Forecasts of an El Niño in 2023/24 raised concern amongst Australian marine stakeholders regarding the potential impacts on marine industries and systems. National level seafood-focused climate briefings were requested by the fisheries sector for the first time, driven by various state and regional level meetings and information requests. To respond to stakeholder needs, five virtual national marine climate briefings were undertaken through the 2023/24 summer, underpinned by new sub-seasonal to seasonal marine heatwave forecast capabilities. These briefings were developed in collaboration with multiple science organisations and were targeted to industry and management authorities across the Australian seafood sector. Targeted information products, additional regional and sector-specific briefings, and state response plans were developed as a result. Collectively, these briefings were a catalyst for positive and rapid action in policy, management, industry, and research arenas. This experience showed that the combination of seasonal forecasting capability, inter-agency co-ordination, strong stakeholder engagement and effective science communication, plays a critical role in improving the understanding, planning and responses to extreme events.