For a technology that has split competitive fishing down the middle, forward-facing sonar has been argued over with remarkably little hard data. A summer-long experiment in northern Wisconsin has now put a number on it, and the number ran the wrong way for the technology's boosters.
Two teams of experienced anglers fished Nebish Lake six days a week through the summer of 2025 in identical four-hour trips. For part of the study one team ran forward-facing sonar and the other did not. Later they swapped. Because the same anglers fished the same water under near-identical conditions, researchers could isolate the effect of the technology rather than differences in skill or local knowledge. Between them the teams logged close to 500 hours and caught more than 1,700 smallmouth bass.
Anglers using FFS caught roughly 0.64 fewer smallmouth per hour than when they fished without it.
Wired2Fish, which detailed the findings, noted that this was the opposite of what both the researchers and most anglers expected. The explanation the study settles on is unglamorous: screen time replaced fishing time. GPS tracking showed that with live sonar running, anglers covered less water and made more turns with the boat. Rather than casting continuously they slowed down, hunted individual fish on the display, and carefully positioned the boat before making a presentation.
The fish they did catch were bigger. Bass landed while using FFS averaged about an inch longer - a modest gap, but a statistically significant one. Researchers suspect the technology opens up summer smallmouth that move offshore to chase pelagic baitfish, water most anglers simply never fish. Maximum size, however, showed only a weak relationship with sonar use. The technology lifted the average, not the ceiling.
The study also found little support for the standard defence that catch rates climb once an angler learns the tool. More days on the technology did not translate into markedly better fishing over the course of the experiment.
On the question that matters most to regulators, the authors were direct: their results do not support proposed bans on forward-facing sonar based on fears that it dramatically increases catch rates. They were equally careful to say the argument is not finished. Other research has found increased catches of crappie and largemouth bass, and little or no effect elsewhere. Like most fishing tools, FFS appears to work differently depending on the fishery, the species and the angler.
Minnesota supplies the counterweight. A study in the journal Fisheries, conducted by the U.S. Geological Survey, the University of Missouri, the University of Louisiana and Memorial University of Newfoundland, estimated that Minnesota anglers harvest around 36,000 tons of freshwater fish a year - about 80 million pounds, more than double the official state estimate of 30 million pounds, which was last calculated in 2001. The state had already proposed cutting the walleye bag limit from six fish to four from 2027.
"We have been looking at harvest over time, and we don't see over-harvest generally as a problem," Brad Parsons, the Minnesota Department of Natural Resources fisheries chief, told the Star Tribune. "Even with the walleye bag limit change, this isn't a crisis we are trying to address. This is [...] to be good stewards and to be proactive."
What nobody disputes is the uptake. Bud Dusenka, of Frankie's Live Bait and Marine in Chisago City, told Outdoor Life that essentially every top-end boat the dealership sells now goes out with FFS fitted. "Everybody either wants it or adds it later," he said.
Terry Thurmer has run a harbour and boat launch on Mille Lacs Lake for more than 30 years and sees a few thousand boats a season. He estimates about a quarter now carry live sonar, and expects that share to grow. He does not think Mille Lacs - a big lake with already-reduced harvest limits - is at risk.
"But it will cause holy hell on smaller lakes," Thurmer said. "Guys can get on a little lake they've never fished before and find panfish right away."
That gap between a controlled smallmouth experiment and what a harbour operator watches happen on small water is exactly the space the next round of research has to fill. A University of Minnesota team has launched a three-year, $676,000 project surveying Minnesota anglers on how they use FFS, comparing success against traditional sonar across both open-water and ice seasons, and modelling whether live imaging could deplete populations over time. Researcher Cam Mosley told MPR News the point is to hand fisheries managers better data before they write new rules.
The tournament world has not waited. The National Professional Fishing League bans FFS outright in competition. Major League Fishing and Bassmaster have both tried to satisfy each camp with rules limiting when and where it can be used during 2026 events. Musky tournaments banned it early; walleye and crappie circuits allow it without restriction.
Professional bass angler Mark Daniels Jr., who fishes the MLF circuit, argued in a 21-minute video this June that forward-facing sonar has ruined tournament bass fishing - a fair-chase objection rather than a fisheries one. It is a distinction the Wisconsin study cannot settle. Whether live sonar puts more fish in the boat is now a measurable question with at least one clear answer. Whether it belongs in competition never was.