Seamounts, deep-sea corals and fisheries - an ubiquitous ocean floor feature, a key marine ecosystem, and an important human activity: together they have created one of the most critical ocean issues. The report reveals the global scale of the vulnerability of habitat-forming stony corals on seamounts, and that of associated marine biodiversity and assemblages, to the impacts of trawling, especially in areas beyond national jurisdiction. It provides some of the best scientific evidence to date to support the call for concerted and urgent action on the high seas to protect seamount communities and their associated resources from the adverse effects of deep-water fishing. The report describes the results of data analyses that were used to understand the global distribution of deep-sea corals on seamounts, to model the distribution of suitable habitat for stony corals, and to appreciate the extent of the trawl fisheries on seamounts in areas beyond national jurisdiction. These results were combined, along with knowledge of the effects of trawling on corals and other seamount species, to identify the main areas at risk from the impact of current and future trawling on the high seas. In particular, seamount ecosystems in the Indian, North and South Atlantic, and the South Pacific Oceans, are threatened by the expansion of alfonsino (250-750 metres) and orange roughy (750-1200 metres) fisheries.