Unit Operation And The Chart; Understanding Sonar - Garmin Fishfinder 160 Blue Owner's Manual

On the Water On the Water
This fi sh is currently in a Dead Zone and is not detected
by the sonar. The fi sh is in the coverage area of the
transducer, but remember the fi rst strong return sets the
bottom level. The fi sh will never be detected since the
bottom level will never be set below the fi sh. The fi sh on
the right side of the display (shown in light grey) will be
detected and displayed when the transducer cone passes
over the fi sh.

Understanding Sonar