Bridging proxy reference points to sustainable yields to support data-limited fisheries

Abstract

Many of the world fisheries, especially small-scale fisheries, are in data-limited situations, for which proxy Biological Reference Points (BRPs) derived from per-recruit analyses are widely used to inform fisheries management. However, due to limited information on stock recruitment, per-recruit analyses usually assume constant recruitment and the influences of this key assumption have not been fully understood. In this study, we combined per-recruit analyses and stock-recruit relationship to build equilibrium models for eight species with different life history traits, and used the management strategy evaluation (MSE) framework to assess the uncertainty of proxy BRPs in achieving fisheries sustainability. Our results showed substantial variations in the performances of proxy BRPs on maintaining yield and biomass, and even conservative BRPs, e.g. F0.1 caused overexploitation in half of the cases (4 out of 8). The divergence of the performance between proxy BRPs and FMSY could be substantial, depending on steepness of stock-recruit relationships (correlation ranged from –0.55 to 0.9 for yield, and 0.53 to 0.96 for biomass). Accordingly, we presented an empirical approach for remediation, using correction coefficient to adjust the traditional proxy BRPs. The empirical approach showed satisfactory performances in the validation processes with an independent dataset. This paper demonstrates that proxy BRPs may introduce risks in achieving fisheries sustainability, whereas the errors can be readily adjusted with empirical estimates of steepness for most data-limited fisheries.