Diversity of benthic communities in the recruitment areas of common hake Merluccius hubbsi Marini, 1933

The environmental and biological traits of fishes recruitment and nursery areas play a key role in their survival. In that context, the aim of this work was to characterize the diversity of macrobenthic communities linked to young-of-the-year common hake in the San Jorge Gulf region (Patagonian Shelf, PS) and the Argentine-Uruguayan Common Fishing Zone (AUCFZ). Bycatch data gathered in research cruises performed by the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP) (2005-2011) were used. 147 taxa in the PS and 165 in the AUCFZ were found, with predominance of crustaceans, mollusks and echinoderms. The total asymptotic richness estimates varied between 154-184 (PS) and 182-214 (AUCFZ). The PS displayed a lower species density than the AUCFZ and lesser richness of all values in the individuals considered. However, several of its benthic assemblages showed a larger presence of species, which results in an increase of the bottom complexity and the strengthening of shelter conditions for young-of-the-year specimens to face predation and, thus, in a higher survival level. Said hypothesis should be evaluated in the long term with studies aimed, specifically, at the benthic communities using the baseline generated by bycatch samplings.