Evaluating performance of data-limited management procedures in an ecosystem perspective: A case study for Larimichthys crocea (Sciaenidae) in the Min River Estuary, China

Abstract

Management Strategy Evaluation (MSE) evaluates the performance of alternative management strategies. However, the potential ecosystem effects of the management procedures (MPs) are less evaluated. As one of the four top commercial marine fisheries of China, the fishery of the large yellow croaker Larimichthys crocea (LYC) collapsed in the late 1980s due to the exceeded fishing pressure on spawning and over-wintering aggregations. Long-term and large scale restocking programs for the recovery of LYC fishery have been conducted widely along the eastern coast of China, but its ecosystem impacts and ecological carrying capacity (ECC) were not well understood and assessed. The species-specific assessment and management for LYC fishery were lack due to limited data availability. In this study, an Ecopath model was built as the operating model in MSE to evaluate the effects of MPs for the LYC fishery and estimate the LYC ECC in the Min River Estuary to explore the optimal management measure. A total of 12 candidate MPs were identified and tested, including 5 input controls (2 fishing-effort-based and 3 length-based) and 7 catch-based output controls. A 20-year simulation showed that only 4 MPs fully achieved the performance criteria in maintaining biomass and avoiding further overfishing, including curE75 (75 % of current fishing effort levels), minlenLopt1 (the minimum length of retention for maximizing biomass), matlenLim (fishing retention-at-length related to the maturity curve: 100 %) and matlenLim2 (fishing retention-at-length related to the maturity curve: 110 %). The Min River Estuary ecosystem could support up to 17 kg/km2 of LYC. The Ecosim model projects that the LYC biomass increased over 20 % after the application of curE75, and over 37 % with the combination of curE75 and national fishing moratorium policy after the 20-year simulation. The combination of releasing, fishing effort reduction and fishing moratorium is the optimal measure within current management systems for the recovery of LYC fishery in the Min River Estuary. This study provides an ecosystem-based fishery management approach to plan and evaluate restocking programs using data-limited methods and MSE for the LYC and other fisheries.