Clear Spring angler Garrett Davis recently caught a 16-year-old tagged muskellunge, known as Fish 691, from the non-tidal Potomac River on January 4, marking the first time the fish was captured by an angler since Maryland Department of Natural Resources biologists began tracking her in 2013. The recapture highlights the longevity, elusiveness, and resilience of muskies in Maryland’s sole self-sustaining population of the species.
Fish 691, a female muskellunge, has been monitored through DNR’s tagging and telemetry efforts for more than a decade, providing rare insights into the life history of an apex predator in a heavily fished stretch of the Potomac. Muskellunge, often called muskies and nicknamed “the fish of 10,000 casts,” occur in low densities and draw dedicated anglers to the river’s non-tidal sections from Seneca in Montgomery County to Cumberland in Allegany County.
DNR’s Freshwater Fisheries Program has tagged 1,011 muskies in the Potomac since the late 1990s to track growth, movement, and exploitation rates. Of those, 466 have been reported recaptured, yielding a 46 percent recapture rate. To safeguard the population, DNR advises against targeting muskies when water temperatures reach or exceed 80 degrees Fahrenheit.
Fish 691’s documented history began in March 2013 during an annual electrofishing survey, when biologists inserted external dart tag 2414 into the then 30.25-inch female. Two years later, in March 2015, she was recaptured in the same general area at 36.5 inches. In March 2017, during the start of a radio-telemetry study, she was collected again, measuring 39.75 inches and weighing 15.5 pounds at age 7, based on anal fin ray analysis. Biologists surgically implanted a radio transmitter under anesthesia via electronarcosis, assigning her temporary identifier fish 950. Tracking that summer and fall showed she maintained a small, sedentary home range in pool habitat with minimal movement. The transmitter battery expired in winter 2017-18, and she went undetected until March 9, 2021.
That third recapture by biologists occurred when she measured 43.75 inches and weighed 20.75 pounds at age 11. A new, longer-life transmitter with extended detection range was implanted, and she became Fish 691. Weekly tracking in 2021 confirmed similar behavior: a restricted home range and limited seasonal shifts. A 2022 population estimate survey in her primary stretch, supported by Muskies Inc. grants, documented 7 to 11 adult muskies over 30 inches per river mile but did not recapture her despite intensive efforts.
Despite residing in one of Maryland’s highest-angling-pressure muskie zones, Fish 691 evaded hook-and-line capture for 16 years until Davis landed her. He noted the tag number, photographed the fish, and released it. “I was very fortunate to catch her,” Davis said. “And, it was awesome to hear the story behind her.”
The catch represents only the fourth documented recapture of Fish 691 and the first by an angler. Few of the 1,011 tagged Potomac muskies have been reported recaptured four times by anglers, underscoring the species’ wariness in a challenging riverine environment marked by floods, ice jams, droughts, high summer temperatures, and sustained fishing pressure.
Maryland maintains one true, naturally reproducing muskie population in the non-tidal Potomac, supporting a popular recreational fishery. Biologists supplement annual electrofishing with occasional telemetry studies, including larger transmitters funded by grants in 2018 and 2021 to examine summer habitat use in warmer waters. Angler cooperation through voluntary creel diaries and tag reporting has been essential to building long-term data on individual fish.
DNR encourages catch-and-release practices, proper fish handling, and adherence to temperature guidelines to sustain the resource. Anglers can find more details on the Maryland Muskie Program through the DNR website.
This recapture contributes to ongoing conservation in the Potomac watershed, which spans multiple Maryland counties including those in Southern Maryland near the tidal transition. While the non-tidal sections lie upstream, the river’s health affects downstream areas in Charles, Calvert, and St. Mary’s counties through shared water quality and migratory species dynamics.