Oyster shell-recycling programs in Delaware benefit ocean life

By Rachel Sawicki
Posted 10/12/21

When most people think of the term “recycling,” plastic, paper and aluminum are materials that come to mind. But coastal states can add another to the list: oysters.

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Oyster shell-recycling programs in Delaware benefit ocean life


When most people think of the term “recycling,” plastic, paper and aluminum are materials that come to mind. But coastal states can add another to the list: oysters.

Oyster shell-recycling programs across the country collect tens of thousands of bushels of used shells from restaurants, seafood markets and public drop-off locations. Old shells are used in many different kinds of water-restoration projects working to restore oyster reefs that filter the water around them and provide a habitat for fish and other marine life. They also contribute to oyster repopulation.

Sarah Bouboulis, habitats project coordinator at the Partnership for the Delaware Estuary in Wilmington, said larvae will attach to just about anything — including wood, rocks and even garbage — but the best possible surface for them is another oyster shell.

“They are reef-building creatures,” Ms. Bouboulis said. “That’s why we’re using shells because oysters love that the most, and our goal is to create the living structure of an oyster reef.”

Oyster reefs can grow many feet high and many miles wide. All kinds of estuarine animals, such as blue crabs and striped bass, use these reefs as hiding spots, feeding grounds or homes and, therefore, help replenish other marine populations that support local seafood economies.

Once collected, the shells are set out to cure for about a year, letting natural weather patterns, birds and insects chip away at any remaining organic matter on the shells. Ms. Bouboulis said the best time to return the shells to the water is in the spring and summer to catch the fall spawning season and get the most oyster larvae on the shells as possible. Once the larvae attach to the old shells, they are called “spat.”

“(The shells will) get covered in mud or barnacles or other stuff. So you want to put them in the water close to when your oysters are spawning,” she said.

The estuary’s Oyster Shell Recycling Program began in 2016 and collects around 100 bushels per month from restaurants. Ms. Bouboulis said they’ve collected 678 bushels so far in 2021 from seven eateries: The Back Burner in Hockessin; Columbus Inn, Trolley Square Oyster House, Banks’ Seafood Kitchen and Raw Bar, Big Fish Grill Riverfront and George & Sons’ Seafood Market & Oyster House, all in Wilmington; and The Blue Crab Seafood Restaurant & Grill in Newark.

George & Sons’ also has a drop-off bin for people to recycle shells from oysters they’ve eaten at home.

Tyler Esterling is one of the sons of George & Sons’. He said he always encourages customers to return their shells to the shop for recycling.

“It’s for the longevity of the industry,” he said. “It makes more sense to donate them rather than just throw them out. On our side dock, there’s a bucket with some shells where people know to drop them off. … Every night, we make at least four trips out there with 5-gallon buckets full of shells.”

Mr. Esterling said that before they started participating in the recycling program, the market would end up putting oyster shells on the floor of the basement because they had too many.

“It costs more for the dumpster to even pick it up because of all the weight,” he said. “We shuck a lot of oysters here, so it just made more sense to recycle them because it was kind of out of hand with how many shells we had.”

‘Coral reefs of the North’

One of the estuary’s biggest projects involving oyster shells is living shorelines, which connect land and water to stabilize shores, reduce erosion and provide habitats that strengthen coastal resilience.

“I like to say they’re the coral reefs of the North,” Ms. Bouboulis said. “They have so much habitat value. They also help with water acidification. They’ll balance the pH when you use oyster shells, as opposed to other shells or rocks or something like that. So they’re just the best bang for your buck in living shorelines.”

Downstate, the Delaware Center for the Inland Bays in Rehoboth Beach, has several drop-off locations for residents who eat oysters at home. The “Don’t Chuck Your Shucks” program started in 2014. It is similar to that of the estuary’s, with more frequent pickups, since more than 20 restaurants participate. They collect an average of 2,700 bushels of oysters per year and have gathered more than 19,000 bushels since the program started.

The center’s program is also building living shorelines, which help mitigate sea level rise. And living shorelines may be crucial for Delaware’s beach towns.

“Delaware is vulnerable to sea level rise,” said Nivette Perez-Perez, project manager for the Delaware Center for the Inland Bays. “Some of the restoration programs that we do, like living shorelines, are to help to mediate some of the impacts of sea level rise. The projects are a mix of techniques to help flooding events in some of our coastal communities, or stormwater surges or erosion.”

