the association of antarctic krill euphausia superba with the under-ice habitat协会的南极磷虾euphausia superba冰层中的栖息地.pdf

The Association of Antarctic Krill Euphausia superba with the Under-Ice Habitat 1,4 ¤ 1 2 3 4 Hauke Flores * , Jan Andries van Franeker , Volker Siegel , Matilda Haraldsson , Volker Strass , 1 4 5 Erik Hubert Meesters , Ulrich Bathmann , Willem Jan Wolff ¨ 1 Institute for Marine Resources and Ecosystem Studies (IMARES), Texel, The Netherlands, 2 Johann Heinrich von Thunen Institute for Sea Fisheries, Hamburg, Germany, ¨ 3 Department of Marine Ecology, University of Gothenburg, Fiskebackskil, Sweden, 4 Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, Germany, 5 Center for Ecological and Evolutionary Studies, University of Groningen, Haren, The Netherlands Abstract The association of Antarctic krill Euphausia superba with the under-ice habitat was investigated in the Lazarev Sea (Southern Ocean) during austral summer, autumn and winter. Data were obtained using novel Surface and Under Ice Trawls (SUIT), which sampled the 0–2 m surface layer both under sea ice and in open water. Average surface layer densities ranged between 0.8 individuals m22 in summer and autumn, and 2.7 individuals m22 in winter. In summer, under-ice densities of Antarctic krill were significantly higher than in open waters. In autumn, the opposite pattern was observed. Under winter sea ice, densities were often low, but repeatedly far exceeded summer and autumn maxima. Statistical models showed that during summer high densities of Anta