Section outline

  • 　The acoustic profiler is a moored fish finder. It is battery operated and data is stored on internal media. The device is placed on the seafloor facing upward and emits ultrasonic waves upward at regular intervals to record echoes. A CT meter (a machine to measure water temperature and salinity) and a depth gauge are also installed on the frame of the device to collect environmental data at the same time.




    Unlike ship-based measurements, this system can visualize underwater information continuously 24 hours a day for a long period of time, making it possible to study the diurnal behavior of organisms, seasonal differences in echoes, and echograms caused by changes in water temperature and salinity. The acoustic profiler used in this study has two frequencies, 38 kHz and 200 kHz. The instrument was originally intended for monitoring fish species at the margins of glaciers in Greenland under the ArCSII project. Since we are unable to visit the site due to the coronal disaster, we are using it in Sunahara-cho, near the Hakodate campus, as a practice run.





    Below is an acoustic profiler used in another field.