuations in the scattering ...
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The goal is the development of a time-domain acoustical method for investigating the spatial and temporal stochastic variations in fish density within fish schools, and thereby study the statistical fluctuations in the scattering of sound from these objects. The objective of this research is to develop a complete time-domain theory of acoustic scattering from, and propagation through, schools of swim bladder fish at and near the swim bladder resonance frequency, including multiple scattering and coherent interaction effects between the individual fish. This should then lead to a prescriptive capability for modeling the evolution of sound pulses as they are scattered from, and pass through, fish schools. Subsequently, it should be possible to identify discrete segments of the signal with different sections of the fish school, and enable an enhanced understanding of signal scattering, and extinction, by the school, and the fluctuations in these properties.
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