Abstract
The blue shark Prionace glauca is the main bycatch species of the French swordfish-targeting longline fishery operating in the south-west Indian Ocean. Using observer and self-reported data collected aboard commercial longliners between 2007 and 2024, we present a standardized CPUE series for blue shark bycaught in this fishery estimated with a lognormal generalized linear mixed model (GLMM) to be used for the upcoming stock assessment. We propose to use the standardized CPUE for the period comprised between 2011 and 2024 where the monitoring effort has been consequent in comparison with previous years. Throughout 2011-2024, the standardized CPUE for the blue shark shows a slight decreasing trend, more precisely a substantial decrease between 2011 and 2019 followed by a stabilization since 2019.