Population status of mackerel (Scomber japonicus), anchovy (Engraulis mordax), and Pacific anchoveta (Cetengraulis mysticetus) in the Gulf of California, México

In this study, the CMSY++ framework was applied with a Bayesian Schaefer model (BSM) to assess the status and management implications of Pacific mackerel, northern anchovy, and Pacific anchoveta in the Gulf of California. The results indicate that despite declines in biomass, all three stocks are currently estimated to be exploited at levels consistent with sustainability targets, with fishing mortality (F) below F at the maximum sustainable yield (F MSY ) and population biomass (B) above B at the maximum sustainable yield (B MSY ). However, because the relative abundance of northern anchovy and Pacific anchoveta is informed by commercial catch per effort unit (CPUE), recent stock status estimates for these two species should be interpreted with caution due to potential changes in catchability and targeting behaviour over time, whereas inferences for Pacific mackerel are supported by a fishery-independent abundance index. Retrospective and sensitivity analyses revealed that the biomass-based indicators were generally robust, whereas the fishing mortality estimates were more sensitive to end-of-year data, particularly for northern anchovy. These findings support the implementation of a precautionary harvest control rule based on annual biomass estimates to sustain small pelagic fisheries under data-limited conditions. We propose a maximum exploitation threshold of 0.8*F MSY , which should be reduced when the stock size reaches 0.5*B MSY and further to zero at 0.25*B MSY for mackerel and Pacific anchoveta and 0.20*B MSY for northern anchovy.