Northwest Arkansas Democrat-Gazette
Interpreting depthfinder images improves success
So many times I’ve wondered about long, solid lines at the bottom of my depthfinder screen, and now I finally know.
Wednesday, during a
commercial break on Ray Tucker’s Arkansas Outdoors,
It’s a Natural radio program on KABZ-FM, 103.7, co-host Mark Hedrick showed me a photo on his phone of Matt Hedrick’s Lowrance electronic graph. It showed the same long tapered line I’ve seen a thousand times.
It was a sonar image of a vast wad of largemouth and white bass at Lake Maumelle.
Matt, Mark Hedrick’s son, caught a few 3-pound largemouths out of the school on a spoon, but he also missed a bunch of short strikes.
Hoping to hook bigger largemouths, Matt switched to a light crappie jig. A white bass hit it, and he caught 32 whites in short order.
A big school of fish can be anywhere in the water column, but I often graph them near the bottom. The graph image is a long, thick line that tapers sharply. It reflects a sonar return off a school of fish so big and so dense that it appears solid.
I often see long diagonal streaks stretching from the horizontal line almost to the surface. Those lines are fish either going to or coming from the school.
The first time I really noticed them was New Year’s Eve 2008 on Lake Hamilton, when I fished for stripers and hybrids with a friend. We dropped spoons to the bottom, and the spoons were visible on the graph.
Streaks appeared on the graph, and when they collided with the sonar impression of the spoon, a strike occurred. It was like a living version of a video game.
Now that I’ve connected all the lines, so to speak, I have a better idea of how to interpret them in the future. More to the point, I have a better idea of how to fish them.
A couple of years ago I rigged up my Ascend FS12T kayak with a Lowrance Elite 4X graph, along with a custom mount that held a trolling motor on one side and the depthfinder transducer on the other. I built the contraption of discarded wood from a home improvement store and spare leg segments from a deer feeder.
A buddy at a local motorcycle custom shop bent the steel to 33-degree angles, and I bolted the wood to the steel. I built a bracket for the transducer and its wires from PVC. The whole thing slides into the kayak’s rod holders.
The first time I used it was on Huckleberry Lake near Russellville. As I cruised across the lake, my graph showed big wads and streaks everywhere. It looked like the lake was alive with fish.
I stopped the motor, dropped an anchor, grabbed a rod and looked at the graph. The screen was blank except for some surface distortion, and the depth and temperature readings.
I was puzzled. I wondered if throwing the anchor cleared out the fish.
I pulled in the anchor, stowed the rod and turned on the motor. The screen came alive again, and again it went blank when I stopped to fish.
It happened over and over, and I concluded that something was wrong with my unit.
Gary Hubble of N.I.F.E. Marine in Sherwood almost choked from laughing when I told him about it. This happens a lot. Hubble said the problem was electronic interference from the trolling motor causing false returns.
It’s a common problem, especially among anglers who have new electronic graphs and old electric motors. Newer motors have insulators to reduce electronic crossover.
Exacerbating my situation was that the transducer and motor are so close together.
I got a newer Minn-Kota on sale last year. It has the same amount of thrust as my old Minn-Kota, but it’s smaller and lighter. It’s ideal for a kayak, but Hubble warned that its proximity to the transducer might still corrupt the return signal.
In other words, the graph might never work right on a kayak as long as the motor is running.
Edwin Evers, who won the Bassmaster Classic earlier this month on Grand Lake O’ the Cherokees in Oklahoma, said Wednesday that electronics were vital to his victory.
His graph scans so far to the sides that he saw bass in clear water that would have spooked if he got close.
Instead, he stayed far enough away that they weren’t aware of him, and he caught a mess. Nearly 30 pounds, to be exact.
In the old days, he would have been lucky to catch one fish out of such a place.