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Latin american journal of aquatic research

On-line version ISSN 0718-560X

Abstract

CANALES, Cristian  and  ARANA, Patricio. Performance of two sampling designs used to evaluate demersal crustaceans with the swept area method. Lat. Am. J. Aquat. Res. [online]. 2009, vol.37, n.2, pp.211-219. ISSN 0718-560X.

Herein, we simulate the theoretical density of the variable catch per unit area (CPUA) for demurral crustaceans distributed over the continental shelf in a pre-determined geographic location. This density was used to simulate two sampling designs traditionally used in Chile for evaluating crustaceans with the swept area method. The performances of systematic and stratified random samplings were evaluated considering different scenarios in terms of the number of strata, transects, and the number of hauls per transect or stratum. As an indicator of efficiency, we measured the mean squared error and the relative error of the estimator of average density. The results indicate that, for a resource that is aggregated in space, is correlated spatially, and has important density gradients, the systematic sampling design presents lower indices of error than does the stratified sampling design.

Keywords : biomass determination; simulation; swept area method; systematic sampling; stratified sampling; demersal resources.

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