Models
to Measures
The KRM model
was developed independent of any empirical measurements. When completed,
the model was verified using two independent data sets. In the left
panel, maximum backscatter observations at 38 kHz from Nakken and
Olsen (1977) were compared to backscatter predictions from five
Atlantic cod scaled from 8 to 96 cm. On the right panel Jech et
al. (1995) compared KRM backscatter model predictions to empirical
target strength measurements of threadfin shad (Dorosoma petenense)
at 120 kHz (squares), 200 kHz (circles), and 420 kHz (triangles).
In both cases the data fit the independent model predictions well.
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Other KRM
backscatter models have been compared to empirical measures
(not all are published). Predicted target strengths of a group
of 15 lavnun were compared to measurements of 8 tethered fish
at 120 kHz. The plot to the left shows the mean and standard
deviation of target strength plotted as a function of fish length.
The set of points below the line are the overall mean target
strength values for each of the 8 fish. |
The
upper set of points are the mean values for each fish with a
minimum target strength of -50 dB. The original target strength
frequency distributions were bimodally distributed. A threshold
filter of -50 dB removes the small target strengths due to extreme
tilt angles of the fish while tethered. |
Cited References |
Jech,
J.M., Schael, D.M. and Clay, C.S. 1995. Application of three
sound |
|
scattering models to threadfin shad (Dorosoma petenense).
J. Acoust. Soc. Am. 98: 2262-2269. |
Nakken,
O. and Olsen, K. 1977. Target strength measurements of fish.
Rapp. |
|
P.-v. Réun. Cons. Int. Explor. Mer 170: 52-69. |
Horne,
J.K., P.D. Walline, and J.M. Jech. 2000. Comparing acoustic
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model predictions to in situ backscatter measurements
of fish with dual-chambered swimbladders. Journal of Fish Biology
(in press). |
Haro,
A., J. Horne, D. Degan, B. Kulik, and J. Boubee. 1999. An Investigtion
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of
the Feasibility of Employing Hydroacoustic Monitoring as a Means
to Detect the Presence and Movement of Large, Adult Eels (Genus
Anguilla). CARFC Internal Report No. 99-01. |
©2010 Fisheries Acoustics Research
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