Abstract: Catch and effort data of sailfish (Istiophorus platypterus) were collected and analyzed for the
Taiwanese distant-water tuna longline fishery in the Atlantic Ocean. Nominal CPUE based on
catch records in logbooks or that estimated using catch ratio of sailfish over the two species
(sailfish and spearfish Tetrapturus pfluegeri) were standardized using generalized linear models
(GLMs). Two separate eastern and western stocks of sailfish were considered in the analysis,
with information on operation type (i.e. hooks per basket) being included as a potential effect.
Relative abundance indices showed similar and consistent trends for the two assumed scenarios
on catch data. The standardized CPUE of eastern Atlantic sailfish increased from 2009 to a
higher level but then dropped in recent two years (2014-2015), while for the western stock the
CPUE showed a decreasing trend during 2010 and 2014, with a slightly increase in 2015.