<p>Across its broad Australian range, the teleost fish species Snapper (<i>Chrysophrys auratus</i>) has historically been a significant fishery resource. Through the 2000s, it became a national management issue due to declines in catches and stock statuses in several State jurisdictions. From 2011/12, the downturn was strongest in South Australia. Although management changes were implemented, extensive fishery closures had to be implemented in 2019. This paper considered the nature of the declines. The historic development of Snapper fishing was described to provide context for the scale of catches throughout the 2000s. Catches between 2000 and 2012 were likely the highest ever, before the ensuing significant decline. For the south-eastern region of Australia, the life history, demographic processes that drive population dynamics, and stock structure were determined. Each of three stocks is a metapopulation based around a primary nursery area in a natal region that receives the highest recruitment, although with high inter-annual variability. Adjacent regions located up to hundreds of km away are replenished through density-dependent, age-related migration. For the two stocks closed to fishing in 2019, record catches reflected the build-up in biomass from several strong year classes. However, for both, the numerous years of high catches overlapped with extended periods of poor recruitment, having a synergistic effect on biomass. Yet, the extent of declines was not obvious because of conflicting trends in performance indicators, and lack of real-time data on recruitment. Since the fishery closures, a significant science program has been initiated to inform re-opening the fisheries, to improve monitoring, stock assessments and fishery management in the future.</p>