Toward sustainable use of dolphinfish (Coryphaena hippurus) in the Northwest Pacific: A framework for stock assessment and management strategy evaluation

Abstract

This study presents an integrated framework that combines age-structured stock assessment with management strategy evaluation (MSE) to support the sustainable management of dolphinfish (Coryphaena hippurus) in the Northwest Pacific Ocean. Using fishery-dependent data from Taiwan, including catch, standardised CPUE, and length composition, the assessment indicated that the stock is currently above SSBMSY and that fishing mortality remains below FMSY. To evaluate candidate management procedures (MPs) for setting future total allowable catches (TACs) under several uncertainties, a simulation-based MSE was implemented using a precautionary operating model with multiple stochastic replicates. Four different harvest control rules (HCRs) as main components of MPs were tested to assess trade-offs between biological safety and catch performance. Among these, a precautionary HCR demonstrated strong performance across conservation indicators, providing a practical example of how the framework can inform precautionary decision-making. Despite regional data constraints, the study demonstrates how MSE can be applied under data-limited conditions to evaluate strategies transparently and systematically. The modular design allows for future integration of environmental drivers, socio-economic considerations, and broader regional data inputs, offering a foundation for science-based, cooperative management of transboundary pelagic species in the region.