Inferring species from differences in echoes of different frequencies

　Species are inferred from the difference between low-frequency and high-frequency echoes, and the inferred species are verified by other methods. For this purpose, we use actual fishing gear and remotely operated video (ROV). In the echogram below, the response seen near the seafloor only at high frequencies is predicted to be krill, and the response seen in the middle is predicted to be walleye pollock. The actual ROV can be seen at ・・・・