Spatial patterns of summer demersal fish assemblages around the Antarctic Peninsula and South Shetland Islands

During the research programme conducted on the OV Puerto Deseado in the summers of 2011 and 2013, 36 stations were sampled using a demersal net at depths between 53-590m in the Antarctic Peninsula and South Shetland Islands. Atotal 3378 fish specimens belonging to 36 species were recorded. Notothenidae was the best-represented family in species number, with Lepidonotothen nudifrons, L. larseni and Trematomus scotti being the most numerous species. Of the fish assemblages, 20% of the species were considered as dominant, 10% as common, 13% as occasional and 57% as rare. Six groups (and two sub-groups) were obtained by the ordination diagram based on geographical location: group 1 = Gerlache Strait, group 2 = Deception Islands, group 3 = Biscoe Island, group 4 = between Elephant and King George islands, group 5 = northern Antarctic Peninsula, and group 6 = South Shetland Islands, with sub-groups 6a shallower South Shetland Islands and 6b deeper South Shetland Islands. Sampling depth and water temperature significantly explained the spatial pattern. A latitudinal pattern of decreasing abundance from north-east to south-west was found in L. larseni and the opposite in T. scotti. The predictability of fish composition in the assemblages' areas could be a useful tool for ecosystem-based management.