CPUE standardization of striped marlin (Tetrapturus audax) caught by Taiwanese large scale longline fishery in the Indian Ocean

This study aggregated and analyzed catch, effort and length data of striped marlin caught by Taiwanese large longline fisheries in the Indian Ocean and conducted CPUE standardization for striped marlin for 1979-2020 and 2005-2020. This paper briefly describes historical patterns of fishing operations and striped marlin catches caught by Taiwanese large scale longline in the Indian Ocean. The groups of data sets derived from cluster analysis based on species compositions were incorporated in the CPUE standardization models as a covariate for explaining the target to obtain the relative abundance indices for further stock assessments. Except for the delta-lognormal models, the standardized CPUE series obtained from different model assumptions revealed similar trends.