Trophic ecology of hairy conger Bassanago albescens in the Southwest Atlantic and its implications for the ecosystem-based fishery management

Abstract

This study aimed to determine the diet composition and feeding strategies of thehairy conger eel Bassanago albescensin the Southwest Atlantic (35° S-45° S), from stomach con-tents analysis of 222 specimens. The diet consisted mainly of cephalopods, followed by isopods,amphipods, ophiuroids, brachyurous and polychaetes. Results showed significant differences in thecomposition of the diet between sexes, regions and size classes that were reflected in the changesin the foraging strategy. The consumption of squid Illex argentinusprogressively increased with agrowing predator size, where the largest individuals showed specialization in the consumption ofthis particular prey. We propose these dietary changes would be related to morphological limita-tions and abilities associated with the body size of B. albescens, with larger individuals havingaccess to larger prey. Our results help to understand the biology of a species that has a sympatricdistribution with two key species in the Argentine fisheries: hake Merluccius hubbsi and I. argenti-nus, with evidence of a strong trophic interaction between them. This new information on theresources involved would allow an optimization of the fisheries management under an ecosystem-based criterion.