Echogram illustrating the ascending and descending phases of the diel migrations through the water column. The downward and upward migration activity occurs during crepuscular periods. The color scale maps to acoustic scattering intensity.
Water Column Echogram
Image courtesy of DEEP SEARCH - BOEM, USGS, NOAA. Download larger version (jpg, 365 KB).

Echogram illustrating the ascending and descending phases of the diel migrations through the water column. The downward and upward migration activity occurs during crepuscular periods. The color scale maps to acoustic scattering intensity.

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