An international study has led to the creation of the world’s first global database of jellyfish records to map jellyfish populations in the oceans. The debate regarding future trends, and subsequent ecological, biogeochemical and societal impacts, of jellyfish and jellyfish blooms in a changing ocean is hampered by a lack of information about jellyfish biomass and distribution from which to compare. To address this knowledge gap, scientists used the Jellyfish Database Initiative, or JeDI, to map jellyfish biomass in the upper 200m of the world’s oceans and explore the underlying environmental causes driving the observed patterns of distribution....