Additionally, the initiative is growing and maintaining three oyster reefs.

“These oyster reefs, all of them are meticulously designed to benefit the areas where they are,” Ms. Perez-Perez said. “Some of the information they’re helping us to develop are finding the areas where we could potentially have natural recruitment of oyster larvae. We already do some monitoring of these reefs, testing how fish and different organisms are already benefiting from these structures.”

One unique aspect of the Center for the Inland Bays’ program is thanks to the plethora of waterfront properties at the Delaware beaches. Residents can become oyster gardeners, caring for juvenile oysters for about a year before returning them to the center to be used in restoration projects.

“We can deliver (spat) as long as the water temperature stays over 50 degrees,” Ms. Perez-Perez said. “But we recruit oyster gardeners year-round. Even if we can’t deliver the shells this year, we’ll put them on our list, and as soon as we have larvae next year, we can deliver the oysters to them.”

According to seatemperature.info, the average temperature is still around 70 degrees. Ms. Perez-Perez added that the oysters in the program are not for consumption but are solely for restoration purposes.

Chesapeake Bay

The Chesapeake and Delaware Canal connects Delaware to the Chesapeake Bay, a huge economic driver for the region. The Chesapeake Bay is home to 348 species of finfish and 173 species of shellfish, many of which have been fished commercially and recreationally for generations. The Chesapeake Bay Foundation has a “Save Oyster Shells” program in Maryland and Virginia, with several participating restaurants and drop-off locations.

Morgan State University’s Patuxent Environmental and Aquatic Research Laboratory in Baltimore completed a study in 2019 examining the potential impact of Chesapeake Bay oyster reef restoration on commercial seafood harvesting. The two-year study found that fully mature oyster reefs in the Chesapeake would yield a 150% increase to blue crab harvests and an estimated $10 million increase in annual fishing revenues in the region.

Allison Colden, senior Maryland fisheries scientist for the Chesapeake Bay Foundation, said there is even a tax credit for shell recyclers. Individuals and businesses can receive $5 per bushel of oyster shells that are recycled, collecting up to $1,500 annually.

“Maryland was one of the first states in the U.S. to implement a shell-recycling tax credit for oyster shells, and that’s because of the recognition of how important oyster shells are for restoration in Maryland in the Chesapeake Bay overall,” Ms. Colden said.

Maryland residents with waterfront properties can also become oyster gardeners. Ms. Colden said CBF recycles about 1,500 oyster shells per year, which is enough to support the entire oyster-gardening program.

“Oyster shells are a hot commodity, and it’s costly,” she said. “As one of our main raw materials that we need for restoration, it really helps our bottom line, as well. If we weren’t recycling the oyster shells, we would be paying upwards of $6 per bushel for that shell from a shelling house. So it also helps our program stretch our dollars a little bit further when people bring that shell back to us.”

CBF does still purchase shells for the rest of the program’s restoration projects. Ms. Colden said they plant 20 million to 30 million spat on shells in a larger-scale program.

Oyster suppliers and restoration programs took a hard hit during the COVID-19 pandemic but found creative solutions.

The Nature Conservancy in Maryland worked with private donors and other partners toward the end of 2020 to purchase more than 5 million surplus farmed oysters from growers in Maine, New Hampshire, Massachusetts, New York, New Jersey, Washington, D.C., and Maryland. All the oysters purchased from Maryland oyster farmers will be placed on sanctuary reefs in the Chesapeake Bay, helping those reefs grow to meet restoration goals.

Although restaurants weren’t able to supply as many used oyster shells as they typically do in 2020, Ms. Bouboulis said her group’s biggest challenge now is finding volunteers.

“Getting the shells into bags is extremely labor-intensive,” she said. “We just have giant piles that we have to get into these bags, and we really rely on volunteers to do that part of it. We also need a lot at a time, like a group of at least 10 people to make it worth it. That was kind of the bigger problem because if you can’t bag it up and move it out of the way, you can’t bring more in, due to our space constraints that we have in our Wilmington location.”

The Partnership for the Delaware Estuary, the Delaware Center for the Inland Bays and the Chesapeake Bay Foundation all have various volunteer opportunities. More information can be found on their websites.