Long-range acoustic imaging of the Continental Shelf Environment reveals massive fish schools: 2003 Main Acoustic Clutter Experiment

Results from the three-ship, April–May 2003 Main Acoustics Experiment of the ONR Acoustics Clutter Program are presented. A long-range bistatic sonar system was used to image extensive clutter over wide areas of the New Jersey Continental Shelf in the low- to mid-frequency range in near real-time. A...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2003-10, Vol.114 (4_Supplement), p.2375-2375
Main Authors: Makris, Nicholas C., Ratilal, Purnima, Lai, Yisan, Lee, Sunwoong, Symonds, Deanelle T., Ruhlmann, Lilimar A., Nero, Redwood W., Preston, John R., Scheer, Edward K., Sundvik, Michael T.
Format: Article
Language:English
Subjects:
Marine
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Summary:Results from the three-ship, April–May 2003 Main Acoustics Experiment of the ONR Acoustics Clutter Program are presented. A long-range bistatic sonar system was used to image extensive clutter over wide areas of the New Jersey Continental Shelf in the low- to mid-frequency range in near real-time. A downward-directed high-frequency fish-finding sonar was also simultaneously operated from one of the ships to determine whether fish schools occur in the location of the clutter events. Tracks of the long-range sonar were repeated over days throughout the experiment. Most of the clutter features were observed to evolve both in time and in space moving throughout the survey area and therefore do not consistently correlate with static geologic features. The clutter features were observed to cluster, disperse, and gradually disappear and then re-emerge in the general vicinity at later times. The long-range active sonar data show that the primary source of clutter corresponds to objects moving in the waveguide. This was made certain by our ability to accurately register a number of fixed point targets deployed as controls throughout the experiment. The preliminary finding of this experiment is that the dominant source of clutter in this Continental Shelf environment is marine life, particularly fish schools.
ISSN:0001-4966
1520-8524
DOI:10.1121/1.4777410