Feeding ecology of castaneta (Cheilodactylus bergi; Pisces: Cheilodactylidae) in the south-western Atlantic (34-47 degree S)

Abstract

The feeding ecology of castaneta (Cheilodactylus bergi) was studied during six research cruises carried out both in the Argentine-Uruguayan Common Fishing Zone during 1986-87 and at the southern border of the distribution area of the species during 1988-89. A qualitative and quantitative analysis was made. The trophic spectrum was analysed by fish size class, season and bathymetric depth.

A trend to euryphagy and trophic opportunism was evident. Castaiieta preyed primarily on polychaetes and secondarily on crustaceans. This species showed both seasonal and bathymetric variations in its trophic spectrum. The diet of juveniles was closely related to the pelagic food web (copepods and euphausids), whereas adults consumed benthic organisms (polychaetes, echinoderms and gammarid amphipods). Such a trend was more evident among larger fish.