Updated stock assessment of Neon flying squid in the Northwest Pacific using JABBA model up to 2025

This study provides an updated stock assessment of neon flying squid in the Northwest Pacific Ocean through 2025 using JABBA (Just Another Bayesian Biomass Assessment). The assessment incorporated NPFC-compiled catch data and Chinese squid-jigging CPUE series, including nominal CPUE and standardized CPUE indices derived from generalized additive model (GAM), random forest (RF), and gradient boosting model (GBM). A total of 12 assessment scenarios were conducted, combining three stock units (winter–spring cohort, autumn cohort, and stock-wide population) with four abundance indices. The stock-wide assessment based on GAM-standardized CPUE was selected as the base-case scenario, with additional retrospective analysis and short-term projections conducted. All assessment scenarios showed satisfactory convergence and model diagnostics. The results indicated consistent declines in fishing mortality in recent years, while estimated biomass levels varied among CPUE scenarios. The autumn cohort showed relatively consistent stock status across different CPUE scenarios, whereas the winter–spring cohort and stock-wide assessments showed more conservative stock status when standardized CPUE indices were applied. Projection results suggested that lower catch levels would support stock recovery, while higher fishing pressure could increase the risk of stock depletion. These findings provide updated information on neon flying squid stock status and highlight the importance of considering multiple CPUE scenarios in future assessments under the NPFC management framework.