CAMBRIDGE, MD. — Maryland harvests of native oyster are, by some estimates, now less than 1 percent of what they once were. And the dramatic decline of this pollution-filtering bivalve has changed the entire ecology of the Chesapeake Bay. But scientists say all hope is not lost for the humble oyster.
At the Horn Point Oyster Hatchery in Cambridge, Maryland — part of the University of Maryland’s Center for Environmental Science — a team is dedicated to repopulating the bay with nearly 1 billion oysters every year.
Reversing the effects of overharvesting, disease
Dr. Donald Merritt is the driving force behind the Oyster Hatchery. One of the first things he shows visitors is a video clip of a female oyster expelling eggs.
“So what we’re looking at here is oyster porn,” Merritt explains. That’s right, oyster porn. You can see the video on the WAMU 88.5 Facebook page.
This is how Merritt often talks, which you might expect from a man who’s happy to go by his nickname: Mutt. But there’s a method to Mutt Merritt’s madness: you’re never likely to forget a lesson he’s teaching about his oysters, and he has a lot to teach.
“She’s going to slowly open her shell and pulse a group of eggs out,” he continues. “There she goes. Imagine, an oyster the size of my hand, a very ripe female, could produce tens of millions of eggs.”
Dr. Donald “Mutt” Merritt at the Horn Point Oyster Hatchery in Cambridge, Maryland.
Horn Point’s hatchery was established in 1974 in response to the aftermath of Hurricane Agnes. That storm brought record rainfall to the region, changing the salinity of the Chesapeake Bay. It resulted in catastrophic losses to many species, including oysters.
The hatchery’s main aim was figuring out a way to revive the oyster industry. Initial funding actually came from the Economic Development Administration.
But in recent years the work of Merritt and his team has provided the foundation for oyster restoration efforts in Harris Creek and the Little Choptank River. Both hold sanctuaries where oyster harvesting is now prohibited.
“We believe we’re on pace to restore two of our better oyster tributaries in Maryland in the next five years,” says Mike Naylor, the head of the Maryland Department of Natural Resources Shellfish Fisheries program.
He says pollution, overfishing and the proliferation of two oyster diseases — MSX and dermo — meant that where once Maryland could count on harvesting 15 million bushels a year, the state is now lucky to get a couple hundred thousand.
“The hope is that we’ll allow disease resistance to develop, and for these oyster populations to grow without harvest pressure in these sanctuaries,” he says.
Full restoration, in this case, means something very specific.
In a 2011 report, the Chesapeake Bay Program determined that a successful, sustainable reef has a minimum threshold of 15 oysters per square meter with a total dry weight of 15 grams in that same space, and oysters must cover 30 percent of the reef area.
Can oysters really be “brought back?”
This might seem like we’re getting a bit in the underwater weeds, so to speak, but metrics are important to Mutt Merritt. He’s showing off the giant, gurgling tanks in which Horn Point’s oyster larvae finally set onto carefully cleaned oyster shell.
He says too many people talk about “bringing back” oysters without having a real goal in mind.
“Bringing them back to what? To what they were when John Smith sailed up the Bay? To 1980, to 1990, to 1950? All over the state of Maryland? All over the Chesapeake Bay? There’s all sorts of caveats to that,” Merritt says.
Whatever the target might be, Merritt and his team seem to be getting better and better at raising oysters.
Using eggs and sperm from native oysters, the hatchery has gone from producing 17 million tiny baby oysters, or oyster spat, in 1997, to a record of 1.2 billion oyster spat a few years ago.
One secret weapon Merritt has at his disposal comes in the form of his hatchery manager, Stephanie Alexander, who’s been working with him for 18 years.
“I’ve gone from a one-room hatchery to this huge complex,” Alexander says.
And she does mean huge — the new hatchery (it’s about 10 years old now) has separate rooms for cleaning oyster shells, and developing the algae used to feed the oysters.
There’s also a sophisticated computer program for controlling the temperature of all the water shooting through pipes throughout the facility.
To give you a sense of the scale: one room holds rows of giant fiberglass vats where larval oysters swim around while they’re too small to settle. Each vat holds 10,000 gallons of water. Merritt says the first versions of the vats held just 100 gallons.
But as impressive as the Horn Point hatchery is, it couldn’t operate without people like Alexander pushing herself and nurturing the oysters.
“They’re my babies,” she says. “Every single one of them that leaves here, in some way, I had a hand in producing. I do not eat them — I find them highly disgusting. But they’re good for the bay, and I want to see them out there.”
As for Merritt, beneath his tough exterior, he says he too has a soft spot for the creatures of the bay; he grew up in Maryland, after all. But any optimism he has about bay restoration is tempered by a belief that looking back isn’t always the right move.
“Everybody you talk to wants the bay to be back to what it was in 1960,” Merritt says. “I’d like to have the body I had back in 1960 — ain’t gonna happen.”
But Mutt Merritt will continue to push Horn Point to do better research and hatch more oysters year after year. That way, whatever the future holds for the bay, healthy, disease free oysters can be a part of it.