This man-made material could help save NC’s oyster population

A scientist and oysterman come together to help save NC's declining oysters with a biodegradable material.

MOREHEAD CITY — His friends and neighbors know him as "Clammerhead." David Cessna has spent a lifetime cultivating and harvesting oysters along North Carolina's coast. His partner, UNC-Chapel Hill marine biologist Niels Lindquist has spent his career studying marine organisms. Together, they’re trying to revive the oyster industry in North Carolina.  

“Oysters have underpinned coastal economies for centuries, if not longer,” says Lindquist.  

“We've had unfortunately some pretty severe crashes in oyster populations and in some places around the world, oysters are functionally extinct.” 

Lindquist explains that sea level rise, encroaching salt water from dredged inlets and changes in how fresh water flows into the estuaries all threaten oyster populations.  

“In North Carolina, we're probably at about 10 percent historical abundance,” he says.  

“It's not the same world that it was 100 years ago.” 

So when a North Carolina Sea Grant initiative paired Clammerhead and Lindquist together, they started working on new approaches to reestablishing North Carolina's oyster population. Habitat loss is one of the main reasons for oyster declines, so the two decided to manufacture new oyster habitats.  

“We came up with an idea for a new material to grow oysters on that we call oyster catcher,” says Lindquist. “When Clammerhead and I were thinking about materials, the idea of plant fiber, clothes-like burlap or jute came up.” 

They mixed cloth with cement in an Igloo cooler and realized they had something. They soak the burlap cloth in cement and form it into different shapes. The cement gets in between the fibers and provides structural integrity.  

And then through time hopefully these oysters will settle out onto the cement and then the fibers will break down and we'll be left with just the oyster,” said Lindquist. 

The material is biodegradable, and once the oysters clump together, they can create a self-sustaining reef.   

The first shape to emerge was the rasta. Rastas look like dreadlocks. But these fiber and cement creations can be used in almost limitless applications. 

“We needed something that didn't weigh too much, could be handled relatively easy and could be put together in modular pieces,” said Clammerhead.  

“The shape that we've created here is one that you often find with a natural reef growing along a shoreline. The oyster reef will start to grow out and at the point of the reef, the flow is the highest and that's where the best oyster growth is.” 

Clammerhead said they’re already seeing oyster communities populate the rastas after a year. In addition to providing more oyster habitat, the rastas can also protect the shoreline from erosion.  

“We have an opportunity to work in multiple different markets including oyster aquaculture, but also in habitat restoration and shoreline protection,” said Clammerhead. 

The team also designs what they call “cow patties.”  

The patties are used to nurture infant oysters that can easily be relocated to create new oyster populations. Colors added to the patties can even be used to identify individual oyster growers. 

“And so when we're growing a seed oyster for aquaculture and getting single oysters off of this, they'll carry a little piece of this cement embedded in their shell,” said Lindquist. “So by coloring it, we can basically brand our oysters so we know where these oysters came from.” 

Perhaps most importantly oyster catchers will leave no trace. 

“If you're successful with it, the reef will grow on its own. But if you've made a mistake, our material will degrade and disappear over time so you don't leave a legacy,” said Linquist. 

“I can see a difference that we're making in the environment, what we can do for coastal areas, what we can do for the state economy and what the sub-straight can do just for environmental problems that for a long time have been hard to address.”