It's a muggy, humid morning in Bath, North Carolina in late May.
A barge is out in the middle of the Pamlico River near Bath Creek, carrying 100 concrete cubes that will make up a new artificial reef. These cubes are made from 3D printing, the first of their kind in North Carolina.
Two crew members carefully hook the cubes onto a crane one by one, and the crane slowly lowers it into the water.
"We want to have healthy fisheries in North Carolina. Our mission is to help build a sustainable growing fish population for generations," said David Sneed, executive director of the Coastal Conservation Association of North Carolina. "(To start), you have to have a healthy habitat for the fish to grow and reproduce in. That's what these artificial reefs provide."
Artificial reefs are manmade structures that mimic the characteristics of a natural reef. There are approximately 43 ocean artificial reefs and 25 estuarine reefs in North Carolina. State officials strategically place artificial reefs in areas that didn’t previously have reefs. This helps provide refuge for fish and increase fish populations.
The reef cubes deployed in May in the Pamlico Sound were designed specifically to help regionally important species, including striped bass and speckled trout.
The cubes are 3-by-3 feet. There are two rectangular holes on five sides of the cube for fish to swim through. Each cube weighs about 1,800 pounds and is spaced out 10 feet apart underwater.
Using 3D printing for artificial reefs offers unique advantages compared to using traditional materials.
The biggest benefit is that it allows state officials to customize reef structure and size based on the specific needs of the environment.
Until now, the North Carolina Division of Marine Fisheries (NCDMF) has used "materials of opportunity" for artificial reefs. These materials include vessels, train boxcars, precast concrete, or demolition concrete from destroyed bridges or roads.
Natrx, an engineering and architectural company based in Raleigh, created the reef cubes. Natrx focuses on incorporating nature directly into infrastructure solutions.
"(3D printing) has the ability to tailor (reefs) to the habitat. If you have a cast type technique, you really (only) have one product... (But) the ecological and engineering requirements here might be different than in the Neuse River or out on the Outer Banks," explained Leonard Nelson, CEO of Natrx. "With the press of a button, we can change the modules, the structure, the geometry, the roughness to match the features that we need for that habitat."
Another advantage of 3D printing artificial reefs is that it helps to plan projects ahead of time. Jordan Byrum is the artificial reef coordinator at NCDMF.
"These are something that we could... purchase ahead of time... until we have a good spot to put them. These types of materials provide us a little more flexibility with scheduling," said Byrum. "Versus, 'oh we're tearing down this bridge in October. We need to have (the concrete) out of here by November.'"
Natrx has used 3D printing technology before while working on similar projects in other states like Louisiana, but this is the first time Natrx is using 3D printing specifically for a fishery. Nelson said his other projects have been successful.
"Between Hurricane Laura, Hurricane Zeta, Hurricane Ida — a lot of our a lot of our projects have done excellent," Nelson said.
Byrum said depending on how well this project goes, the state agency could consider deploying more 3D printed reefs in the future.
Correction: A previous version of this story incorrectly stated the weight of the reef cubes.
