Standardized CPUE of Pacific saury (Cololabis saira) caught by the Chinese Taipei stick-held dip net fishery up to 2021

Catch and effort data of Pacific saury for the Chinese Taipei saury fishery in the Northwestern Pacific Ocean were collected from 2001-2021. Two alternative approaches, generalized linear models (GLMs) and generalized additive models (GAMs), were used to standardize the catch per unit effort (CPUE) of Pacific saury. An updated version (incorporating 2021 data) of the previous year’s CPUE standardization data set derived from fishing logbooks was used in this study. Most of the main explanatory variables and interaction terms used in the modeling analyses were statistically significant in the GLMs and GAMs. We suggest using the standardized CPUE series of Pacific saury derived from the GAM as basic input data in stock assessments, because this approach had a lower Bayesian information criterion, explained more deviance, and demonstrated better performance in the cross-validation tests than the GLM approach. The standardized CPUE of Pacific saury for the Chinese Taipei saury fishing fleets showed a general oscillating trend with a slight increase observed from 2001-2010, followed by a sharp increase through to 2014, a sharp decline until 2017, a dramatic increase in 2018, and then an abrupt decrease to 2021.