Concrete solutions

Jun 30, 2023

Fishermen are sinking boats and dumping concrete in the Gulf of Mexico — to save the fish

Curtis Haynungs is in his happy place as he's about to set off for the open water on the Gulf of Mexico. The hobby fisherman unties the ropes holding his white, eight-metre-long, twin engine boat to the dock, and eases away as the engines begin to purr.

His family has lived on South Padre Island, Texas, for several generations. The community of 2,000 people, 30 kilometres from the Mexican border, is a laid-back resort town, with sprawling sandy beaches and calm water. It's just as common to see golf carts on the main strip through town as cars and trucks.

But as colourful and vibrant as the island seems, it doesn't compare to what's underwater, said Haynungs, 41, a small business owner, who has been fishing off the coast all his life.

"There's actually prettier colours down there than there is up here. It's an amazing, beautiful world down there," he said on a sunny morning in March.

It's this deep connection to the sea — and his concern for its future — that Haynungs says drove him to help spearhead efforts to build one of the largest artificial reefs in the world, a remarkable feat not only for the reef's size but also for the effort and expense.

So far, local fishermen have built the reef on a section of the seafloor covering about six-and-a-half square kilometres. It's largely made of millions of dollars worth of concrete.

And it's all worth it, he said.

"This material is going to be here for decades and decades to come — that will allow these fish to thrive," Haynungs said.

And while helping sea life has been the main goal of the project, university researchers are also in the midst of a unique study to determine whether the massive man-made reef could also help with climate change.

Haynungs’ deep connection with the water didn't come naturally. Today, he spends much of his spare time with a fishing rod in his hand or scuba-diving among the fish. On occasion, he’ll combine the two and go spearfishing.

But he says his first time fishing with his father, when he was 13, was an unforgettable experience of joy and anguish, thanks to a bout of sea sickness.

"As soon as we left the dock, I was vomiting basically the entire way out," he said.

About 100 kilometres from shore, he hooked a 60-kilogram yellowfin tuna. The fish and his stomach fought him the whole way. An hour passed and he was still throwing up as he tried to bring in the catch.

After three hours, the silver belly, and dark metallic blue, back and bright yellow fins of the tuna emerged from the water. He’d caught the fish, but he was sick the entire journey back to shore. Still, he says he’d found his calling and favourite lifetime hobby.

"The first thing I asked my father is, ‘When are we going to go back?’" Haynungs recalled. "And when I told my father that, he knew I was going to be a fisherman."

Today, his passion is unchanged, but the number of fish in the coastal waters has been decimated.

The Red Snapper population, for instance, rapidly declined beginning in the 1950s and reached its lowest level in 1990. The Atlantic bluefin tuna was declared off-limits in the Gulf in 1982 following decades of overfishing.

Compounding the problem is the damage caused since the 1970s by those catching shrimp, primarily by dragging nets along the seafloor, wiping out coral and flattening the sand and mud left at the bottom.

WATCH | How four anglers came up with the idea to build their own reef:

Around a kitchen table, almost a decade ago, Haynungs and a few friends lamented how bleak the situation had become. For the Red Snapper and other aquatic species to grow in numbers, they needed a helping hand.

The idea of an artificial reef seemed a possible solution as the group came to the realization there was little habitat in the area for fish to grow and breed.

To survive and thrive, the fish need a place to escape from the current, hide from predators and find food.

An artificial reef is a man-made structure to enhance the underwater habitat for reef organisms, like coral, fish and other species that live there. Materials used to construct artificial reefs include rocks, cinder blocks, steel, limestone and concrete.

"So, trying to develop a whole ecosystem here where there was only sand and mud before," said Richard Kline, a marine sciences professor at the University of Texas Rio Grande Valley, who was invited to be a part of the project from the beginning.

Ultimately, Haynungs and some other anglers decided to build their own reef from scratch.

Today, it's called the Rio Grande Valley Reef or RGV Reef, for short. There are tens of thousands of artificial reefs around the world, experts say, but few are as big or as expensive. The RGV Reef is the largest in the Gulf of Mexico.

Texas Parks and Wildlife promotes the development of artificial reefs to grow the number of barnacles, coral, sponges and other invertebrates, especially considering the state has few naturally occurring reefs.

"The Gulf of Mexico is teeming with thousands of species of plants and animals that need hard surfaces to cling to in order to complete their life cycles," the department notes on its website.

Building the manmade RGV reef was a relatively slow process since it took several years just to receive all the necessary permits and to have authorities inspect the concrete and steel. Before sinking a boat, it must be properly cleaned after removing any wiring, fuel, and other materials.

In other parts of the world, mistakes have been made by using rubber tires or other materials that can become loose and cause problems.

Coral reefs are home to about 25 per cent of marine biodiversity, and research suggests half of the world's coral reefs could die off by 2035 due to climate change. Increased carbon dioxide in the atmosphere causes acidification of the oceans, which harms coral and other marine life.

The site off South Padre Island has potential to be replicated in other parts of the world, said Kline, and have a much broader environmental benefit beyond increasing the local fish population.

On that sunny morning in March, Haynungs steered his boat inland about 20 minutes after leaving the dock, through the Brownsville Ship Channel, a deepwater industrial canal that stretches 27 kilometres.

There are oil tanks and a cargo loading terminal visible on one side of the channel, while a former Navy aircraft carrier, Kitty Hawk, is being dismantled piece by piece at a shipbreaking yard on shore. The construction of SpaceX's Starbase in nearby Boca Chica has brought a recent boost of traffic to the port.

Haynungs shut off the motors and the boat slowly glided toward a rigid rock wall on the water's edge. Hopping onto shore, Haynungs walked toward a massive heap of old concrete railway ties, each about a metre long. An excavator uses a grapple to sort the messy pile of concrete into neat rows. It's an onerous process, with more than 15,000 railway ties weighing about 11 million kilograms.

