Deep-sea near-bottom swarms of pelagic amphipods<i>Themisto:</i>observations from submersibles

Abstract

AbstractSwarms of Themisto abyssorum and one of Themisto libellula (Hyperiidea, Hyperiidae) were observed during four dives of Mir deep-sea manned submersibles in the Norwegian and Greenland Seas at depths of about 1000 m. Concentrations of the amphipods in the most dense swarm were as high as high as 25–38 individuals per cubic meter in the layer 100–5 m above the bottom. However, such swarming does not seem to be obligatory for Themisto. The animals picked up (food?) particles directly from the seabed.Keywords: Themistonear-bottom swarmssubmersibles