We investigated the biomass, carbon demand, and secondary production of under-ice fauna (here metazoans >300 μm) at eight stations in the Arctic Ocean, north of Svalbard. Sampling was conducted during spring in 2015 with the Surface and Under Ice Trawl (SUIT). The biomass (µgCm-²) for under-ice fauna taxa was calculated by multiplying abundances (ind. m-²) of each taxon obtained from Ehrlich et al. (2020) by the carbon content per individual of this taxon. The mass-specific ingestion rate of each taxon was multiplied by the total biomass of that taxon at every station to determine the carbon demand per day (µgC/m²/day). The secondary production of under-ice fauna was calculated by using a P/B ratio from Forest et al. (2014) for large Arctic mesozooplankton species.