Ecología trófica de peces demersales en el Golfo San Jorge

Abstract

This work is a first approach in the study of the trophic ecology from a multispecific fishery in San Jorge Gulf (45°-47°S), Argentina. Stomach contents from 28 demersal fish species were analyzed. Taxonomic and trophic spectrum were obtained. Using weight percentage of each prey, trophic spectrum variations for size classes were analized for each of the 12 considered "dominant" species. Overlaping in the diet among these predators was estimate using cluster analysis. There was an interespecific diet overlap between juveniles belonging to demersal-benthic fish species, because all of them prey upon Stomatopoda and Munida. Adults from those species and hake prefered young and adult hake as preys, while Macruronus magellanicus and juvelines Merluccius hubbsi ate mainly zooplankton. In addition, there were son seasonal changes in prey species preferences, but food habits changed considerably with fish size.