Índices ponderados de abundancia relativa, obtenidos a partir de modelos lineales generalizados, considerando la presencia de valores nulos de captura.

Abstract

General Linear Models (GLM) and generalized linear models (GLMs), that allow to integrate in a simple way the different factors that influence catch per unit of effort (CPUE) variation, are used to estimate annual abundance indices. The effect associated to the Year factor is considered and, based on the results obtained, the index is built. Nevertheless, when significant interactions that include said factor occur, the result is indices proportional to the mean annual abundance of each year with proportion coefficients that depend on the year, which does not allow to compare the series terms. In this paper the weighted abundance indices obtained with the GLM and GLMs are established and how to define the population mean annual density as a function of the parameters of the models used is considered. An application example with null CPUE values in patagonian smoothhound is shown and debate on the correct selection of the fleet to provide the data used to estimate annual weighted abundance indices presented.