Applying an alternative method of echo-integration

Abstract Estimators of mean Echo Value Constant (the ratio between echo abundance and the number of fish) in an alternative echo-integrating method were tried with the SIMRAD EK 60 split-beam echosounder. The mean fish-density estimates of NE Arctic cod were compared with corresponding estimates by...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Author: Aksland, Magnar
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2006
Subjects:
Ecology
Aquatic Science
Ecology, Evolution, Behavior and Systematics
Oceanography
Arctic
Arctic cod
Online Access:http://dx.doi.org/10.1016/j.icesjms.2006.03.027
http://academic.oup.com/icesjms/article-pdf/63/8/1438/29125615/63-8-1438.pdf
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Summary:Abstract Estimators of mean Echo Value Constant (the ratio between echo abundance and the number of fish) in an alternative echo-integrating method were tried with the SIMRAD EK 60 split-beam echosounder. The mean fish-density estimates of NE Arctic cod were compared with corresponding estimates by the classical echo-integration method; the two methods gave similar results. The alternative method uses integrated single-fish echoes, and a new algorithm to extract and integrate single-target echoes is introduced and used. This algorithm uses echo shape and angle stability, not echo amplitude, to test for the presence of single-target echoes. Apparent single-target echoes with a dynamic range of 60 dB in integrated echo intensity were extracted.

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