Stephanie Alexander at the Horn Point Lab oyster hatchery. Lawn chemicals pollute Chesapeake Bay. Oysters fight back.
Today I want to expand on my 2019 blog post about New York City’s Billion Oyster Project, which uses restaurants’ discarded oyster shells to fight erosion in the harbor.
According to a July broadcast of Living on Earth [LOE], Pittsburgh restaurants are doing something similar. In this case, it’s to counteract pollution caused by fertilizer that runs into Maryland’s Chesapeake Bay.
LOE’S BOBBY “BASCOMB: The Chesapeake Bay is routinely inundated with fertilizer runoff from the surrounding watershed in parts of Pennsylvania and Maryland. The result is algae blooms that suck up oxygen in the water and create dead zones for most other forms of life in the Bay. Oysters are particularly vulnerable, but as Kara Holsopple of the Allegheny Front reports, some local groups have come up with a novel way to help oysters recover.
“KARA HOLSOPPLE: Jessica Lewis says shucking an oyster is like picking a lock.
“JESSICA LEWIS: You press down and then you just wiggle, pop it open and, the abductor muscle right there. You clean that. …
“HOLSOPPLE: Lewis says they go through about three to four hundred oysters here a week from the East and West coasts. This oyster is from Maryland’s Chesapeake Bay — and its top and bottom shell are going back there… Lewis and her staff toss the spent shells in a 35 gallon barrel with a screw-on lid, located in the trash area on the ground floor of the building. …
“About once a month a truck picks up the old shells from this and six other participating restaurants in Pittsburgh, and drives them more than 250 miles to a staging area just across the Chesapeake Bay Bridge in Maryland. From there, the oyster shells from Pittsburgh and ones collected from Maryland, Virginia and the D.C. area are taken to a site at the University of Maryland’s Horn Point Laboratory in Cambridge, for processing.
“KARIS KING: So here you’re looking at about 7,000 tons of clean shell.
“HOLSOPPLE: Karis King is with Oyster Recovery Partnership, a nonprofit which works to increase oyster numbers in the Chesapeake Bay. We’re standing at the base of a mountain of gray shells. They’ve been dumped into a machine that’s like a modified potato hopper, which sorts the shells. … Smaller fragments of broken shell fall away as a conveyor belt deposits the half shells into wire cages or piles where they’re cured for a year. …
“KING: Even with all the shell that we do recycle, and that we also purchase from shucking houses, we still don’t have enough to do large scale restoration, at the rate that we could.
“HOLSOPPLE: That’s because of the scale of the problem. Stephanie Alexander manages the Horn Point Lab oyster hatchery. …
“ALEXANDER: We’ve pretty much wiped the oyster out to less than 1 percent of historic levels. So we started this restoration effort where we’re using a hatchery to produce spat on shell to put back into the bay so we can kind of help jump start Mother Nature.
“HOLSOPPLE: The concept is pretty simple: Scientists here at the lab produce baby oysters from adults harvested from the bay, nurture the microscopic larvae with a custom algae diet, then get them attach to the recycled, treated oyster shells. That’s the ‘spat on shell.’ In practice, it’s a lot harder than it sounds…
“Ben Malmgren is an intern here, a student from St. Mary’s College of Maryland.
“BEN MALMGREN: Right now we’re placing the oysters out on the spawning table where we are going to simulate river conditions that are ideal for spawning.
“HOLSOPPLE: The saltiness and temperature of the water in the shallow black basins has to be just right. Malmgren places the oysters in a grid formation, so it’s easier to separate the males from the females…
“MALMGREN: Because if we just let them spawn out on the table all these eggs are gonna go down to the into the drain. So once we see a female and we’ll we’ll know she’s a female by she’ll clap her top and bottom shell together and we’ll see a plume of eggs come out. …
“HOLSOPPLE: Even in the lab, nature is in charge. Stephanie Alexander says it was a slow summer…a lot of rain meant the adult oysters have lived with lower salinity levels, and they’re stressed. Out in the bay, the water is warmer, meaning the spat on shell might have a harder time growing that second shell, and over the years, forming the clusters that create oyster reefs.
“STEPHANIE ALEXANDER: When one thing gets out of whack everything else is going to kind of follow. So we’re trying to get the oysters back into balance so then hopefully everything else will follow as well. …
“Oysters are the vacuum cleaners or the kidneys of the bay and they just suck the water in, they decide if it’s food or not food. But no matter what it is that will remove it from the water column and that’s how they vacuum the bay up and clean it.
“HOLSOPPLE: Because of this superpower, oyster aquaculture is a best management practice identified by the regional partnership that oversees cleaning up the Chesapeake Bay. Some of the spat raised at the Horn Point Lab will make its way to oyster farmers, and those are the oysters on a half shell that are served in restaurants. But the majority of the spat will help rebuild oyster reefs, creating habitat for fish, and restoring the ecosystem.”
More at Living on Earth, here.
Suzanne's Mom's Blog 
Recycling oyster shells is a good one. I never thought about it. Thank you 😊
I like to revisit topics. New folks, like you, would not have seen the earlier post about recycling oysters in New York.
Yes. That’s true. Thank you 😊
A lovely example of humans trying to re-connect a much-needed feedback loop in these ecosystems…
In the past, we were unkind to oysters — as bad as the Walrus and the Carpenter, who invited oysters for a walk and talk and when, after a while the conversation became one-sided, realized “they’d eaten every one.”