Fishing Near Drop Offs -- Catching Fish Near Drop Offs On June 04, 2013

We rarely see fish on drop-offs because the closest “bottom” to the transducer is the drop-off, so the fish are not displayed. Sonar displays the echo strength of the target and the distance the target is from the transducer. The first example has the fish a farther distance from the transducer than the bottom so the fish echo is added to the “bottom “echo and not seen. The “bottom” under the transducer is 25 ft, fish at 23 ft, and the drop off “bottom” is 20 ft. Now visualize what the sonar will show you. The picture is my rough drawing so it is not to scale; it is just to get you thinking.

I have only captured one recording like this so the conditions have to be perfect to really see what you are doing while fishing and catching fish near drop offs.

I am drifting very, very slowly on a sharp drop-off as I am fishing near the drop-off. Notice how flat the fish arch is. The drop-off is a fast taper and not a ledge. I think the reason you can see the fish in the dead zone is because of the sharp drop which causes less return from the bottom so it displays the bottom as red for echo strength. The fish echo is added to the bottom, so the fish arch is yellow when it is in the dead zone. On a slower drop-off, the “bottom” would return stronger echoes and it would be yellow, so the fish would not be displayed in the dead zone. The bottom is sand and I have never seen fish on the side before. The top was loaded with fish. I just think there were many fish so I got lucky capturing this recording.

The second example shows a fish in the dead zone.


by Bruce Samson under lowrance lowrance sonar

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