||The nominal bigeye CPUE was ranged between 4 no./ 1000 hooks and 9 no./ 1000 hooks in the tropical and whole Indian Ocean. As for the standardized CPUE series, they showed very similar trend with the nominal CPUE except after 2005 in the whole Indian Ocean. In 2012, the CPUE increased to the peak since lots of fishing activities occurred in the Somalia area. Before 2007, the nominal yellowfin CPUE was ranged between 2 no./ 1000 hooks and 5 no./ 1000 hooks in the tropical and whole Indian Ocean. After that, the nominal yellowfin CPUE continually dropped to the historical lowest CPUE of 1 no. / 1000 hooks. And then came back to the level of 2 no. / 1000 hooks in 2012. As for the standardized yellowifin CPUE series, they showed very similar trend with the nominal CPUE except before 1986. The treatment of target species proxy is considered as a crucial part in CPUE standardization. The information of number of hooks per basket seems not to be a proper target species proxy since there is a clear proportional relationship between the number of hooks per basket and the theoretical depth based on the observer data which collect from 2002.