This study was undertaken by the South Australia Research and Development Institute (SARDI) in collaboration with PIRSA Fisheries and Aquaculture, BDO EconSearch, the Marine Fishers Association (MFA), Fishwell Consulting and University of Canberra. This project guided the reform of South Australia’s commercial Marine Scalefish Fishery (MSF) by providing scientific advice and analyses to underpin its implementation. The MSF is a multi-sector, multi-gear and multi-species fishery, making any management reform a complex and difficult process. Both the sustainability of key stocks and commercial fishery’s economic performance have been deteriorating over a 20-year period; significantly influenced by fishery overcapitalisation. Simply put, there were too many fishers and not enough fish to support a vibrant and sustainable commercial fishery. This was addressed through the three ‘pillars’ of the reform: regionalisation, unitisation and rationalisation. These pillars were reflected in the reform with: 1) the creation of four new zones of management; 2) implementation of individual transferable quotas (ITQs) for appropriate ‘Tier 1’ stocks; and 3) rationalisation of the commercial MSF fleet by removing one third of licences through a voluntary licence surrender program (VLSP). These pillars were supported by research on the biological, economic and social carrying capacity of the fishery. The reform was implemented on 1 July 2021 resulting in a fishery that has regional management with appropriate output controls and a reduced fleet size.