Biomass (mg dry mass m-3) of zooplankton taxa was calculated from samples of Polarstern cruise PS78 (ARK-XXVI/1) on a transect across Fram Strait. Individual dry mass was calculated converting wet mass (biovolume) to dry mass for Arctic mesozooplankton taxa. The conversion factors for specific taxa are listed in Cornils et al. 2022 (Table 3). Samples were taken with the Multinet midi (Hydrobios, Kiel), which is equipped with five nets (mesh size: 150 µm). Samples were analysed via image-based ZooScan analyses. The classified images are available at the web application EcoTaxa: https://ecotaxa.obs-vlfr.fr/prj/2771