Correlations between environmental factors and CPUEs of blue marlin (Makaira mazara) and striped marlin (Kajikia audax) caught by Taiwanese longline fishery in the Indian Ocean

This study investigated the correlations between environmental factors (Indian Oscillation Index, Dipole Mode Index, Southern Oscillation Index, sheer currents, amplitude of the shear current, thermocline depth, and temperature at depth of 15/55m and temperature gradient at depth of 15/55m) and nominal CPUEs of blue marlin and striped marlin caught by Taiwanese longline fishery in the Indian Ocean. The results clearly showed that there are significant cycle-patterns between CPUEs and most environmental factors. In addition, this study also suggested the environmental factors with the time-lags for CPUE standardization analyses of blue and striped marlins in the Indian Ocean.