Michael A. Sawyers
The Maryland Fishery Service will continue meeting with the U.S. Army Corps of Engineers in an attempt to keep the North Branch of the Potomac River downstream of Westernport cool enough to support trout.
The trout population between Westernport and Pinto prospered enough during the first decade of the 2000s to support several outfitting/guiding companies targeting the rainbows and the browns.
The trout came from fingerling stockings.
Those fish, according to Ken Pavol, a retired state fishery biologist and the head of the local guide association, grew to 12 inches in one year and 15-18 inches the following year.
Then came the summer of 2010 and the combination of high air temperatures and low water releases from Jennings Randolph Dam.
“It didn’t wipe the trout out, but the impacts were significant,” said Don Cosden, director of freshwater fisheries for the Department of Natural Resources.
“Fishing success suffered and even trout that were caught were already stressed and that can cause mortality,” he said.
Cosden said his staff is attempting to show the Corps how much water needs to be released during certain air temperatures so that trout can survive.
“We have rough estimates that show the average temperature has to be below 25 C (77 Fahrenheit) during afternoon hours. To maintain that as far downstream as McCoole, releases need to be at least 150 cfs (cubic feet per second). To maintain it down to Black Oak, probably 200 to 250 cfs would be needed.”
Cosden realizes the Corps has other demands on the water in Jennings Randolph. A certain lake level has to be maintained to make boat ramps and a beach usable for example. He said he hopes to be able to eventually predict how much flow will be needed when meteorologists are saying a stretch of very hot weather is approaching.
Fishery biologists recently electrofished the river.
“I’d say we were somewhat surprised at the good numbers of brown and rainbow trout above Black Oak, though we found some trout all the way to Pinto,” Cosden said.
Pavol said he would be satisfied if the upper portion of the 18-mile stretch of river between Westernport and Pinto could be kept cool.
“From the fishing guides’ perspective, a shorter stretch of trout water downstream of Westernport that will sustain trout because of measures adopted by the Corps is preferable to our current situation where there’s a question of whether or not we will have any trout downstream of Westernport in some years, followed by a rebuilding process,” Pavol said.
Pavol said he believes the trout population has recovered significantly since “the horror story of 2010.”
Pavol said the river is loaded with aquatic insects. “Caddis flies are thick down there. There is also a fair number of big brown trout. I think most are probably spawned in the Savage River or maybe in the North Branch upstream of the treatment plant,” Pavol said.
Cosden said he suspects there is upstream movement by trout as the river warms. Local anglers report that trout congregate near natural underwater springs during the summer.
Pavol contends that the river below the treatment plant at Westernport, stained because of the effluent there, produces a “perpetual twilight environment” that actually lends itself to more feeding by the trout.
“You can hook a big brown at high noon,” he said. “I don’t think you can do that very often in a clear stream. That makes the river downstream of Westernport unique. Trout grow faster and are more active all day. Makes for better fishing in many ways. We see big browns from Blue Hole to Bloomington, but they rarely hit a fly or lure.”
Contact Outdoor Editor Mike Sawyers at firstname.lastname@example.org.