Using your sonar

Seeing Your Lure on Sonar: Jigs, Spoons and Downrigger Balls

Why you can (and cannot) see your lure

Sonar sees anything that reflects sound back to the transducer. Metal, dense plastic and lead reflect well. A light soft plastic on a small hook reflects very little. Two other factors matter as much as the lure itself:

• Position. The lure has to be inside the sonar cone. Straight down under a stationary boat is ideal. A lure 50 feet behind a trolling boat is not in the cone at all.
• Size relative to settings. At low sensitivity or on a wide zoomed-out range, a small jig may be too small to register as more than a speck.

What a lure looks like on 2D sonar

Falling jig

On a scrolling 2D screen, a jig dropped from a stationary boat shows as a line slanting down from the surface. The slant is there because the screen scrolls sideways while the jig sinks. A fast-sinking spoon makes a steep line; a slower jig makes a flatter one.

Jig at depth

Once the jig is down and you start working it, it appears as a wavy or zigzag line at that depth, rising and falling with each lift. If you hold it still, it becomes a flat line. Watching that line is how you confirm your bait is just above the fish you marked.

Fish responding

The moment many anglers learn to love sonar is watching a fish mark rise off the bottom toward the jig line. The two lines meet, then you feel the bite. On 2D, a fish moving toward the lure usually shows as a mark angling up toward the jig line.

Downrigger balls on sonar

Downrigger weights are heavy, dense and hang almost straight down, usually just behind the boat. Because they stay near the transducer cone, they draw a consistent line across the screen at their set depth. A few practical points:

• The ball line confirms your counter is accurate. Line angle from current and speed means the ball often rides higher than the counter says, and the sonar shows the real depth.
• If the ball line disappears at speed, the ball has blown back out of the cone, which is a cue to slow down or add weight.
• Seeing fish marks rise toward the ball line tells you fish are interested in that depth.
• A transducer mounted near the stern sees the balls better than one mounted farther forward.

On a flasher

Flashers display sonar on a circular dial in real time. Instead of scrolling, the lure appears as a thin band at its current depth and moves up and down as you jig. Fish appear as wider bands that move toward or away from it. Ice anglers rely on this because it shows a lure and fish interacting without the scroll delay. Many fish finders offer a flasher-style mode or an ice mode that mimics this display.

The trick with flashers is gain (sensitivity). Too little and your jig disappears; too much and the dial fills with clutter. Many anglers set it so a small jig shows as a clean, thin band, then leave it there.

On down imaging

Down imaging can show a lure as a thin bright line or a small bright dot, but it is not as reliable as 2D for watching bait move. Down imaging is better at showing what the lure is near: brush, rock, weed tops. Many anglers run a split screen with 2D on one side and down imaging on the other for this reason.

Settings that make your lure easier to see

1. Use a higher frequency or narrow beam. A narrower cone focuses on what is directly under you and separates the lure from nearby fish and structure.
2. Zoom or bottom lock. Zooming into the bottom 10 or 20 feet enlarges everything in that band so a small jig line becomes visible.
3. Increase sensitivity a notch. Small lures may need more gain than you use for general cruising. Lower it again if clutter appears.
4. Raise ping speed and scroll speed when jigging so the screen updates quickly enough to show lure movement.
5. Turn off fish symbols. Fish ID icons hide the raw returns that show your lure. Use raw arches and lines instead.
6. Stay over the bait. GPS anchoring or careful boat control keeps the lure in the cone. Drift and the lure slides out of view.

Common reasons your lure vanishes

The boat moved

Even slight drift moves the cone off your lure, especially in deep water where the cone is wider but your line angle is steeper. Use a spot-lock trolling motor, anchor, or keep the line vertical.

The bait is too light

A soft plastic on a small hook may be invisible regardless of settings. A heavier jig head or adding a weight helps.

You are on a wide cone in shallow water

A wide cone in shallow water covers a small area anyway, but it also picks up weed, brush and bottom returns that can mask a small lure.

The lure is behind the boat

Trolled lures without a downrigger ride well behind and often wide of the boat. Traditional sonar will not see them. Side imaging may sometimes show a lure trailing out to the side, but it is not reliable.

Bottom line

Your sonar can show your bait clearly in the right conditions: vertical jigging from a stationary boat, a downrigger ball under the stern, or an ice jig under a flasher. Narrow the beam, zoom in, nudge sensitivity up and turn off fish symbols. If you still cannot see your lure, it is probably too light or outside the cone.