Can the bay be healed?

While the oyster revival is still in its early stages in Maryland, it stands to restore much more than just the state’s maritime economy. Oysters could also play a significant role in reviving the complex ecosystem of the Chesapeake Bay.

The largest estuarine system in the country, the Chesapeake spans some 200 miles from Havre de Grace, Md., to Virginia Beach, Va. The gnarled, intricate branches of more than 100,000 rivers, streams, and creeks intertwine across its 64,000-square-mile watershed, which stretches across six states. The miles of shoreline of the Chesapeake and its tidal tributaries alone are more than the entire West Coast put together.

But the bay is in rough shape – and not just because it has been hammered so hard by a history of overfishing. Wastewater treatment plants and air pollution release dead-zone-contributing nutrients into the Chesapeake. Stormwater runoff from cities and streets is such a major source of pollution that state officials warn against swimming in the Chesapeake’s waterways for 48 hours after heavy rainfall. And more than 87,000 farm operations – the kind that involve working the land, not the water – now dot the Chesapeake Bay watershed.

Wikimedia map of the Chesapeake Bay

Chickens are a particular problem. Across Maryland’s Eastern Shore, the birds outnumber people 1,000 to one, thanks to factory farming conglomerates like Perdue, based in the city of Salisbury. Md. In 2008 alone, the chicken farms of the Delmarva Peninsula generated 1.5 billion pounds of shit – that’s more than every human living in New York, Washington, D.C., San Francisco, and Atlanta put together. Their manure introduces tons of nitrogen and phosphorous into the waters of the Chesapeake every year, causing harmful algae blooms that deplete the bay of oxygen and create massive “dead zones” each summer.

More oysters could certainly help aid this immense problem. Remember: The mighty bivalves are ocean filters. Oysters soak up nitrogen through their flesh, turning the nutrient into a benign gas. They absorb nitrogen into their shells, too, and can store it there for decades, or even centuries, long after the little creature inside its shell is dead. At their most plentiful, the Chesapeake’s oysters were capable of filtering all 18 trillion tons of bay water in about a week, rendering it nearly crystal clear.

But it’s a lot harder out there for an oyster than it used to be.

Efforts to revive the Chesapeake Bay have been endless, dating back to the mid-’70s, when the estuary became the first in the country targeted by Congress for protection and restoration. Though the EPA has an office dedicated specifically to the Chesapeake, a target set in 1987 to reduce nitrogen and phosphorus entering the bay by 40 percent by 2000 was largely unsuccessful. By 2009, it was clear that another goal, to have the Chesapeake removed from the Clean Water Act’s “dirty waters” list by 2010, would also be a failure. President Obama stepped in to hasten the work, with an executive order detailing a federal restoration strategy for the watershed. The following spring, the EPA put the bay on a strict “pollution diet” that set maximum nitrogen, phosphorus, and sediment levels that flow into the Bay each day.

Three years after the landmark pollution diet was established, sediment loads in the bay were still 24 million pounds behind restoration goals, but watershed states are more than 5 million pounds ahead of schedule for nitrogen removal and more than 1 million pounds ahead for phosphorous. But farmers and developers sued to overturn the cleanup effort, claiming the EPA had overstepped its legal authority, and that cleanup should be left to the local governments of the bay’s watershed. Last year, 21 states joined a lawsuit brought by the American Farm Bureau Federation to rebuke the pollution diet and release farmers from tightened water pollution controls.

And while there were signs that O'Malley's oyster restoration plan was having a positive effect on the fishery, his successor, Republican Gov. Larry Hogan, wasted no time in reversing some of the hard-won progress. Before leaving office late last year, O’Malley proposed regulations to reduce phosphorus, calling for farms near bodies of water to either drastically reduce or stop using manure. Gov. Larry Hogan, a Republican who promised during the election to repeal storm-water management fees, nixed the phosphorus regs immediately upon taking office in January. A month later, he proposed his own set of regulations, which are more friendly to farmers, though farms with phosphorus usage above a state-determined level would be banned immediately from using any more on their crops.

With or without pollution controls, oysters aren’t an environmental cure-all. “It’s not the silver bullet,” Luckenbach says. After all, it’s one thing for aquaculturists to grow a few million oysters; it’s another thing to restore the billions upon billions of bivalves that once lived in these waters.

Some of the ecological good oysters provide can actually be reversed if they are farmed at too large a scale, Luckenbach says. Though it has yet to occur on large-scale oyster farms, too many oysters in one farm can deliver an excess of organics to the Bay bottom, he says, rendering it anoxic, or devoid of oxygen, and not very life-sustaining. The phenomenon has been observed widely in large-scale mussel farming.

Nonetheless, plentiful reefs are elemental to a healthy Chesapeake. A robust aquaculture industry, combined with healthier wild stocks, could have dramatic effects on the ecosystem.

Take the Potomac River, for example – the largest of the Chesapeake’s nine major tributaries and the fourth largest river on the Atlantic coast. The Potomac’s watershed boasts the highest human population in the region, spanning West Virginia, Maryland, Virginia, and Washington, D.C. It is responsible for 28 percent of all the nitrogen that flows into the bay. According to a study by NOAA and the U.S. Geological Survey, if aquaculture and restoration transformed 40 percent of the river bottom into well-stocked oyster reef, all of the nitrogen in the Potomac could be removed.

That kind of number gives conservationists, watermen, and lovers of wild places hope that the bay could some day become an example of how humans are able to revive a devastated ecosystem.

PHOTO BELOW BY DAVID HARP