Trophic ecology of the demersal predator Brazilian flathead Percophis brasiliensis (Percophidae) in a coastal upwelling ecosystem, SW Atlantic

Abstract

Upwellings are important oceanographic processes that induce several changes in marine ecosystems, including in the benthic-pelagic coupling (BPC) that plays a major role in coastal areas. However, there is little available information about the possible effects of coastal upwellings on the trophic role of predators and in the BPC. Thus, here we investigate possible seasonal and ontogenetic changes in the trophic interaction of a demersal predator, the Brazilian flathead Percophis brasiliensis, from an upwelling ecosystem. Sampling was carried out for one year during two coastal upwelling events. Based on stomach content analysis (SCA) were recorded seasonal diet shifts, probably driven by coastal upwellings, leading to an increase in pelagic prey and changing the trophic coupling pathways. Stable isotope analysis revealed that isotopic niche decreased with the body size, as well as the values of the Levins’ index. Also, significant, and positive relationships were observed between δ13C and δ15N versus total length. Our results showed that the demersal predator has a relevant trophic role in the BPC which is probably influenced by coastal upwellings.

Keywords:
Benthic-pelagic coupling; Feeding habit; Marine ecology; Stable isotopes; Stomach content