This database provides the most comprehensive systematic list of mega-epibenthic assemblages in the Australian Economic Exclusive Zone (AEEZ) of Heard Island and McDonalds Islands (HIMI) at water depths between 168 and 970 m. Data were collected to better understand the types and distribution of benthic invertebrates, their vulnerability to bottom fishing, and the effectiveness of the HIMI Marine Protected Area (MPA) for representing and protecting the regions benthic biodiversity. A total 504 taxa from 14 phyla were collected from 129 stations throughout HIMI. Two methods, beam trawl (for non-complex flat terrains) and epibenthic sled (for more complex, rough terrains), were used to sample the megabenthos. Both the trawl and sled were fitted with a 1 cm-2 mesh cod-end with a net opening (height x width) of 2.7 x 1.2 m for the beam trawl and 1.2 x 0.6 m for the epibenthic sled. Samples were sorted into broad taxonomic groups onboard the sampling vessel then frozen for later analysis. In the laboratory, samples were sieved over a 1 cm mesh and all dead material removed. Megabenthos were identified to the lowest possible taxonomic level by using the available literature and assistance of taxonomic specialists. All non-colonial taxa were counted and then weighed. Colonial taxa that could not be counted as individuals, e.g. demosponges and bryozoans, were separated to the lowest taxonomic level and a whole weight recorded per sample. Taxonomic expertise was provided by Dick Williams (Osteichthyes and Chondrichthyes) of the Australian Antarctic Division; Daphne Fautin and Andrea Crowther (Actinaria) of the University of Kansas; Cardin Wallace (Actinaria) from Queensland Museum; Elizabeth Turner (Bivalvia and Gastropoda) and Genefor Walker-Smith (Invertebrates) from the Tasmanian Museum and Art Gallery; Phillip Bock (Bryozoa), Mark Norman (Cephalopoda), Gary Poore (Crustacea), Joanne Taylor (Decapoda), Mark O'Loughlin (Holothuriodea), Jan Watson (Hydrozoa), Tim O'Hara (Ophiuroidea and Asteroidae), Robin Wilson (Polychaeta) and David Staples (Pycnogonida) of Museum Victoria; Igor Smirnov (Ophuroidea) of the University of Russia; and Andrew Hosie (Cirripedia) of the Western Australian Museum. A reference collection of the taxa is lodged at the Tasmanian Museum and Art Gallery, Hobart, Tasmania. On 2022-11-02 a minor data update was made to add scanned copies of old worksheets.

Two components. The first component is an even log for all station and instrument deployements. The second component is a log where start and end bottom times need to be recorded for instruments for example the benthic trawl. There is one file for each of the logs. Both logs need to be ideally merged into one to have one data source of event information. The start and end bottom times need to ideally go into the event logging system on the ship. 1) Event log for stations and all instrument deployments Stations and instrument deployments were recorded (including failures) over the progress of the voyage to provide a summary of all work carried out over voyage and and assigned an Event ID number for referencing data associated with these events. Data_Format Data was initially recorded in the ship board PostgreSQL database. Data was exported as a comma delimited file 'events.csv' at the end of the voyage. Column 1 - Setcode (voyage identifier of the form 200708030 meaning year 2007-08, voyage 3) Column 2 - Voyage Code (text voyage identifier) Column 3 - Transect ID (transect identifier, no transects were identified this voyage) Column 4 - Station ID (Station identifier, blank for events not associated with a station, CEAMARC project stations are pre-pended with 'CEAMARC', CASo stations are pre-pended with 'CASO', sampling near icebergs for trace metals pre-pended with 'ICEBERG', woCE SR3 transect sampling pre-pended with 'SR3'). Column 5 - Event ID (unique ID across voyage for individual events) Column 6 - Event Type (usually the instrument deployed, self explanatory. One event type 'Plankton Water Sample' refers to mass water sampling undertaken for genomics work). Column 7 - User Reference (id used by individual scientists to reference their data for this event. If left blank they are using the auto assigned event id from this table). Column 8 - Start Timestamp (start timestamp of the event in UTC). Column 9 - Start Latitude (start latitude of the event from the ship gps) Column 10 - Start Longitude (start longitude of the event from the ship gps) Column 11 - Start Bottom Depth (bottom depth at the start time of the event in metres from EK60 sounder bathymetry export) Column 12 - End Timestamp (end timestamp of the event in UTC) Column 13 - End Latitude (end latitude of the event from the ship gps) Column 14 - End Longitude (end longitude of the event from the ship gps) Column 15 - Duration (duration of the event in hours) Column 16 - End Bottom Depth (bottom depth at the end time of the event in metres from EK60 sounder bathymetry export) Column 17 - Min bottom Depth (minimum bottom depth encountered over event period from EK60 sounder bathymetry export) Column 17 - Avg Bottom Depth (average bottom depth encountered over event period from EK60 sounder bathymetry export) Column 18 - Max Bottom Depth (maximum bottom depth encountered over event period from EK60 sounder bathymetry export) Column 19 - Author (person who entered event details into logging system) Column 20 - Notes (notes peculiar to the event, may be blank) 2) Log of instrument bottom times. Excel spreadsheet 'Trawl_log_18_Jan_08_final.xls' Column A - Station number, these are all CEAMARC station numbers, matching stations in the event log pre-pended by 'CEAMARC'. Column B - Event ID (matching event log, sometimes blank as this log an contain entries on intended events that did not get carried out for some reason or another) Column C - Trawl Name (labelled trawl name, actually event type as the log started off with just trawl start/end bottom times, but was expanded to encompass other event types like grabs etc.) Column D - Date of the event. Column E - Ship Speed (in knots from displays of gps speed). Column F - Time instrument hit the water in utc Column G - Time instrument reached the bottom in utc. Column H - Time instrument left the bottom (i.e. hauling started) in utc. Column I - Time instrument on the deck (ie out of the water) Column J - Depth in meters read of EK60 sounder display (could be any time during event). Column K - Comments pertaining to the event.