Surface clutter
Fish arches 
Structure
In FasTrack, fish arches show as horizontal bars.
Bottom signal 
ColorLine
FasTrack bar graph
Sonar Page showing FasTrack.
Fish I.D. (Fish Symbols & Depths)
The Fish I.D. feature identifies targets that meet certain conditions as fish. The microcomputer analyzes all echoes and eliminates surface clutter, thermoclines, and other signals that are undesirable. In most instances, remaining targets are fish. The Fish I.D. feature displays fish symbols on the screen in place of the actual fish echoes.
There are several fish symbol sizes. These are used to designate the relative size between targets. In other words, Fish I.D. displays a small fish symbol when it thinks a target is a small fish, a medium fish sym- bol on a larger target and so on.
The sonar's microcomputer is sophisticated, but it can be fooled. It can't distinguish between fish and other suspended objects such as trotlines, turtles, submerged floats, air bubbles, etc. Individual tree limbs ex- tending outwards from a group of limbs is the hardest object for the Fish I.D. feature to distinguish from fish.
You may see fish symbols on the screen when actually, there are no fish. The reverse is also true.
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