CARACTERIZACIÓN ESTACIONAL DE LA DIETA Y PERFIL DE ÁCIDOS GRASOS DE JUVENILES DE Paralichthys orbignyanus (Jenyns, 1842)

Abstract

Knowledge on species diet composition and their seasonal variations, contributes to the understanding of trophic interactions and the role that the species play in the ecosystem. The refuge and high food availability found in estuaries, turn them into nursery areas for many aquatic animals. The aim of this study was to characterize the diet of Paralichthys orbignyanus juveniles and their seasonal variations along a year, assessed by stomach contents and lipid biomarkers. Juvenile flatfish were collected every two months throughout a year (n=78). Diet of P. orbignyanus was mainly composed of polychaetes and misidiaceans. Although there were no significant differences in diets among the seasons (p>0.05), a correspondence analysis showed a dominance of polychaetes consumption in May and misidiaceans in November. A temporal diet segregation in almost all seasons was observed through the analysis of muscle fatty acid profiles, suggesting that they were strongly affected by the seasonal variations of the prey fatty acids. The study of prey fatty acid profiles would provide accurate quantitative estimations of the fish diet using biochemical markers, visualizing which prey is being assimilated and allowing the detection of soft prey which are difficult to identify through stomach content analysis.