Large fisheries declines linked to compound and extreme climate events.

Climate extremes are increasingly disrupting marine ecosystems and fisheries. However, evidence on extreme ocean temperature effects on fish stocks and fisheries is mixed, and the combined impacts of heat and productivity extremes remain unclear. Using three decades of global data encompassing 6659 time-series for 1246 species across 254 regions, we conduct a risk-based analysis to quantify how local extreme high temperatures and low ocean productivity that these species are exposed to, alone and together, affect local fisheries catches. These events, particularly when compounded, sharply increase the likelihood of local extreme low catch events, especially in tropical and subtropical regions. Species critical to food security and conservation are disproportionately affected, with widespread risks in socio-economically vulnerable countries. Without adaptation, extreme events' risks are projected to strongly intensify by the mid-21st century. Strengthening monitoring and climate-responsive fisheries management is urgently needed to build resilience.