Analysis on fishing strategy for target species for Taiwanese large-scale longline fishery in the Indian Ocean.

The cluster analysis approach was utilized to account for the patterns of the fishing strategy for target species for Taiwanese large-scale longline fishery in the Indian Ocean. The analyses were separately conducted for 4 sub-areas defined for the stock assessment for billfishes. For each sub-area, data from two different time periods of 1979-2020 and 2005-2020 were used. In general, the clustering approach was able to explicitly and clearly identify the targeting of each set. The cluster analysis suggested that main target species would be yellowfin tuna and bigeye tuna in the two northern sub-areas, while albacore and other species were the major targe species in the two southern sub-areas, with some bigeye tuna also included.