Methodology:

The data were collected during expeditions JR179 in 2008 and JR17003a in 2018.

The EBS holds an epi-and a suprabenthic netsampler (Brenke, 2005). Each of these nets has an opening of 100x33 cm and net mesh size of 500 µm. The cod ends are equipped with net-buckets containing 300 µm mesh windows. On deployment 1.5 times cable length to water depth were laid out and then EBS was trawled for 10 minutes on the seabed at a 1 knot for deployments in 500 m to 1500 m. Once on the deck, the content of the samplers was immediately fixed in 96% undenaturated and pre-cooled (at -20°C) ethanol. Samples were stored in a -20°C freezer for at least 48 h to reduce degradation of DNA for subsequent genetic studies. During this time, samples were gently rolled every three to six hours. Ethanol was changed once for all sub-fractions.

The haul distances were calculated based on equation (4) in Brenke (2005). For comparison between stations abundance data were standardised to 1000 m2 trawled area.

In the laboratory, samples were initially sorted under a stereomicroscope to class level and, whenever possible, classified to morphospecies level. Juvenile specimens were assigned to family or genus level. Live specimen numbers were counted for abundance data based on undamaged individuals and heads while tails (without head) were not taken into account.

Data collection:

British Antarctic Survey Epi-benthic Sledge was built based on the EBS design by Brenke (2005), further details can be found at http://vocab.nerc.ac.uk/collection/L22/current/NETT0182/.

Data quality:

Standard protocols for EBS deployment were followed. Data entry of EBS deployment data was linked to vessel's USBL system.