Journal ArticleDOI
Backscattering cross sections of live fish: PDF and aspect
Kung Huang,Clarence S. Clay +1 more
TLDR
In this article, the probability density function (PDF) of the peaks of the envelopes of sonar echo from live fish were measured at beam aspect and the measurements were made at 220 kHz and in a waveguide.Abstract:
The probability density function (PDF) of the peaks of the envelopes of sonar echo from live fish were measured at beam aspect. The measurements were made at 220 kHz and in a waveguide. The fish was the common shiner (Notropis cornutus) and was about 120 mm (about 18 acoustic wavelengths) long. The PDF of the echoes was approximately Rayleigh when the fish was moving gently. The backscattering cross section equaled 4.2×10−5 m2. Transformation of the PDF’s to a target strength display in decibels displaced the maximum of the PDF to the target strength equaling 10 log10 (σbs/A0)+3 dB where σbs is the mean backscattering cross section and A0=1 m2. The target strengths of the common shiner (120 mm) and the mummechog (Fundulus heteroclitus, 100 mm) were measured as a function of aspect angle. Comparison of the experimental measurements and Love’s empirical target strengths for any aspect showed that the measured target strengths at broadside aspect were about the same and the target strengths at other aspect a...read more
Citations
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Journal ArticleDOI
Sonar echo statistics as a remote-sensing tool: Volume and seafloor
Timothy K. Stanton,C. Clay +1 more
TL;DR: In this paper, a downward-looking sonar and Rice statistics are combined to predict echo fluctuations in terms of rms roughness of the seafloor and correlation area (product of x and y correlation distances).
Journal ArticleDOI
Sonar systems and aquatic organisms: matching equipment and model parameters
John K. Horne,Clarence S. Clay +1 more
TL;DR: In this article, the Kirchhoff-ray mode scattering model was used to quantify fish and zooplankton backscatter as a function of carrier frequency, fish length, and swimbladder aspect.
Journal ArticleDOI
Interpretation of in situ target-strength data
D. N. MacLennan,A. Menz +1 more
TL;DR: In this article, a stochastic method for estimating the constant b in the formula TS=20 log (L)−b, by a least-squares fitting procedure, is presented.
Journal ArticleDOI
Comparison of target strength distributions and fish densities obtained with split and single beam echo sounders
TL;DR: In this paper, the authors compared results from analysis of split-beam and single-beam acoustic surveys using two data sets, one from the Baltic Sea (both systems at 70 kHz) and one from Lake Erie (70 kHz single beam, 70 and 120 kHz split beam).
Book ChapterDOI
Active and Passive Acoustics to Locate and Study Fish
TL;DR: Active and passive acoustics have been used to detect and enumerate fishes and to define where the fish are to be found as mentioned in this paper, which is a challenge in the field of aquatic biology.