CPUE standardization of Pacific saury (Cololabis saira) for the Chinese Taipei’s stick-held dip net fishery in the Northwestern Pacific Ocean from 2001-2017

The catch and effort data of Pacific saury for the Chinese Taipei’s stick-held dip net fishery in the Northwestern Pacific Ocean were collected from 2001 - 2017. Two alternative approaches, generalized linear models (GLMs) and generalized additive models (GAMs), were applied to standardize the catch per unit effort (CPUE) of Pacific saury, with an assumption of lognormal error distribution. In this study two data sets were used: 1) an updated version (incorporating 2017 data) of the previous year’s CPUE standardization data set derived from fishing logbook data collected on a daily and vessel basis, and 2) an aggregated data set derived from logbooks, but assessed at a 1.0° square grid resolution and averaged by month. Most of the main explanatory variables and interaction terms used in the modeling analyses were statistically significant. The results derived from both approaches, GLMs and GAMs, were almost identical. Standardized CPUE of Pacific saury for the Chinese Taipei’s stick-held dip net fishery in the Northwestern Pacific Ocean showed a general oscillating trend with a slight increase observed from 2001 - 2010, followed by a sharp increase through to 2014, and then a sharp decline until 2017.