CPUE standardization of yellowfin tuna caught by Korean tuna longline fishery in the Indian Ocean, 1977-2017

In this study we standardized CPUE of yellfowfin tuna caught by Korean tuna longline fisheries in the Indian Ocean using Generalized Linear Models (GLM) with operational data. The data used for the GLMs were catch (number), effort (number of hooks), number of hooks between floats (HBF), fishing location (5° cell), and vessel identifier by year, quarter, and region. We applied cluster analysis to address concerns about target change through time which can affect CPUE indices. The CPUE was standardized using lognormal constant and delta lognormal approaches, considering with vessel effects and without vessel effects, and the main indices was estimates from delta lognormal approach.