The South‑east Australia Marine Ecosystem Survey (SEA‑MES) is a multi‑year research program designed to document ecosystem change in one of the world’s fastest‑warming ocean regions and to identify the drivers of those changes. Using data collected on four voyages of Australia’s premier multi‑purpose oceanographic research vessel, RV Investigator, SEA‑MES integrates climate observations, plankton sampling, habitat imaging, and extensive demersal trawl surveys to assess shifts in fish abundance, distribution, size structure, and trophic composition. Early results show declining CPUE for many species despite reduced fishing pressure, limited recovery of historically overfished stocks, and widespread changes in depth and latitudinal distributions. Comparative analyses with 1990s fishery‑independent surveys reveal altered size and length–weight relationships, and trophic relationships. These findings are providing nationally significant evidence by informing fisheries management, including AFMA climate and ecosystem assessments, threatened species evaluations, and by testing past spatial management decisions. The survey is strengthening Australia’s capacity to sustainably manage fisheries and plan for climate adaptation by providing a comprehensive baseline for understanding changes in south‑east Australia and supporting hypothesis‑driven analyses.