Abstract
With novel ocean conditions rapidly appearing as the result of climate change, basing decisions about fisheries and other ocean activities on historical conditions is no longer tenable. There is instead a widespread need for shifting ecological baselines to more effectively guide decisions into the future. What has not been as widely recognised is that the relevant timescales differ substantially across ocean‐related decisions, from lead times of hours to decades depending on the decision being made, and that this range necessitates a matching range of ecological forecast products across similar timescales. At the moment, a predictability gap exists at intermediate timescales, from multi‐annual to multi‐decadal forecasts. Because most fisheries and many other ocean activities rely on biological conditions like fish abundance or distribution, the ecological inertia of organismal growth, generational turnover, movement, and food web dynamics can help push ecological forecasts further across this gap. To realise this potential for more effective and usable ecological forecasts, coordinated research and implementation at the intersection of biology, climate science, social science, and decision‐making is needed. These efforts will be critical for forecasting shifting ecosystem baselines and sustaining fisheries, ocean ecosystems, and the ocean economy in the coming decades of rapid change.