Minimising errors in estimating fish population and biomass densities using the ‘acoustic volume backscattering strength’ method
Open Access
- 1 March 1987
- journal article
- research article
- Published by Taylor & Francis in New Zealand Journal of Marine and Freshwater Research
- Vol. 21 (1) , 99-108
- https://doi.org/10.1080/00288330.1987.9516204
Abstract
The basic acoustical methods for estimating the volume backscattering strength and the absolute biomass density are commonly known. However, the detailed techniques for minimising errors in fitting the calibrated parameters of an echo sounding system in these computations are still not adequately examined and discussed. This paper describes and discusses the following computing techniques involved in the absolute biomass estimation: (i) the fitting of the calibrated time varied gain (TVG) curve, the selection of its operating interval, and the correction of its response; (ii) the compensation for the limitation of the signal bandwidth; (iii) the computation of the equivalent beam width of a transducer using its calibrated beam patterns; and (iv) the accuracy in the conversion from the volume backscattering to the absolute fish density using individual fish target strength measurements.Keywords
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