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Piloting Oyster Reef Structures – Which Will Work Best Where in NY Harbor?

August 28, 2018

Part of what makes oysters such winning ecosystem engineers is their ability to reef together, creating a 3D environment where hundreds of species can thrive. Much like coral reefs, oyster reefs create habitat and can help to protect shorelines from storm damage.

In the muddy bottoms of New York Harbor, oysters need a little help to get the reef process started. Baby oysters cannot survive when sunk in the mud. So, it’s important that baby oysters settle on shells (thank you, restaurant partners!), and that oysters are placed in a way that will allow them to remain close together. That’s where oyster reef structures come in. They provide a stable area for oysters to live together and start growing on one another to create a reef.

Different reef structures have different strengths, and part of our work is to figure out what will work best where in NY Harbor. This process involves designing brand new structures with Harbor School teachers and students, using structures designed by others, and trying out existing structures at new locations and then making adjustments.

On Wednesday, August 15, we installed three types of reef structure never before used at our reefs. We’ll monitor their performance over the next several years.

Learn more about the function of each structure below.

Oyster shells in bags (“bagged shell” in oyster-reef-speak)

What is it?
Standard shellfish bags, filled with juvenile oysters that have attached to (“set on”) on recycled oyster and clam shells in our hatchery.

Why this structure?
Allows rapidly growing oysters to grow through the bag openings and cement together, creating a small oyster reef

Best suited for…
Near the shoreline, in calm waters

Looking forward
To reduce our use of plastic, in 2019 we will begin testing a new bag material made of coconut fiber, which is biodegradable and will breakdown overtime without adding pollutants or microplastics to our water. The only thing remaining will be our oysters.

Fun fact
We are also testing bags of “blank” shells, which means shells have no oyster babies on them. We use bags of “blank” shells in waters nearby to an oyster nursery or another reef, or where there is a wild oyster population, with the hopes that juvenile oysters in the water will find their way to the shells.

ECOncrete disks

What is it?
A new substrate material designed and developed by ECOncrete Inc.

Why this structure?

  • The disk’s design maximizes surface area that free-swimming oyster babies (larvae) can attach to.
  • Disks are cast using a mixture of materials designed to attract accreting species like oysters. Calcium and other additives, which mimic the chemical cues of oyster reefs, have been shown to increase the settlement rate of oyster larvae.
  • Larvae prefer the uneven quality of the surface to flat surfaces.
  • Disks can be stacked into a variety of formations.

Best suited for…
Promotes oyster growth in the subtidal zone


What is it?
A set of metal structures, the original of which was designed by our Executive Director Pete Malinowski, New York Harbor School Ocean Engineering instructor Rick Lee, and Harbor School student Marisol. This latest version was conceptualized by volunteer-welder Lucas Rockwell and then designed, engineered, and welded by Harbor School students interning with Billion Oyster Project, with support from Billion Oyster Project staff and Harbor School Welding Instructor Clarke Dennis. The sliding top is an experimental design that allows the gabions to be loaded with live oysters (vs. loaded with empty shells as is sometimes the case in waters populated with oyster larvae).

Why this structure?

  • Steel gabion structures provide a strong, current-resistant 3D environment.
  • The mesh (galvanized steel) holds the shells in, and outer (raw) steel is for stability and ease of lifting and moving the structures.
  • In the long run, the mesh will degrade over time while the oysters cement together. Eventually the mesh will no longer be needed to maintain the structure of the reef.

Best suited for…
Environments with current; deep waters.


All structures were installed at the Lemon Creek Lagoon Pilot Oyster Reef off of the South Shore of Staten Island. This reef is part of the activities that Billion Oyster Project’s Senior Project Manager Danielle Bissett is spearheading to prepare for the eventual restoration of oysters at the Living Breakwaters Project managed by the Governor’s Office of Storm Recovery (GOSR).

Bags of shells (with oysters and blank) are also installed at our Sunset Park: “Bagged Shell” Pilot Reef Research Project.

Learn more about Billion Oyster Project reefs.

Interested in helping us build oyster reef structures? Explore our volunteer opportunities, and follow @billionoyster on Twitter and Instagram and @billionoysterproject on Facebook.

Interested in reading more about oyster reef structures? Check out Designing Reef Structures for the Hudson River.