Humminbird 561 - Manual (Page 60)

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Fish ID+™
Settings: Off, On; Default = On
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 Single Beam models (550, 560), targets detected in the 200 kHz
beam are represented as shaded fish symbols.
• In DualBeam PLUS™ models (561, 570), targets detected in the
200 kHz narrow beam are represented as shaded fish symbols, and
targets detected in the 83 kHz wide beam are represented as hollow fish
symbols.
• In Down Imaging™ models (570 DI), targets detected in the 455 kHz
conical beam are represented as shaded fish symbols, and targets
detected in the 200 kHz conical beam are represented as hollow 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.
Narrow Beam
Shaded Fish Symbols
Wide Beam
Hollow Fish Symbols
Sonar Menu Tab