Digestión secundaria en el análisis del contenido gástrico del calamar rojo dosidicus gigas (Cephalopoda: Teuthoidea): ¿qué tan importante es?

Abstract

The biological significance of the secondary digestion, i.e., prey of the prey, was determined in the analysis of stomach contents of 112 jumbo squid Dosidicus gigas. Squids were caught on the continental shelf off the coast of central-southern Chile during austral winter and spring 2005. All prey (digested and those from opened stomachs of the prey in the squids) found in the squid stomachs were assessed. The results obtained by using several trophic indices (numeric, gravimetric, frequency of occurrence, relative importance, percentage similarity and trophic heterogeneity), plus the average weight of common prey between seasons (winter and spring) and the Spearman correlation coefficient, revealed no significant differences in the feeding behavior between sexes, ontogenetic and seasonal groups. Comparing the primary with the secondary digestion allow us to conclude that consider or not the latter, in a quantitative point of view, is not relevant in assessing the food preferences squid. On the other hand, the biological significance of secondary digestion from a qualitative point of view may still be relevant when the aim is to avoid overestimating the food spectrum for this species.