Ecología trófica de la pescadilla de red, Cynoscion guatucupa (Pisces: Sciaenidae), en aguas del Atlántico sudoccidental.
Trophic spectrum of Cynoscion guatucupa (striped weakfish) was analyzed through stomach content of individuals coming from two areas of Buenos Aires coast (38° 30'S - 41° 30'S): Argentine - Uruguayan Fishing Common Zone (AUFCZ) and El Rincón area (Argentine Sea, SW Atlantic). The stomach contents of 3323 individual captured in research cruises carried out during 2004 and 2005 was determined. In the diet 39 prey items were identified corresponding to 4 Phyla. Trophic spectrum was determined with Index of Relative Importance (IRI), where fishes were the principal prey (72,53 percentage IRI), crustaceans were secondary prey (27,44 percentage IRI) and with minor values polychaetes and mollusk (0,2 percentageIRI) were found. Pelagic fish was the predominant food item and Engraulis anchoita (75, 02 percentage IRI) was the most important prey along the year and in both study areas. Other fish item were the horse mackerel (Trachurus lathami, 2,56 percentage IRI) and the anchovy (Anchoa marinii, 0,56 percentage IRI). The crustacean Peisos petrunkevitchi (11,75 percentage IRI) was the most important and in second order Argentine stiletto shrimp (Artemesia longinaris, 0,81 percentage IRI) y Argentine red shrimp langostino (Pleoticus muelleri, 0,51 percentage IRI) were found. There is not any differences in diet of both sexes. C. guatucupa it is a predator specialist in pelagic fish. According to trophic level C. guatucupa was considered tertiary consumer. Significant differences were found when comparing the diet among individuals in both study areas mainly due to the biggest contribution of fish. In AUFCZ the striped weakfish was more ichthyophagus than in the south area, where exhibit mainly a carcinophagus diet in juvenile and ichthyophagus in adult specimens. Trophic niche breadth was narrower in the north area than in the south, similar results were obtained when we discriminate between sexes and sizes too. In the north area overlap diet was determined for all size group meanwhile in the south, there was no overlap between two groups: individual of minor and major size.