Angling technology has gotten increasingly powerful in recent years. Newly developed forward-facing sonar (FFS) units now give anglers the ability to pinpoint the location and watch the behavior of fish in real time, a seemingly massive advantage. This has led to considerable concerns that new technology could provide an unfair advantage to anglers, making overfishing more likely. However, there has been little research on what the actual effect of FFS is on angler catches or how it influences angler behavior.

Researchers at the Center for Limnology set out to answer this question during a summer-long angling experiment led by incoming PhD student Max Wilkinson, Wisconsin DNR scientist Greg Sass, and CFL scientists Zach Feiner and Olaf Jensen. Two teams of two undergraduate technicians fished for smallmouth bass on Nebish Lake in Vilas County nearly every day from the end of May through August of 2025. During the first half of the summer, one team got to use FFS while the other fished without technology. The teams swapped halfway through, tracking their catch rates and fishing locations via GPS.

After fishing for a combined 512 hours (equivalent to fishing 24 hours a day for three weeks straight) and catching 1,722 smallmouth bass, the results came in – using forward-facing sonar technology actually lowered catch rates. On average, teams caught about 2.5 fewer fish per day using FFS compared to fishing without it. Using FFS did allow anglers to catch slightly larger fish, by slightly less than 1 inch, although we will let readers decide whether that tradeoff is worth it.

So why did FFS affect catch and size? It seems that it influenced angler behavior. While using FFS, anglers covered less distance, moved slower, and turned at sharper angles, consistent with using the technology to actively search for and target individual fish. They also fished in different places on the lake. With FFS, anglers tracked potentially larger fish in deep, mid-lake areas, while without it, anglers tended to target more easily visible habitats along the shoreline. That extra time spent searching seems to have led to fewer chances of catching fish than if anglers had just kept their lines in the water.

Overall, these results might indicate that forward-facing sonar does not pose a significant risk to fisheries, but the research team is planning another experiment this summer to see whether the technology impact is different when targeting other species. For now, as the authors suggest in the paper, “the strongest effects of FFS may indeed be on the anglers themselves, rather than the fish.”

Read the paper here.