By Rachel Kaufman
It seems totally counterintuitive. After all, the Chesapeake Bay is in a pickle right now because its oyster population, which once filtered impurities from the Bay at a rate of 50 gallons of water per oyster per day. The entire volume of the bay (about 19 trillion gallons) was purified every week. Now, with less than 10 percent of the bay’s original oyster population remaining, it would take a year for the oysters to filter the same water.
So why would eating oysters save them? Aren’t they overfished already?
Yes, but oyster farms are booming.
“Oyster farms can be definite environmental positives,” says Roger Mann, with the Virginia Institute of Marine Science at the College of William & Mary. “Whether they are sitting in the bottom filtering the water or sitting in a cage filtering the water, they’re still filtering the water.”
Simply put, the more oyster aquaculture is done, the more benefits for the waters.
Bruce Wood, owner of Dragon Creek Seafood & Produce in Montross, Va., has seen the effects with his own eyes. When he started his aquaculture operation, in a creek that empties into the Potomac and ultimately the Chesapeake Bay, 10 acres of nearby river were too polluted to use for oyster farming. Not anymore. It helps that he’s using a variety of oyster bred for its tolerance to low salinity waters and disease, which means that even in environments too harsh for wild oysters, his commercially-bred ones can begin filtering the water, improving the environment, and eventually “hopefully reconstitute the native oyster,” Wood said.
Here’s another way eating oysters can help them: Wood’s started a program with one of the restaurants he supplies, Hank’s Oyster Bar in Washington, D.C., where the restaurant will save diners’ shells and send them back to the bay, where they will become the base for new oysters, both cultivated and wild. Without some sort of base, be it shells, stones, or reef balls, similar to what are used to help restore coral reefs, the adult oysters sink into the muddy river bottom and die.
Tossing shells back into the water isn’t a brand new idea, but surprisingly, getting the shells back from restaurants is a relatively recent practice.
The Maryland Department of Natural Resources (DNR) has been re-shelling the bay for decades, getting its shells by dredging elsewhere in the bay. In 2008, though, a sport-fishing group argued that dredging for shells stirred up too much sediment and damaged an important fishing area. So earlier this year, the Maryland DNR piloted its own shell recycling program, picking up 25,000 bushels of shells from two dozen area restaurants.
North Carolina has been running a similar program since 2003, offering a small tax credit for restaurants that participate, but that one’s collected an average of only 14,000 bushels a year.
But the Chesapeake Bay Foundation, which started an oyster shell recycling program in 2007, just two years later announced that it was going to return to focusing on its reef ball program. “The shell is harder and harder to come by,” CBF spokesman Tom Zolper says, “and the reef balls have habitat qualities that are beneficial.” He notes that oysters seem to prefer vertical variety, which reef balls provide and a pile of shells do not, and that the balls, which are made of concrete, deter poachers who would otherwise dredge shellfish from the water.
So is eating oysters a cure-all for the Bay? Maybe not, but it’s more tasty than a ball of cement. So grab your squeeze of lemon and slurp away.
Rachel Kaufman is a writer and editor covering science and the environment, emerging technology, and a potpourri of other topics. Her freelance writing career has taken her inside Victorian-era “castles,” French patisseries, and a haunted train tunnel, and in addition to her work for National Geographic News, her byline has appeared in the Washington Post, ScientificAmerican.com, and CNN/Money. Rachel grew up outside Minneapolis and received her B.A. in English and journalism from Adelphi University on Long Island, but finds her constitution (and temperament) far better agrees with the swampy air of her adopted hometown, Washington D.C. Her blog and portfolio can be found at http://readwriterachel.com and she tweets about science, journalism, and video games at @rkaufman.