Minimising errors in estimating fish population and biomass densities using the ‘acoustic volume backscattering strength’ method
作者:
M. A. Do,
期刊:
New Zealand Journal of Marine and Freshwater Research
(Taylor Available online 1987)
卷期:
Volume 21,
issue 1
页码: 99-108
ISSN:0028-8330
年代: 1987
DOI:10.1080/00288330.1987.9516204
出版商: Taylor & Francis Group
关键词: mean volume backscattering strength;fish population density;fish biomass density;TVG;bandwidth;equivalent beam width;calibration
数据来源: Taylor
摘要:
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.
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