Fisheries Phase Diagram for Status Declaration of Stocks With Fluctuating Population Dynamics

Fish stocks are in a continuum between smooth and fluctuating population dynamics. The Kobe plot is a graphical standard widely used for status declaration with respect to MSY‐based biological reference points (BRP). However, these BRP are inadequate for stocks with fluctuating dynamics. Their use leads to abrupt shifts from sustainable to overfished‐overfishing even when abundance is long‐term non‐declining. A more general phase diagram, built with BRP from the mean latent productivity (), leads to sustainable status in four stocks of small pelagic fish and octopus that have fluctuating yet non‐declining abundance. Conversely, the Kobe plot portraits them abruptly switching between sustainable and overfished‐overfishing status. In a fifth stock with smooth dynamics, and diagrams produce the same status. Complementing previous recommendations to set harvest rates of stocks with fluctuating dynamics at the , we recommend that status declaration of these stocks be made with MLP‐based BRP in phase diagrams.