Analysis of catch data from a deepwater trawl survey conducted at South Georgia and Shag Rocks in 2003 indicate that depth and region have a marked influence over demersal fish community structure at South Georgia and Shag Rocks. Three distinct, depth stratified fish assemblages were observed. The demersal fish assemblage found on the shelf to depths of around 400m is dominated by notothenids and is comprised largely of species endemic to the Southern Ocean and Scotia Sea. At increasing depths (400-600m) diversity increases with the presence of many benthopelagic species including Stomiiformes, Aulopiformes and Zoarcids. At the greatest depths sampled the demersal fish community is dominated by gadiform fishes including members of the Macrouridae and Moridae many of which are not endemic to the Southern Ocean. Clear regional differences in the shelf community are apparent with differences observed in community structure between South Georgia and Shag Rocks to depths of around 400m. The biogeographic patterns observed in demersal fishes show similar trends to those seen in a range of other taxa such as crustaceans.
Mr Doug Cooper (CCAMLR Secretariat)