The commercial harvest of the range-extending Longspined Sea Urchin (Centrostephanus rodgersii) in Tasmania has been rapidly accelerated by catch subsidies initiated by the Abalone industry. Extensive overgrazing of kelp by urchins represents the largest and most immediate threat to the $AUD81 million abalone industry and reef ecosystems more broadly. Subsidy payments provided the urchin industry with some financial reassurance to overcome barriers associated with infrastructure, processing knowledge and market development. After a decade of urchin industry fluctuations pre-subsidy, harvests of urchins quickly rose to 500 t pa after its inception, resulting in extensive kelp protection and localised kelp restoration in areas of intense urchin fishing. The early action to prevent extensive urchin overgrazing along the 250 km Tasmanian east coast has been both effective and affordable, as prevention of hyper-stable extensive barren grounds being substantially lower in effort and cost than rehabilitation. Spatially variable subsidies have seen urchin control effort redistributed to regions of high importance, with additional actions (‘take-all’ harvests and culling) also reducing abundances on high value reefs. Here we document that with cooperative support and prioritisation by governments, industry, and researchers, harvest can be an affordable and effective management strategy for urchin management over large scales.