Perch, White Perch and Walleyes

Green Bay Small Fish and Walleyes Identifying fish size is difficult with traditional down looking sonar. Since 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.
Green Bay has schools of small fish near walleyes. The below example demonstrates them with the DownScan on the left using palette 7. The right side is traditional down looking sonar. The cursor marks the same location on each side.
I didn’t have my underwater camera along to identify them but I was lucky enough to catch them when I was trolling for walleyes. (Everything bites worms!) The only time I would catch the white perch and perch was when I found the large schools of small fish so I think they were the small fish schools. The fish photos are white perch and regular perch. I used my friends hand to demonstrate the white perch’s size and the ruler measured the perch at 7 inches.

I also found I could find these fish easily at 23 mph using sonar and DownScan.
The next example demonstrates small fish and walleyes on the same screen for comparison using the DownScan and regular sonar. The DownScan easily shows fish size in this example and it works well for this while looking for fish. Another point on identifying walleyes from perch is walleyes are usually not as numerous as perch so it is as simple as counting the dots on the DownScan. Larger and fewer dots equals walleyes.
Both DownScan and traditional sonar work well but I have found using the split screen I look at traditional sonar differently and it helps to solve the famous “what is that question”. Many times on the water I see something with sonar that I don’t understand and the DownScan helps me interpret sonar better since I get a different look at the target with the 2 views.