What do Small Fish Look Like on Sonar On June 17, 2013

You may ask yourself - what do small fish look like on sonar?  It is not an easy answer. Sonar determines size as echo strength and displays echo strength as different colors and how thick the fish arch is. Echo strength is different from targets at 5 feet or 20 feet from the transducer because sound get weaker as it travels through water. This is why auto sensitivity turns the sensitivity higher in deeper water. I have some examples of perch on this tutorial. 

The first screen shot is a lake with suspended small fish about 5 feet with the water depth 20-30 feet.



This screen shot shows what the small fish look like on sonar in shallow water.






The last screen shot is from a different lake and shows fish (walleyes 1-4 lbs) and a sinker and a 5 inch creek chub (minnow). The sinker is 2 feet from the minnow. As I lift the sinker, the minnow follows and the same happens as I drop the sinker. The walleyes also followed the minnow up and down.  

The important point is the display size of a 5 inch minnow vs. the walleyes in 24 feet of water. On this screen shot compare the amount of yellow in the minnow and the thickness of the arch to the walleyes. There is not much difference in how the sonar displays the minnow and the walleye. 


by Bruce Samson under lowrance lowrance sonar

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