Evidence is mounting for long-term effects of climate change on marine fish assemblages. Until now, much of this work has been conducted over short or intermittent time periods, or small geographical areas. I will present the emerging results of a macrospatial study of the entire UK marine fish assemblage measured annually for the last 30-years by commercially-independent trawls. There is clear support for the previously reported North Sea shift in community assemblage in the late-80s to early-90s, but also evidence of community change in NW Scotland, the Channel, and the Celtic and Irish Seas. Using newly developed analytical approaches we have explored these patterns at a fine spatio-temporal resolution, and examined relationships between measured community change and key environmental drivers. Through a series of hypothesis-driven investigations of these patterns, we have explored the species-level responses with respect to temperature and depth preferences, and life-history characteristics of each species. We hope to use these findings to draw out fundamental properties of ecosystem function, community response, and life-history vulnerability, and by extrapolating current trends we aim to produce ‘best guess’ predictions for the future of marine fish assemblages and fisheries.