Joint CPUE standardization of the Pacific saury in the Northwest Pacific Ocean by using the spatio-temporal modelling approach

Reliable indices of population abundance are an important type of data for stock assessment. We applied a Vector-Autoregressive Spatio-Temporal Model (VAST) to conduct index standardization by using the joint CPUE (catch-per-unit-effort) data of the Pacific saury in the Northwest Pacific Ocean between 1994 and 2023. The results indicated that the annual standardized CPUE trend had a fluctuated pattern over the studied periods, and the annual standardized CPUE value in 2023 was slightly increased compared to 2022. The analysis we presented is generally applicable and should be considered as a standard tool in the CPUE standardization.