A Full Summer of Data Says Forward-Facing Sonar Might Be Working Against You

Forward-facing sonar promises to show you exactly where the fish are sitting before you ever make a cast. A field experiment on Nebish Lake in Wisconsin spent an entire summer testing whether that promise actually turns into more fish in the boat, and the result came back backwards. Researchers from the University of Wisconsin's Center for Limnology, working with Wisconsin DNR scientists, put two teams of undergraduate research technicians on the lake, in Vilas County, from the end of May through August 2025. One team fished with forward-facing sonar (FFS), the other fished without it, and partway through the summer the teams swapped setups so everyone fished both ways. Over 512 hours on the water and 1,722 smallmouth bass landed, the team running FFS caught roughly 2.5 fewer fish per day than the team fishing blind to what was under the boat.

The Size Trade-Off

It wasn't a total wash for the sonar team. Smallmouth bass caught using FFS ran slightly less than an inch bigger, on average, than fish caught without it. The technology didn't fail outright, it traded volume for size.

How Sonar Changed the Way Anglers Fished

The more interesting part isn't the fish, it's what the anglers did differently. Teams using forward-facing sonar covered less distance, moved slower, and turned at sharper angles than the team without it. They also fished different water, gravitating toward deeper, mid-lake areas instead of working the shoreline the way the non-sonar team did. As the study's authors put it, "the strongest effects of FFS may indeed be on the anglers themselves."

The Catch

This is one lake, one species, and two teams of undergraduate techs who fished nearly every day for a summer. It's also just smallmouth bass. The research team is already planning a follow-up experiment to see whether the same pattern holds for other species, which tells you they don't consider this settled either. One study on one lake isn't a verdict on forward-facing sonar as a category.

What This Means on the Water

I don't own forward-facing sonar. My bass setup is still my dad's old Shimano rod and Rapalas, which says more about sentiment than strategy, but it also means I've never had a screen to stare at while I'm supposed to be fishing. Reading this, I'll admit what surprised me wasn't that FFS anglers moved slower, it's that slower and more deliberate turned out worse, not better. I'd have guessed that watching exactly where a fish sits would only add information, never cost you anything. This study says that's not automatically true. My honest read, and this is my extrapolation, not the study's, is that a screen can pull your attention away from the parts of fishing that were already working, the water you'd normally cover, the shoreline you'd normally hit on instinct. If you're deciding whether an FFS unit is worth the money, or you already own one and results have been mixed, a side imaging or down imaging fish finder is a different, cheaper piece of the same puzzle worth understanding before you spend more on electronics. This is one summer on one lake, and it's a reason to actually track your own numbers before assuming new technology is doing what it's supposed to.

Citation

Wilkinson, M. V., Ball, K. D., Duvall, J. D., Pickhardt, A. O., Wilson, B. J., Feiner, Z. S., Jensen, O. P., & Sass, G. G. (2026). Screen time: Forward-facing sonar changes angler behavior and increases fish capture length, but decreases catch rates for smallmouth bass in a randomized controlled experiment. Fisheries Research, 297. https://doi.org/10.1016/j.fishres.2026.107710