Simple relationships expressing dependence of sampling relative error in biomass estimate (by means of a survey) on statistical characteristics of fish concentration density field under examination and on parameters of survey itself, have been derived with the help of mathematical statistics and methods of calculus of probabilities; biomass estimate is determined as a product of average density for region under examination and area of this region. As to hydroacoustic survey, anisotropy parameter, correlation radius along transects and variation coefficient serve as field characteristics on which error depends, and direction of survey with respect to the axis of the correlation ellipse and frequency of transects (sections) serve as survey parameters. Dependences offered here, can be used in practice both for a posteriori estimation of error made when calculating biomass, and for survey planning on the basis of a priori estimates of statistical characteristics of concentration density field. They might make a basis for the procedure of survey operative control.
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