Japanese longline CPUE for yellowfin tuna in the Indian Ocean standardized by generalized linear model

Japanese longline CPUE for yellowfin tuna in the Indian Ocean (area aggregated and area-specific) was standardized up to 2019 by GLM based on similar methods used in the previous studies. Basically, standardized CPUEs showed similar trends among areas. CPUE continuously decreased from 1950s to around 1974, and kept in the same level until 1990. Thereafter, it declined to a historically low level and then slightly increased in recent years. Difference of CPUE was small by removing northwest area, but large difference was observed between subarea and five degree blocks for the effect of fishing ground.