Abrupt declines in fish productivity often precede stock collapses in marine fisheries.

Marine life is under multiple pressures, including climate change and overfishing, which can threaten fishery sustainability especially when it results in large, abrupt, and persistent shifts in fish productivity. Reports of abrupt shifts in marine systems are not uncommon, but a global assessment of their occurrence and drivers is seriously lacking. Here, we systematically classified the temporal dynamics of fish stock productivity from agency-assessed fisheries worldwide. We detected productivity abrupt shift in more than a quarter of the 315 fish stocks analyzed. Abrupt declines were markedly overrepresented in marine regions with highest warming rates, while abrupt increases were more likely under lower fishing intensity. We also demonstrate that abrupt productivity declines preceded stock collapses by about a decade in a quarter of the stocks that shifted. Overall, our results highlight the importance of considering productivity abrupt shifts to prevent an increasing risk of fish population collapse in warming oceans.