Benthic invertebrates by-cacht of demersal fisheries: a comparison between Subantartic and Antartic shelf waters (45S-57S)

ROUX, A.; BREMEC, C.S.; SCHEJTER, L.; GIBERTO, D.A.

Ushuaia

Congreso; IBMANT/ANDEEP International Symposium & Workshop; 2003

Subantarctic and Antarctic demersal fish stocks have been intensively exploited during the last twenty five years. Target species in the argentinian continental shelf are mainly Macruronus magellanicus, Merluccius australis, Micromesistius australis, Genypterus blacodes and Salilota australis, while in Shag Rocks and South Georgia shelves are Notothenia rossii, Champsocephalus gunnari and Dissostichus eleginoides, among others. It is well documented that trawling activities can affect benthic communities by removing or injuring living organisms, in the path of the gear or by digging into the sediment, affecting both the epifauna and the infauna. In a fisheries context, the objective of the benthic by-catch sampling is to characterize different fishing grounds and to recognize possible effects of trawling on them. The information obtained on invertebrates by-catch, during 4 cruises carried out by INIDEP and 1 INIDEP-IAA joint cruise aimed at the assessment of fish stocks, is herein used to identify possible relations between the argentinian continental shelf -Subantarctic Region- and the north-east area of the Scotia Arc -Antarctic Region- and to determine if transitional zones – gradual or abrupt - are present, through the analysis of community structure (distribution, composition, feeding guilds). This is the first analysis of a benthos database that totalizes more than 300 stations distributed between 45°S and 57°S, sampled between 1992 and 1994 (ver Pdf adjunto)