A GENERALIZED INDEX FOR STOMACH CONTENTS ANALYSIS IN FISH

Because the most commonly used measures of prey quantity employed in f ish dietary studies have limitations, each emphasising different aspec ts of the diet, several authors have preferred the use of compound ind ices for the purposes of prey ranking. However, the indices described so far are very heterogeneous and produce results that are rather diff icult to compare. In this paper, a generalised index is described whic h is based on vector geometry, and can be used with any number, type a nd combination of percentual parameters. A method for the graphic pres entation and interpretation of the results produced by stomach content analyses is also presented.