Standardized CPUE for the autumn cohort of neon flying squid caught by Japanese squid jigging fishery in the North Pacific from 2005 to 2025

We standardized the catch per unit effort (CPUE) of the autumn cohort of neon flying squid (Ommastrephes bartramii), based on the logbook from the Japanese squid jigging fisheries in the North Pacific during the summer between 2005 and 2025. The cohort was defined as individuals caught in areas east of 170°E longitude. Generalized additive models (GAMs) were applied to standardize the nominal CPUE, incorporating temporal (year and month) and spatial (longitude and latitude) variables. The model with the lowest AIC value was selected as the best performing model. The annual standardized CPUE derived from the best GAM showed a similar trend to the nominal CPUE. The standardized CPUE increased since 2023, and the highest CPUE value of the study period was recorded in 2025. This standardized CPUE can serve as a fishery-dependent abundance index in future stock assessments of this species.