The Biological Investigations of Marine Antarctic Systems and Stocks (BIOMASS) Data Set has been created as part of the BIOMASS Programme directed towards deeper understanding of the ecology of the Southern Ocean, with emphasis on krill (Euphausia superba). Data were collected during 34 cruises through a collaboration by 12 countries during three field experiments. These were: the First International BIOMASS Experiment (FIBEX) from November 1980 to April 1981, the Second International BIOMASS Experiment (SIBEX), Part 1 from October 1983 to May 1984 and Part 2 from November 1984 to April 1985. Data were collected on krill distribution from acoustic surveys and krill population structure from net-hauls. Supporting data from ichthyoplankton net-hauls, oceanographic stations (temperature, salinity, nutrients and chlorophyll-a) and observations of sea-birds at sea were also collected. The BIOMASS Data Set is composed of 43 data files, extracted from the BIOMASS Oracle relational database created by the BIOMASS Data Centre that collated and standardised the data. The validation and correction of the data were carried out during data analysis workshops by the BIOMASS Programme scientists who collected the data. The majority of the BIOMASS data have been utilized during BIOMASS workshops. However, some have not been used and must be regarded as unvalidated. The documentation accompanying the BIOMASS data set lists the known problems and validation status of the data. Funding: The BIOMASS Data Set has been generated by the BIOMASS Data Centre funded by the British Antarctic Survey. Main sponsors of the BIOMASS Programme were the Scientific Committee on Antarctic Research (SCAR) and the Scientific Committee on Oceanic Research (SCOR) in collaboration with the International Association for Biological Oceanography and the Advisory Committee on Marine Resources Research of the Food and Agriculture Organization of the UN.

DNA sequencing data from octopus samples collected in the Southern Ocean. A small tissue sample was taken from the mantle of each octopus and placed immediately in 70 - 80 % ethanol for preservation, in preparation for DNA extraction.

Biological tissue samples from octopus species collected from the Southern Ocean, James Clark Ross cruise no. JR147/145. A large collection of tissue samples from deep sea and Antarctic target groups had already been collected in previous cruises. The specific objective of this cruise was to target three species of octopus, Pareledone charcoti (peak abundance 100m depth), Pareledone turqueti (peak abundance 100-200m) and Adelieledone polymorpha (peak abundance 250-350m), for the micro-evolution (i.e. population genetics) component of the project. Most of the octopuses were captured with an otter trawl, due to its relatively large sampling area and the fact that it can be trawled quickly (4 knots) which prevents octopuses from swimming out of it.