Benthos of the Argentine-Uruguayan Common Fishing Zone

BREMEC CLAUDIA; SOUTO VALERIA; ESCOLAR MARIANA; DIEGO A. GIBERTO; LAURA SCHEJTER; ACHA EDUARDO M.; HERMES W. MIANZAN,

Aberdeen

Conferencia; 2011 World Conference on Marine Biodiversity; 2011

Benthic species composition, richness and assmeblages were studied in the Argentine-uruguayan Common Fishing Zone (AUCFZ). The objectives of this study are to give information of the benthic habitat where higher densities of pre-recruits of common hake were collected during 2009 and to comparethe distribution and abundance of benthic invertebrates with data obtained during 1993 in AUCFZ. The study area comprises soft bottoms located between 34.5ºS and 38.1ºS and between 51-206 m depth, where 48 locations distributed in 8 transects were sampled. A total of 177 benthic species were registered in the study area. A conspicuous assemblage characterized by Eunice magellanica, Sycozoa sp. and Trypalea clavaria was distributed up to nearly 80m depth (reached 135m northwards) and showed the higher abundance of pre-recruits of common hake. Deeper locations between 36ºS-38ºS were populated by the scallop Zygochlamys patagonica fishing grounds; some of the associates species showed variations in istribution and dominance when compared with data from 1993, before the scallop fishery started. We underline both the favorable habitat architecture provided by erect taxa in the settlment areas of hake pre-recruits and the non-favorable conditions in deeper bottoms at the shelf break frontal system with intensive trawling of Patagonian scallop.