STANDARDIZED CPUE OF SWORDFISH (XIPHIAS GLADIUS) CAUGHT IN THE TAIWANESE LONGLINE FISHERY IN THE SOUTH ATLANTIC OCEAN FOR 1967-2012, ADDRESSING THE TARGETING CHANGE

SUMMARY Catch and effort data of the Taiwanese distant-water tuna longline fishery in the South Atlantic Ocean were standardized for swordfish (Xiphias gladius) by applying generalized linear models (GLMs). Two periods (1967-1989 and 1990-1999) and the information on operation type (the number of hooks per basket, HPB) from 2000 were considered in the standardization of CPUE (catch per unit effort) to address the issue of targeting change of this fishery. All the predictor variables, including time, fishing area, and gear configuration were statistically significant. The standardized CPUE of swordfish for 1967-1989 and 1990-1999 were almost identical to the results based on an entire period (1967-2012). However, the relative abundance indices in the late 1990s were sensitive to the inclusion of HPB in the model. In general, the standardized CPUE of swordfish in the South Atlantic Ocean showed a decreasing trend from 1967 through 1990, with a sudden increase during 1991 to 1996, but dropped to a lower level in the late 1990s and slightly decreased from 2000 until 2012. RESUME