Figure 8. Changes in the mean school depth in a period of 14 minutes, from 25-30 m (left panel) to ca. 10 m (right panel). Fish school had a mean depth of about 25-30 m when observed with a 10-degree tilt (02:02 UTC), and 14 minutes later (02:16 UTC) fish were closer to the surface at ca. 10 m depth using the sonar with 5-degree tilt.
