Feeding habits of Dosidicus gigas (D'Orbigny, 1835) (Cephalopoda: Teuthoidea) in the central-south coast off Chile

A study on the feeding habits of the jumbo squid Dosidicus gigas (D'Orbigny, 1835) was carried out during the winter season 2005, in waters of the Chilean central and southern Pacific. A total of 52 jumbo squid stomachs from the fishing of the continental slope were collected and examined, in the Eighth and Ninth regions, between 36 degrees 40' S and 38 degrees 55'S, at an average depth of 290 m. To determine the trophic spectrum, the feeding preferences and the importance of the sex and ontogenctic condition in the diet, the numeric, gravimetric, frequency of occurrence methods, and the index of relative importance and dietary similarity were utilized. The frequency of the prey did not vary with relation to the sex and ontogenetic conditions, and was besides a hight trophic similarity in such analysis. The results showed that the diet of D. gigas consist predominatly of fishes and secondly of Mollusca (to include the cannibalism) and crustacean; suggesting that D. gigas is an oportunistic predator of third trophic level. We discuss the reasons and implications of such behavior.