The profound environmental shifts in the Arctic region lead to far-reaching alterations of the composition and structure of marine populations and communities and cause pronounced quantitative and qualitative changes in ecosystem functioning. The expected decline of the sea-ice is hypothesized to weaken pelagic-benthic coupling, result in a shift from benthic-dominated to zooplankton-dominated energy flow pathways. Such release of energy in the pelagic zone is assumed to be followed by fish communities. Thus, it was hypothesized that the fish stock will likely increase in the ice-free areas. However, carnivorous "jellies" (gelatinous zooplankton) can radically affect such scenarios and outcompete fish communities. Gelatinous zooplankton is well known for its transformative effect on the structure of food webs and its role in the disastrous fish collapses worldwide. Despite their potential impact on the Arctic food webs, their ecological roles have been poorly studied and oversimplified. For this purpose, data on jellyfish species distributions for the entire Arctic Ocean and adjacent seas will be collected based on existing scientific literature and public databases. In addition, a network of various scientific experts/collaborators will be established in order to compile state-of-the-art dataset for the Arctic region. Based on this collection of historical data as well as the data of jelly species derived from newly obtained optical and/or acoustic datasets (incl. data from recent international campaigns), advanced spatial statistical techniques such as Species and Community Distribution Models (SDMs and CDMs) will be applied in order to understand current patterns of species distributions and their realized niche. The modelling effort will also incorporate data on fish species into CDMs in order to determine the potential interaction between fish and jellies. Moreover, the implemented models coupled with climate change scenarios will allow us to forecast potential changes in ecosystems, predict future range-expansions and identify climate change winners and losers among the jelly species (and major fish stocks). The output of the species- /community-based models could be considered as a powerful model-based mapping tool for informing ongoing and planned spatial conservation management in the Arctic region. Moreover, application of the community-based models on a long-term basis would offer an opportunity to identify ‘hotspot’ regions of ‘jellification’ (i.e. the increase of jelly biomass), which are characterized by particularly pronounced biodiversity changes, and thus guide future field activities in the Arctic region.