This summer, the Friends of the RGV Reef are planning to have all the concrete dumped into the Gulf of Mexico, adding to the 40 million kilograms of railway ties already on the seafloor.

"These little cracks and crevices," said Haynungs, running his finger along one of the concrete ties. "That allows what's going through the water column to stick to the concrete railway ties, absorbs it, then it starts to grow, whether it's algae or coral."

Concrete is the main building block of the RGV Reef. BNSF Railway, one of the many sponsors providing supplies, equipment or volunteer time to the project, is donating the material. The value of the concrete alone is in the millions of dollars, said Haynungs.

Sometimes, the effects are immediate, said Haynungs, recalling when they purposely sunk a 60-year-old tugboat, so the 28-metre long vessel could become part of the reef. They installed cameras on the boat before it was plunged into the water.

"I must have counted 10,000 fish around that one ship," said Haynungs. "Three days prior, there were no fish around that area."

Kline has been involved in the project since those early days, although his focus has increased in the last year with the launch of a new study investigating the reef's impact on climate change.

"We don't know of another one like it in the world," said Kline. "No one has investigated the carbon-capture ability of a large reef that was just placed on the seafloor where nothing existed before."

Essentially, the research will examine whether the reef acts like a forest, Kline said, and whether the sediments and invertebrates encrusted on the reef can capture carbon dioxide.

In his university lab at nearby Port Isabel, he displays all the gear he uses to examine the reef, from different sonar equipment to an ROV, a remotely operated vehicle similar to an underwater drone that can collect samples and is controlled from a boat.

Using those tools, he's mapped out the entire reef.

"All these little spots on here are actually really big items," he said, as he pointed to a cluster of yellow dots on a red computer screen.

"This is the largest feature in the reef. This is a giant pile of concrete railroad ties that stick up about 32 feet (about ten metres) from the seafloor and it's got about 6,000 tons of railroad ties in it," Kline said.

WATCH | Take a tour of the RGV Reef:

The carbon study is funded from a $250,000 donation from Calgary-based energy giant Enbridge to the Friends of RGV Reef. The company has a natural gas pipeline inland and supports projects in the different communities where it operates in North America.

"It's the perfect example of local communities coming together and figuring out a way to address a local need," said Pete Sheffield, Enbridge's chief sustainability officer, in an interview in Houston.

Determining the amount of carbon in a piece of coral, algae, or barnacle can be a tedious process, taking up to five days for a single sample.

The samples must be weighed and dried out, before being placed in a small furnace heated to 450 F to remove any inorganic material like fish waste, said graduate student Michelle King.

"Reminds me of my childhood easy-bake oven," she said.

WATCH | Counting carbon inside a university lab:

This work is part of a relatively new research field into so-called blue carbon, which was coined over a decade ago to describe carbon captured by the world's oceans and coastal ecosystems.

A year ago, King had no idea that people were throwing concrete into the ocean. Now she's part of the potentially ground-breaking study to understand its relevance to climate change.

"If these artificial reefs can help offset that, it would be amazing to see what we can do in the coming years," she said.

In other parts of the world, scientists have studied different aspects of artificial reefs, such as their ability to attract fish, their impact on other organisms and how they settle on different seabeds.

The RGV Reef study will also act as a large-scale fish count and provide insight into which of the reef structures work best.

There are some early findings.

No matter the type of concrete or steel that sinks to the sea floor, more fish will be attracted to the area, said Kline, describing an "instant return on investment."

Another conclusion, so far, is there is a need for different sizes of reef materials to accommodate the different sizes of fish. For instance, a one-metre high pile of concrete works well for younger fish, while a towering 10-metre stack provides a habitat for older species. Providing some variety helps develop a whole ecosystem.

As for the impact on climate change, the researchers say they have found some evidence that an artificial reef could hold more carbon compared to a natural reef.

Still, the researchers say they are eager for the summer months to arrive, which is ideal for underwater activities, to collect samples and study the reef.

"We just started this project and the amount of sediment down there makes us feel that it can be a substantial amount of carbon that can be held," said Kline, who says he is hopeful this could lead to other artificial reef projects around the world, including in freshwater, such as the Great Lakes.

"We have as humans taken and taken from the environment. Mother Nature is fairly resilient and if we help a little bit, we might get a big return on putting carbon back," he said.

After he finished showing CBC News the concrete pieces that will be sunk into the Gulf of Mexico this summer, Haynungs jumped back into his boat to begin the short return trip to shore.

There is one stop along the way — to see a pair of tugboats, the "Titan" and "Mark K." Both vessels are being cleaned before they, too, will be purposely sent to the bottom of the sea and in the process, continue to build up the size of the reef.

Haynungs said he is immensely proud of what his group has built and what it could mean for the community to bring back an abundance of sea life, especially for the tourism and fishing industries. He sees the revival with his own eyes, as he scuba dives dozens of times every year.

Still, there is much more work ahead. The plan is to keep putting more concrete and steel down into the water for several more years, he said, to grow the reef and the fish population, while sucking up some carbon, too.

"I hope to have kids one day and hope to have them come out to this reef," said Haynungs. "I just want to see them catch fish."

Audience Relations, CBC P.O. Box 500 Station A Toronto, ON Canada, M5W 1E6

Toll-free (Canada only): 1-866-306-4636

TTY/Teletype writer: 1-866-220-6045

It is a priority for CBC to create a website that is accessible to all Canadians including people with visual, hearing, motor and cognitive challenges.

Closed Captioning and Described Video is available for many CBC shows offered on CBC Gem.