SUMMARY

Generalized linear model (GLM) was used to standardize the CPUE for northern Atlantic albacore (Thunnus alalunga) caught by Taiwanese longline fisheries during 1968-1998. Three sub-areas, based on nominal CPUEs of the main species caught were defined. Sub-area 3, where non-albacore-directed efforts have increased recently, is not the traditional albacore fishing ground. The CPUE trends, which were derived from including or excluding the data of this sub-area, were estimated and compared. The standardized CPUE trend, estimated from the dataset including Sub-area 3, indicated that: (1) CPUE appeared to decline sharply at the beginning of the fishery (early 1968 to 1971), but it remained quite stable until the early 1990s; (2) CPUE trend appeared to decline since 1992. The CPUE series, estimated from the dataset excluding Sub-area 3, showed that: (1) although i