Correlation curves between specimen number to be collected and chlorophyll (A: μg/L) and oxygen (B: μmol/kg) concentrations in each of 15 stations in the Indian Ocean during KH-10-05. A: Pearson's correlation test: r = 0.867, p b 0.001; B: r = 0.880, p b 0.001; Groups 1 and 2 are inside and outside the circle, respectively.