Oysters planted on bar in Choptank River
CAMBRIDGE — A hand tonging bar in the Choptank River was planted with more than 10 million baby oysters, or spat, on Tuesday, July 19.
The planting, while still part of the state’s plan for oysters, is different in that the oysters were planted on a public bar, rather than in sanctuaries where watermen can’t harvest.
It’s part of a program where county watermen associations and the Department of Natural Resources partner to plant hatcheryraised oyster spat on public bars.
DNR Secretary Mark Belton said watermen are charged $1 for every bushel of oysters they har vest. That money is allocated to a special fund, which is spent on activities like the Dickerson oyster planting on Tuesday that are specifically requested by county oyster committees.
“If you harvest an area, you’ve got to put shell back at some point for the spat to adhere to and grow for the oysters in the future,” Belton said.
Belton, along with University of Maryland Center for Environmental Science Horn Point Laboratory Director Donald “Mutt” Merritt, and Oyster Recovery Partnership members got aboard Dorchester waterman Ben Parks’ boat on Tuesday and sailed out to Dickerson oyster bar, known colloquially as Turtleback, in the Choptank River.
There they met with ORP boat Robert Lee, which carried a mound of oyster shells and power hosed them from the boat’s deck
into the water overtop Dickerson bar.
Parks, who is also on the state’s Oyster Advisory Commission, verified the planting. The spot was chosen by the Dorchester County Watermen’s Association, and the planting was facilitated through ORP, which provided the shells from its shell recycling program, and the Horn Point Laboratory, which grew the spat and placed the oysters on the shells.
The bar has been receiving hatchery oysters for the past several years, Parks said. Watermen will be able to legally harvest the oysters planted Tuesday once they grow to market size in about three years.
Oyster are revered in the Chesapeake Bay for their ability to filter potentially harmful nutrients out of the water. But what’s more important is the filter feeder community that colonizes oyster bars, of which the oysters themselves are the building blocks, Merritt said.
“We can take you up to a place up in front of the (Cambridge) Hyatt where every oyster is just wrapped up with mussels,” Merritt said. “Those mussels also filter, so it’s not just the filtering capacity of the oysters, it’s the filtering capacity of the reef community that wouldn’t be there if it wasn’t for the oysters.”
Planting the oysters not only provides ecological benefits to the Dickerson bar, but it also puts oysters there for watermen to eventually harvest, once the oysters reach at least 3 inches in size.
Parks said watermen used to plant Dickerson bar with wild seed, but added that if it wasn’t for the hatchery seed, the oysters would reproduce “at a rate so small it’s not economical for the watermen to harvest there.”
Merritt said the wild seed wasn’t of the same quality as the hatchery seed.
“There weren’t as many spat per bushel in the wild seed. You would move stuff up here that’s got 100 to 500 spat per bushel on it,” he said. “This stuff (hatchery oysters) has probably got 3,000 spat per bushel on it, so you could put shell over in the hopes that you’ve got a strike on them. They didn’t always catch, so if you put that shell over and you did get a strike, you’ve got nothing to move.”
Merritt said Horn Point checks each tank, in which it raises oyster larvae and where they catch to the shell, before the oysters are deployed for planting. If there’s not enough spat, more larvae can be added, “so we’re taking a lot of the guess work out of oyster restoration in that, and it works,” he said.
Dickerson bar is only open to hand tonging. If more efficient gear is used there, like patent tongs or dredging, the oysters on that bar would be gone in about two weeks during oyster season, Parks said.
Only allowing hand tongs there allows watermen to work through most of the winter, and the same goes with areas of Broad Creek, another public fishery area, and a place called River bar outside Tilghman Island, he said.
Merritt called the Bay’s oyster population “recruitmentlimited” and “broodstock-limited,” meaning reproduction levels are dependent on the oyster population already there.
“There is no site that I’m aware of ... that has the intensity of spat fall and the regularity of spat fall conducive to have a growing oyster population,” he said. “Back in the 1960s, you had places that would consistently give you 1,000 or more spat per bushel. In the last 20 years, you’ll be lucky to find a place that’s got 100 spat per bushel.”
Asked why spat recruitment has declined, Merritt said it’s a hard question to answer.
He pointed to anoxic water — areas with no oxygen that oysters need to survive — and shell buried under mud that used to be on top of the bottom’s surface as being part of the problem.
But he pointed back to there not being enough broodstock, or reproduction-age oysters, as why spat recruitment, overall, has declined.
“If you believe what some scientists have said ... we are now, our oyster populations, are at 1 percent of historic levels,” he said. “If everything else being equal, you should see one percent of their recruitment, because you took 99 out of 100 parents away. I think that’s a big part of it.”
“Which is why the sanctuary program can be so important. It can provide that broodstock ... those oysters can spawn before they’re big enough to be legally harvested,” he said.
The DNR is working on a five-year report for its sanctuary program, and it’s due out this July.
Talbot County watermen in December 2015 successfully protested remaining sanctuary construction being done by the U.S. Army Corps of Engineers in the Tred Avon River. They claimed that a completed sanctuary, Harris Creek, wasn’t providing any more oyster spat recruitment than its neighboring public fishery creek, Broad Creek, despite the 2 billion oysters planted there.
The watermen wanted to delay sanctuary contruction in the Tred Avon River until the five-year oyster sanctuary report is released and a conclusion with all the data can be made on how to move forward with Maryland oyster restoration.
The Tred Avon River part of that report has been given to the state’s Oyster Advisory Commission, which is scheduled to meet on July 25 and come to a consensus on how to move forward with the Tred Avon River.
The Choptank River Lighthouse glows beneath the blue evening summer sky as the July sun sets along the waterfront at Long Wharf Park in Cambridge.
Oysters are hosed off the Robert Lee, a boat owned by the Oyster Recovery Partnership, onto Dickerson oyster bar in the Choptank River on Tuesday, July 19.
The Robert Lee, a boat owned by the Oyster Recovery Partnership, begins to dump 10 million oyster spat on Dickerson oyster bar, in the Choptank River, on Tuesday, July 19. Dorchester County Watermen’s Association specifically chose Dickerson bar, a hand tonging area, for the planting.