Expanding the Jacksonville Oyster Highway: Bioremediation of the New River Watershed

CCA president, Rocky Carter, driving boat to one of the reef sites. (Credit: Jacksonville Media Services Team)

The New River watershed in North Carolina went from a two-decade-long closure of its water resources to hosting a plentiful fishery a few decades later. The change took years of restoration work, and a key part was the installation of millions of small but mighty oysters in the waterway, known as the Oyster Highway project.

In 1980, the city was forced to close the river to all recreational and commercial uses due to high bacterial counts resulting from outputs from the city’s wastewater treatment facility, Camp Lejeune’s wastewater treatment plant, and the air station.

“In 1995, a 20+ million-gallon hog waste spill occurred on the New River and what we found after the spill surprised us. There were no fish kills because the river was already polluted due to wastewater discharges. This is where our leadership and community set into motion a synergy for restoration,” shares Lisa Miller, Communications/Media Manager for the City of Jacksonville, North Carolina.

Stormwater Manager for the city, and lead for the Oyster Highway project, Pat Donovan-Brandenburg recalls the early stages of the restoration project, saying, “All 3 of us shut down our wastewater treatment facilities. The city went 100% to land application, where we are growing a forest and managing that forest (7,000 acres), base went to a tertiary plant, and the air station went to a small land plant.”

Moving live oysters in spat bags from Sturgeon City to boats for the Oyster Highway. (Credit: Jacksonville Media Services Team)

Wilson Bay Initiative

After the closures, the city started the Wilson Bay Initiative, which focused on cleaning up this specific portion of the river using bioremediation. The work was led by 10 million oysters—imported from Virginia and planted in the bay, where none were naturally present.

When the Wilson Bay Initiative began, conditions in the watershed were so poor that the oysters deployed there for bioremediation couldn’t survive on the bottom or through most of the water column.

“We didn’t have any dissolved oxygen on the bottom and so we didn’t have a benthic community, and we didn’t have a real, true finfish community except in the winter months when the DO (dissolved oxygen) went up,” explains Donovan-Brandenburg.

The first set of oysters deployed in the river had to be floated in baskets on the surface, and four in-stream aeration units were installed to transport highly oxygenated water from the deeper portion of the river to the bay and back out.

Over 10 million oysters were used to filter the contaminants in this part of the river, eventually inspiring the Oyster Highway Project in the rest of the watershed.

CCA volunteers, including Pat Donovan-Brandenburg (blue shirt), loading live oysters into the boat. (Credit: Jacksonville Media Services Team)

The Evolution of the Jacksonville Oyster Highway

The river was able to be reopened in 2001 thanks to the Wilson Bay Initiative, though the rest of the river still faced complications. While Wilson Bay had some native bivalves—after adding oysters every year for several years—the rest of the watershed did not.

According to Donovan-Brandenburg, the 50+ years of organics flowing downriver from treated waste covered up all of the hard substrate needed for oysters to settle.

“I wanted to create stepping stone reefs on both sides of the river from Wilson Bay down to Stones Bay close to the inlet that had natural populations,” explains Donovan-Brandenburg.

The Oyster Highway project officially started in 2018 with Phase 1, which included the installation of six reefs, followed by Phase 2 in 2019, which included six more reefs. In 2023-2024, Phase 3 expanded all twelve reefs’ sites from ½ an acre to an acre in size.

Similarly, Phase 4, which is slated for the spring and summer of 2025, will expand the reefs further, adding more oyster castles inside and around the reefs.

David “Clammerhead” Cessna with Sandbar Oyster Company and a UNC graduate student (in the water) releasing oysters onto Artificial Reef 398. (Credit: Jacksonville Media Services Team)

Each of the reefs are made up of multiple oyster structures referred to as oyster castles and oyster catchers. The two structures were selected on the basis of cost, how many oysters could fit into each structure, permitting timelines, and what protected native endangered species most. Other structures may entangle or trap endangered species if they stick their heads in, so the castles and catchers were an ideal solution.

The castles involve a series of interlocking parts that can be stuffed with oysters, so there are no gaps for fish to enter. The catchers are donut-shaped nests that are covered in oysters and are also not capable of trapping any important species in the river.

