Standardized CPUE of Japanese commercial dip-net fishery targeting spawners of chub mackerel in the Northwest Pacific up to 2026

We updated CPUE standardization of the Japanese commercial dip-net fishery for Pacific chub mackerel using a generalized linear mixed-effects model. Dip-net fishery CPUE was affected by month, area, sea surface temperature, fishing vessel, and year. The abundance index standardized for variables other than year declined markedly after remaining high from 2011 to 2021. In 2026, the standardized index fell substantially below both the previous year’s value and the previous minimum observed in 2005. However, the 2026 estimate had substantially greater uncertainty because of its much more limited temporal and spatial coverage than in previous years. Considering these limitations, we propose using the standardized index through 2025 as the base-case input for SAM and the index including 2026 in a sensitivity analysis.