One thing I have learned while using SI is how to determine fish size. Crappie on SI don't reveal a large return because they are a small fish (of course) but also because of their shape. If you think about SI and how it is a thin beam that when objects are scanned they return a signal. I try to think about it this way.. Think about a water fall of smooth flowing water. If you stick a football (representing a striped bass) in the waterfall you will make a pretty big hole in the wall of water. If you stick a frisby vertically (representing a crappie) in the waterfall you will have much less of a return due to the thickness and shape. I believe the same holds true to fish size and returns on SI. The football size thick fish will return a larger round dot and cast a nice shadow in SI. The vertical frisby shaped fish will return a much smaller dot and small shadow (if any). Just something to keep in mind. Also remember to compare size to scanned distance. If you are scanning 100 feet, your returns will be much smaller than scanning at 50 ft.

Gar seem to return a long return since they are long hard fish. Catfish seem to return your biggest and brightest returns since they are long, hard, and FAT!.

Below are some examples of fish type. Most of these are confirmed by catching them. The gar images are confirmed by visually seeing them rolling all across the surface. The catfish images have not been confirmed but I feel pretty sure about them.

Striped Bass









Gar











Crappie













Catfish







DoubleG