This dataset comprises conventional stomachs contents data for the biomass-dominant species of mesopelagic fish, particularly myctophid fish (Family Myctophidae) in the Scotia Sea. The data were collected by depth-discrete RMT25 net trawls deployed between 0-1000 m between the Antarctic Polar Front and the South Orkney Islands. Samples were collected repeatedly at nominal sampling stations during austral autumn 2004, spring 2006, summer 2008 and autumn 2009 for analyses examining the trophodynamics of Southern Ocean mesopelagic fish and their role in the food web. The data are the quantitative measures of diet composition (prey abundance, frequency and mass) observed from microscope analyses of individual fish stomachs per species.

Mesopelagic fish were sampled in the Scotia Sea using a 25 m2 opening and closing rectangular midwater trawl during five research cruises on RRS John Biscoe and RRS James Clark Ross. Nets sampled discrete layers, from the surface to 1000 m during austral spring, summer and autumn. The data include 17726 individual fish records from 66 taxa, the most abundant of which were myctophids of the genera Electrona, Gymnoscopelus, Krefftichthys and Protomyctophum and bathylagids (Bathylagus sp.). Length (standard length, total length or pre-anal fin length) was measured for the majority of specimens (16837), with sex and weight data also collected for many. The work was conducted as part of the BAS Ecosystems Programmes funded by the UK Natural Environment Research Council.

This dataset contains occurrence records for ten Southern Ocean myctophid fish species that have been downloaded and cleaned from the online biodiversity repository GBIF. As well as providing GBIF documented metadata for each occurrence record, this dataset provides environmental conditions - specifically bathymetry, temperature, salinity, dissolved oxygen and net primary productivity - for each record. Both sea-surface and depth-specific values for the temperature, salinity and oxygen variables are given in separate data files. A third data file of corresponding background points and their associated environmental conditions is also provided. Together these data were used as input files for the MaxEnt ecological niche models within the peer reviewed article: Freer JJ, Tarling GA, Collins MA, Partridge JC, Genner MJ (2020) Estimating circumpolar distributions of lanternfish using 2D and 3D ecological niche models, Marine Ecology Progress Series.