Plight of the Magothy

Originally known as the “Magotty” River, perhaps due to an abundance of mosquito larvae, the now more pleasantly named Magothy River has housing communities lining its shore and is popular with summertime boaters. Like many other tributaries to the Chesapeake, the Magothy’s popularity ultimately has serious consequences for its long-term vitality.

The river has its share of water quality problems based on the big-three water quality indicators: water clarity, dissolved oxygen, and the coverage of beneficial submerged aquatic vegetation known as SAV.  

In 2010, the Magothy’s overall health received a D- grade, a mark that any student intuitively understands and desperately hopes to avoid. This low mark represents a steady decline from the river’s recent high of B- in 2004.  

That year, 2004, was a bit of an anomaly because the population of dark false mussels—a small native bivalve related to the dreaded zebra mussel—exploded in the river and its feeder streams. An estimated 400 million mussels in one stream, Cattail Creek, had the capacity to filter all the creek’s water in a mere 46 hours. Like the oysters that once ranged widely throughout the Chesapeake, these bivalves performed a similar function, improving water quality and especially clarity. But, then they died off.

The filtering capabilities of these animals suggests that some other bivalve, one less prone to cycles of boom and bust, may help restore the river’s water quality. A scientist at the Smithsonian Environmental Research Lab in Edgewater is evaluating the soft-shell clam as a possible oyster wannabe; others have advocated for Rangia, another native clam.

The problem, ”says Dr. Peter Bergstrom, a fisheries biologist with NOAA and a volunteer with the (MRA), is “you want a species that will do well, but that isn’t already doing well.” A bit of a dilemma, and one that hasn’t yet been fully untangled.

Those involved with the MRA haven’t yet given up on the oyster though. In the 1990s, MRA became one of the first organizations to have volunteers raise oysters in cages strung off their docks. Carl Treff heads up the Magothy’s oyster recovery program for the association. He says that 140 Magothy families are now caring for 600 cages housing young oysters. In June, volunteers planted 60,000 oysters on Rock Point reef, one of the most successful oyster reefs in the river.

Last spring and summer’s wet weather is not helping the cause. The wet spring greatly reduced salinity levels in the river; when waters become too fresh, the oysters die off. Then, says Treff, the double whammy of Tropical Storms Lee and  Irene , further devastating the oyster population in the northern bay. All that fresh water led to extremely low levels of salinity throughout the Magothy.

The story of the submerged vegetation is also not a happy one. Despite a few areas of relatively abundant underwater grasses, much of the SAV in the rest of the system has died off, despite the planting efforts of many volunteers.

Bergstrom started monitoring the water quality in the Magothy in 1991 after he and his family moved to the area. The two decades of data provide an ongoing look at the river’s water quality and general state over time. For the last 5 years, the water clarity in the main stem of the river has declined, but scientists are unsure of the cause of this downturn.

Although, the MRA has not yet handed out a grade for the river this year, Bergstrom anticipates, "That it’s pretty much going to be bad again … probably a D-."

Despite the unrelenting bad news, there are a few bright spots. Dissolved oxygen levels in the water have improved a little in 2011. A large number of volunteers still find reason to work on improving the Magothy’s condition. And, more and more watershed stewards—citizens trained to improve the health of their local watersheds—have received certification from the Watershed Stewards Academy.

Both Bergstrom and Treff try to stay positive. To keep their Magothy volunteers motivated, they take their cue from a quote offered by the movie The Inconvenient Truth: “There are a lot of people who go straight from denial to despair without pausing on the intermediate step of actually doing something about the problem.”

Persistence, adds Treff, is key. “We just have to keep the faith; if we do nothing it gets worse. We can do a lot to jump start a reef, and we have to hope that Mother Nature will also help.”

The Magothy River Association will officially announce the yearly grade for the river at its annual meeting in mid February. For more information on the river and how citizens can help, go to the MRA website.