Standardization of albacore CPUE by Japanese longline in the Indian Ocean which includes cluster analysis

Standardizations of Japanese longline CPUE for albacore in the Indian Ocean regions were conducted. The models incorporated fishing power based on vessel ID where available, and used cluster analysis to account for targeting. The variables year-quarter, vessel ID, latlong5 (five degree latitude-longitude block), cluster and number of hooks were used in the standardization. The numbers of clusters selected varied among regions, but in all cases were either 4 or 5. Dominant species differed by cluster. The effects of each covariate differed depending on region. The CPUEs trends were decreasing during the early period, and constant or increasing after that.