Updating of standardization of bigeye tuna CPUE by Japanese longline fishery in the Indian Ocean

Standardization of bigeye tuna CPUE up to 2021 by Japanese longline fishery in the Indian Ocean was conducted using the Generalized Linear Model (GLM) with lognormal error structure. Cluster analysis was conducted before standardization, and cluster number was used for main effect as well as year, quarter, vessel ID and five degree latitude/longitude block. Area definition is the same as that for 2019 IOTC bigeye tuna stock assessment. CPUEs show decreasing trend from early 1980s to late 2000s, and then CPUEs show increasing trend. The trend of CPUE was usually similar to that in the previous study.