Live-imaging sonar, the real-time screens that let bass anglers watch fish and lures underwater, does help pros catch more fish, a new Maryland Department of Natural Resources study found. On the tidal Potomac River, though, the technology made no measurable difference.
DNR biologists Ryan Gary and Joseph Love, working with Steven Bardin of Major League Fishing, analyzed eight of the league’s 2025 Bass Pro Tour events, which drew 73 professional anglers. Their paper, “Influence of live-imaging sonar on black bass catch,” appears in the North American Journal of Fisheries Management, and DNR summarized the results Oct. 9.
The tournaments gave researchers something close to a natural experiment. Under the league’s rules, anglers could use live-imaging sonar during only one of each day’s three competition periods. That let the team compare the same anglers, on the same water and the same days, fishing with and without the screens.
Where the screens mattered
Overall, live-imaging sonar significantly increased catch rates, but the effect depended on the fishery. The biggest gains came on Lake Conroe in Texas and Lake Murray in South Carolina, both large reservoirs. On the Potomac River and on Alabama’s Lake Guntersville, researchers found no statistical advantage in average catch rates.
Depth and cover explain much of the difference. A greater share of bass was caught with the sonar in deep, open water with little cover, and anglers catching fish deeper than 9 feet were nearly three times as likely to be using it. In shallow areas with abundant grass, wood and other structure, the technology was used less and helped less. That describes much of the tidal Potomac, where bass anglers typically work grass beds and shoreline cover.
The screens did not produce bigger fish. Average bass size generally did not differ between periods with and without the sonar.
A Charles County connection
The Potomac data came from Southern Maryland water. Major League Fishing’s 2025 Bass Pro Tour stop on the Potomac ran June 26–29, 2025, with daily launches from Smallwood State Park in Marbury, in western Charles County near Mattawoman Creek.
For local tournament and recreational anglers who fish the river from Smallwood and other Charles County ramps, the result suggests that on the Potomac’s shallow, grassy water, conventional skills and local knowledge still count for as much as the newest electronics.
Why managers are watching
Live-imaging sonar lets anglers see individual fish and their own lures in real time. Anglers, tournament organizers and fisheries managers have raised ethical concerns about whether it gives anglers too much of an edge and what it could mean for fish populations, according to DNR.
The authors concluded that the sonar offers limited advantage in shallow, complex shoreline habitat, but that the risk of overharvest may be higher in deeper, less structured waters or when fish suspend in open water seasonally. They recommended that managers weigh water body shape, depth and habitat when evaluating the technology. DNR also noted that if more fish are caught from deeper water, careful handling and release become more important, because fish pulled up from depth can be more easily injured.
DNR did not announce any rule changes tied to the study. Anglers looking for current conditions on the Potomac and Patuxent can follow the Chronicle’s weekly Maryland Fishing Report and recent coverage of the fall bite in Southern Maryland waters.
