New broadband methods for resonance classification and high-resolution imagery of fish with swimbladders using a modified commercial broadband echosounder
Stanton, Timothy K.
Jech, J. Michael
Irish, James D.
MetadataShow full item record
A commercial acoustic system, originally designed for seafloor applications, has been adapted for studying fish with swimbladders. The towed system contains broadband acoustic channels collectively spanning the frequency range 1.7–100 kHz, with some gaps. Using a pulse-compression technique, the range resolution of the echoes is ~20 and 3 cm in the lower and upper ranges of the frequencies, respectively, allowing high-resolution imaging of patches and resolving fish near the seafloor. Measuring the swimbladder resonance at the lower frequencies eliminates major ambiguities normally associated with the interpretation of fish echo data: (i) the resonance frequency can be used to estimate the volume of the swimbladder (inferring the size of fish), and (ii) signals at the lower frequencies do not depend strongly on the orientation of the fish. At-sea studies of Atlantic herring demonstrate the potential for routine measurements of fish size and density, with significant improvements in accuracy over traditional high-frequency narrowband echosounders. The system also detected patches of scatterers, presumably zooplankton, at the higher frequencies. New techniques for quantitative use of broadband systems are presented, including broadband calibration and relating target strength and volume-scattering strength to quantities associated with broadband signal processing.
© 2010 The Authors. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial License. The definitive version was published in ICES Journal of Marine Science: Journal du Conseil 67 (2010): 365-378, doi:10.1093/icesjms/fsp262.
The following license files are associated with this item:
Except where otherwise noted, this item's license is described as Attribution-NonCommercial 2.5 UK: England & Wales
Showing items related by title, author, creator and subject.
Resonance classification of mixed assemblages of fish with swimbladders using a modified commercial broadband acoustic echosounder at 1–6 kHz Stanton, Timothy K.; Sellers, Cynthia J.; Jech, J. Michael (NRC Research Press, 2012-04-19)Recently developed broadband acoustic methods were used to study mixed assemblages of fish spanning a wide range of lengths and species. Through a combination of resonance classification and pulse-compression signal ...
Lvov, Yuri V.; Polzin, Kurt L.; Yokoyama, Naoto (American Meteorological Society, 2012-05)The spectral energy density of the internal waves in the open ocean is considered. The Garrett and Munk spectrum and the resonant kinetic equation are used as the main tools of the study. Evaluations of a resonant kinetic ...
Annual and semiannual cycle of equatorial Atlantic circulation associated with basin-mode resonance Brandt, Peter; Claus, Martin; Greatbatch, Richard; Kopte, Robert; Toole, John M.; Johns, William E.; Böning, Claus W. (American Meteorological Society, 2016-10-05)Seasonal variability of the tropical Atlantic circulation is dominated by the annual cycle, but semiannual variability is also pronounced, despite weak forcing at that period. This study uses multiyear, full-depth velocity ...