The Potomac River Fisheries Commission office last Thursday was packed with watermen, residents and conservation agencies who came together to partake in the first-ever Water Quality Information Exchange concerning the tidal Potomac.
Representatives from the Maryland Dept. of Natural Resources and Virginia Dept. of Environmental Quality disclosed recent water quality trends in the river while also fielding questions from the audience.
Margaret McGinty of the Maryland DNR’s Fisheries Habitat and Ecosystem Program said that increases in urbanization near the river have related to lower oxygen concentrations in Potomac tributaries, which translates into a lower fish presence.
“What that means to a fisherman is less opportunity or greater effort if you’re looking to set nets or fish,” said McGinty. “In the higher salinities…we have a lower presence of juveniles and adults of some of the white perch, striped bass.”
While the “fresher” areas of the Potomac with lower salinity didn’t showcase the same oxygen effects that were present downstream, McGinty said that increased urbanization near the freshwater sections has correlated with lower survival of fish larvae and indications of reproduction failure in yellow perch fish.
She added that changes in the landscape are not fuelling plankton and zooplankton blooms that are key food sources for young fish.
“At the larval stage, if they don’t eat well, their survival is going to decline as they grow,” said McGinty.
During the information exchange, one waterman in the audience said he had dredged oysters in the Rappahannock, James and York Rivers and that the shells being used on those waterways for oyster replenishment were clean.
But as for dredging oysters in the Potomac River, he and another waterman said that the shells were covered with some type of slime.
Cathy Wazniak, Environmental Program Manager at Maryland DNR, speculated that it could have been caused by a certain kind of algae or possibly bacteria.
Mark Alling, the water-quality manager for…
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