Understanding Fish on Sonar Posted on December 02, 2021

#1 Walleye fishing  

Side scan saved the day. the weed, sand and mud edges were easily seen. The little sand dip in the weeds is where we found walleyes. They were on the sand right next to the weeds.

No wind, clear water and sunny. Only bass shallow so we looked deeper and found some at 22 foot.

Top arrow is mud

2nd arrow is sand

3^rd arrow is weedlines

Bottom arrow is weed dip

#2 Pay attention to sonar.

We were using spot lock to cast for walleye and Levi said look at the sonar. I quickly reeled up and dropped my jig and caught a 4 lb largemouth bass. The 2nd photo is the bass swimming away after I released it.

#3 Fish in bait show up well.

Notice the 2 bright yellow arches (green arrow) in the red bait (black)

#4 Sonar in vegetation usually sucks.

I looked at lots of areas and didn't see any fish and caught fish. But here is one example where the fish showed up.

Fish in vegetation, you don't have to see fish to catch them. I often don't mark fish in weeds but still catch them like this one. I spotted the fish with my Aqua-Vu and dropped my bait near the camera!

Green arrow shows nice fish on down imaging but looks small on 2D. It is probably on the edge of the 2D cone and the DI cone is wider so shows the fish better.

Reason to run DI and 2D sonar. I also use Navionics on my Lowrance and LakeMaster on my Humminbird. DI (down imaging) is better in weeds most of the time.

#5 Difference in cones from different transducers.

My Garmin PS30 shows the distance to the side the fish are.

Green arrow 3 feet to the left of the transducer which is mounted on boat's mid-line.

White arrow 8 feet to left.

2D sonar only tells you how far off the bottom and that the fish in the cone somewhere.

#6

Red circle fish

Black arrow weeds

Green arrow small boulders on hard bottom point.

Blue arrow bait balls that create shadows on side scan.

This should help get started in interpreting your sonar.