Evaluating harvest control rules under recruitment regime shifts: Evidence from static and dynamic reference biomass in the anchovy fishery of the southern Humboldt ecosystem

Resumen: Biomass at Maximum Sustainable Yield (B_MSY) is traditionally used both to assess fishery status and to establish catch limits through a harvest control rule (HCR). These B_MSY may be fixed or dynamic depending on data availability and management objectives. Although B_MSY is often treated as a fixed reference, recruitment variability and regime shifts may require a dynamic biomass reference, with important implications for management and the sustainability of short-lived species such as small pelagic fish. This research investigates recruitment variability in the anchovy fishery of the southern Humboldt ecosystem and the adaptability of fisheries management to such variability. We evaluated the performance of the population status indicator (B/B_MSY) through HCR and different operating models representing recruitment scenarios. Our results show that the performance of the HCRs varies depending on the B_MSY criterion applied, and that the effectiveness of the stock status metric is influenced by both the HCR and the productivity scenario. Static reference points, when combined with ramp-type HCRs, resulted in higher biomass and lower overexploitation risk under high uncertainty, whereas dynamic reference points enhanced adaptability to persistent productivity shifts when paired with precautionary rules that buffered variability. Practical implication. No single optimal strategy exists; fisheries management should adopt an integrated, adaptive approach that considers combinations among reference points, HCRs and stock dynamics, considering periodic Management Strategy Evaluation (MSE) with precautionary measures to ensure sustainability under variable productivity.