CPUE standardization of swordfish (Xiphias gladius) caught by Taiwanese large-scale longline fishery in the Indian Ocean

This paper briefly describes historical patterns of swordfish catches caught by Taiwanese large-scale longline fishery in the Indian Ocean. The cluster analysis was adopted to explore the targeting of fishing operations. In addition, the delta-inverse Gaussian generalized linear models were selected to conduct the CPUE standardizations of swordfish caught by Taiwanese large-scale longline fishery. The results indicate that the catch rates of the positive catches and the opportunity of catching swordfish might be determined by the position of fishing operations in areas other than Area SW and might be influenced by the targeting of the fishing operation in Area SW. The standardized CPUE series revealed different trends by areas, they slightly decreased in northern areas (NW and NE) and increased in southern area (SW and SE) in recent years.