New Zealand Journal of Marine and Freshwater Research abstracts

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DIGITAL SYSTEM FOR RECORDING FISH ECHOES

R. F. Coombs

Fisheries Research Division, Ministry of Agriculture and Fisheries, P.O. Box 19-062, Wellington, New Zealand

Abstract A system to record digitised echo information from echo sounders has been developed as part of a project to improve methods of estimating the abundance of fish stocks around New Zealand. The depth of echoes appearing at the echo-sounder receiver is determined, followed by a sequence of samples of the echo envelope defining its shape. All data are digitised and recorded on a seven-track digital magnetic tape recorder. The system is designed to preserve as much information about the echoes as possible. In contrast to other published systems designed to either "count" or "integrate" fish echoes, this system allows free choice of methods of analysis.

N.Z. Journal of Marine and Freshwater Research 11 (3) : 479-88
Received 28 June 1976; revision received 18 March 1977. Fisheries Research Division Publication 315.

PDF file of entire paper: medium quality (590K); (scanned from paper original: notes about this process)

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