While Phases 1 and 2 included the installation of both the catchers and castles, the expansion in Phase 3 was exclusively oyster castles because they can fit more adult oysters and are easier to process.

Phase 4 will operate similarly, expanding all twelve reefs by adding substrate in the form of the oyster castles around the perimeter and between existing structures over the next two years, followed by three years of filling these structures.

Oyster castle structure on land. (Credit: Jacksonville Media Services Team)

Donovan-Brandenburg elaborates, “I’ll be putting in two complete rows around the entire perimeter and everything down the middle and the sides with castles this summer. We’ll do six reefs this summer and six reefs next summer, and then I’ll start filling them full of oysters over the next three years.”

While the river has come a long way from conditions in the late 70s and early 80s, the threat of nonpoint source pollution from land runoff continues to impact the watershed.

“You can control the point source pollution, but what you can’t control is what’s coming off of the land,” states Donovan-Brandenburg. “And so even though we’re doing things right, development still has an impact on the watershed. That’s another reason why we went ahead with Phase 4, was to make it bigger and better for decades to come.”

She continues, “My goal was to restore vital marine habitat, improve water quality and continue to improve the overall health of the New River.”

Since the start of the project, an additional 11 million oysters have been placed in the river, playing an important role in filtering out contaminants that can impact the health of the ecosystem today and in the future.

A marine contractor moving oyster catchers loaded with oysters onto a reef site with COJ staff and CCA volunteers unloading. (Credit: Jacksonville Media Services Team)

Evaluating the Success of the Oyster Highway

The success of the Oyster Highway is evaluated through a combination of continuous measurement systems and spot sampling.

“Dr. Joel Fodrie monitors how many finfish are utilizing the reefs, as compared to control sites, quarterly and he has monitored the recruitment, settlement, mortality, and growth of our oysters at all 12 sites quarterly from day one,” credits Donovan-Brandenburg.

The stationary systems include a YSI EXO2 that measures dissolved oxygen, conductivity, salinity, chlorophyll a, turbidity, temperature, and depth, and discrete sampling of the same parameters is done with a YSI ProDSS.

Bacteria counts are conducted every Wednesday, twice a month, from the river directly, and the other two times from the tributaries and high-priority lines. Data from the stationary YSI units are collected every other Tuesday and are maintained on non-collection weeks to prevent data skew. This data is then compiled into a larger historical data set that dates back to 2001.

The team used to conduct benthic sampling trips quarterly up until five years ago, but the river has recovered to a point where these assessments are no longer necessary. The team continues to monitor finfish populations and have noted a 300% increase in the number of finfish that move through the reef areas.

“We see water quality improvements all the time. We have seen recruitment and settlement of new oysters in areas that were completely void before the Oyster Highway,” adds Donovan-Brandenburg.

(Left) Pat Donovan-Brandenburg, stormwater manager, and (right) water quality tech, Maddie Loveless, emptying bags of oysters onto reefs and then transporting bags back to the boat. (Credit: Elliot Bloomberg)

A City Dedicated to Protecting Water Resources

Even with these significant improvements, the city has not grown lenient on its protections of the river or preventative restoration efforts. From the very beginning of the New River restoration efforts, the mayor, council, and city management expressed that they believed cleaning up the river was a moral responsibility.

To this day, operations of the new land application water treatment plants are monitored heavily, ensuring that only treated water is applied and that operations are not impacting the New River.

Private donors like those from the North Carolina Wildlife Habitat Foundation and Eddie Bridges, the Coastal Conservation Association, Rocky Carter, and David Sneed, who have organized volunteers, and public grant funds have helped keep the project running for almost a decade.

“The true success of the Oyster Highway [is] when we see improved water quality, or when we go to collect data and see all the fisherman using the reefs, or see schools of fish and rays in our watershed now, followed by more shore birds feeding, otters and dolphins… and then we find oysters in areas that have not been there in 40+ years,” states Donovan-Brandenburg.

She continues, “[I] never dreamed 7 years ago I would have expanded this far. So yes, we will always strive to improve because you never know what Mother Nature will throw at us next. We have to prepare for the future.”

COJ water quality coordinator Aaron Houran is carrying a row of oyster catchers to a reef. (Credit: Jacksonville Media Services Team)