Fish Id - Humminbird 688ci HD DI Operation Manual

Fish ID+™ uses advanced signal processing to interpret sonar returns and will
display a Fish Symbol when very selective requirements are met. When a fish is
detected, a fish icon and its depth are displayed above the return that has been
classified as being a fish. Three different fish size icons represent the intensity of
the sonar return and provide an indicator of relative fish size.
In the 688ci HD, targets detected in the 200 kHz narrow beam are represented
as orange fish symbols and targets detected in the 83 kHz wide beam are
represented as blue fish symbols.
Orange Fish Symbols
In the 688ci HD DI, targets detected in the 200 kHz conical beam are
represented as orange fish symbols and targets detected in the 455 kHz conical
beam are represented as blue fish symbols.
In the 688ci HD XD, targets detected in the 200 kHz narrow beam are
represented as orange fish symbols and targets detected in the 50 kHz wide
beam are represented as blue fish symbols.
When Fish ID+™ is turned off, the Fishfinder shows only the raw sonar
returns on the display. These returns will often result in "arches" forming on the
display, indicating potential targets. Due to the transducer beam angle, the
distance to a fish decreases as the fish moves into the beam, and then
increases as it moves out again, creating a Fish Arch when this distance change
is shown on the display. Boat speed, chart speed, and the position of the fish
within the sonar beam greatly affect the shape of the arch.
Fish ID+™
Settings: Off, On; Default = Off
Narrow Beam
Transducer Cone and Fish Arches
Wide Beam
Blue Fish Symbols
117 Sonar Menu Tab