Japanese longline CPUE for bigeye tuna in the Indian Ocean standardized by GLM

Standardization of Japanese longline CPUE for bigeye tuna was conducted for 1960-2012 by using GLM (generalized linear model, log normal error structured). Methods of standardization are the same as or similar to those used at IOTC WPTT in 2012. The effects of season (month or quarter), subarea or LT5LN5 (five degree latitude-longitude block), SST (sea surface temperature), NHF (number of hooks between floats) and material of main line, and several interactions between them were used for standardization. The trend of CPUE slightly differed by area, but high jump in 1977 and 1978, slight decrease after that, and increasing trend in the recent few years are seen as for each area. Change in fishing gear (material of main line and NHF) was seen especially after 1990s, which may have caused the difference between nominal and standardized CPUE.