Environmental variability plays a key role in shaping the productivity of many fisheries, and understanding how species respond to such variation is essential for their sustainable management. This is especially true for species inhabiting dynamic freshwater, estuarine or near-shore habitats, where inter-annual variation in rainfall can drive profound fluctuations in stock size and population demographics. However, identifying suitable approaches to integrate environmental variability into management frameworks poses a notorious challenge – a challenge which is compounded in the absence of reliable biomass estimates. In northern Australia, the Barramundi fishery is a notable exemplar of an environmentally-driven fishery, with recruitment and catchability strongly and positively correlated with wet season rainfall. Here, I will describe a relatively simple, novel approach devised to identify periods in time and space where environmental conditions restrict or enhance the stock biomass available to the Northern Territory commercial barramundi fishery, enabling harvest rules to be strengthened or relaxed accordingly. Our method combines Year Class Strength ~ rainfall relationships, age and growth data, and gear selectivity information to develop fishery performance indicators within the harvest strategy.