| 英文摘要 |
This study aimed to explore the distribution patterns of size and CPUE of south Pacific albacore stock caught by Taiwanese longline fishing fleet. Results indicated that longline vessels may shift their target on different species after 1997，the actual year for shift major targeting exercises may be? occurred from 2001to2002. A cluster analyses based on catches of all species in each trip, and number of hooks appear to be an effective method for identify different targeting practices in the Taiwanese longline fishery operate in the region，and an identified and separated albacore CPUE series appears to be more representative of true situation。The CPUE trend for albacore after 1999 was stable or even slightly increased instead of a sharply decreased been seen in the mixed data set。A fishing practice of about 30% target on albacore, and 70% on bigeye seems maintained for the fleet after 2003. In addition, the temporal and spatial differences in mean measured length and mean back-calculated length were found inconsistence before 2002。And, age composition of the stock, which estimated based on the mean weight-converted length indicated that the fleet mainly target on ages 6-11 of the stock, the juvenile fish (age ＜=5) only accounted for about 3 to 10% of the catch. And, catch % of ages 6-7 was about 13.6-27.9% before 2007, but dropped to about 5.4-6.6% in recent two years. |
