In 2016, Texas built RGV Reef from 477 piles of railroad ties and concrete across 1,650 acres off South Padre Island; sonar estimated 24.4 tons of fish biomass there

Somewhere off the coast of South Padre Island, Texas, sits a patch of ocean floor that, as is the nature of the world, flat and muddy. Today, this same section of the Gulf of Mexico supports a wilder environment than ever imagined, with roughly 24.4 tons of fish all concentrated around mounds of abandoned railroad ties and pieces of concrete that people dumped out there.

A 2026 study titled “Comparison of fish biomass and fish carbon content associated with reef sites at the Rio Grande Valley artificial reef in the Gulf of Mexico,” published in PLOS One by University of Texas Rio Grande Valley researchers,

analyzed sonar surveys conducted over the summers and early falls of 2023 and 2024. The RGV Reef, one of the world's largest and longest artificial reefs (1,650 acres across 477 clusters of railroad ties, sunken boats, cinderblock pallets, and concrete pyramids), was found to hold 24.4 tons of fish biomass, or about 2.81 metric tons of pure carbon in living fish. The team estimated the fish population by using a Simrad split-beam sonar to weigh it acoustically, without physically touching a single one.So how did junk turn into a marine ecosystem?


The RGV Reef is an artificial reef, not a natural one. It's an underwater junkyard with a purpose: old railroads, old ships, and concrete barge-pools that were sunk about 10 miles off South Padre Island, with deliberate intent to provide sustenance for fish. However, this is not an off-the-wall concept.

According to a 2024 study titled “Artificial reef footprint in the United States ocean,” published in the journal Nature Sustainability, artificial reefs already cover approximately 19.23 square kilometres of seafloor in the 17 U.S. coastal states that have reefing programmes, and this area has increased by almost 21 times since 1970, primarily in states such as Florida, Texas and the Carolinas. In short, America has been "reefing" for years, quietly. This is just one of the rare, large, and well-documented examples.

The carbon angle

The UTRGV team is not fishing for recreation, and this is the part that will get the attention of a generation enamored with sustainability metrics. With this reef, they are thinking of it as a potential "blue carbon" system: a buried carbon sink in the form of a reef, in the bodies of the snappers, groupers, and all the other fish floating around those railroad ties. The idea is a very interesting approach to ocean conservation; not just to preserve waters that are already clean, but to create new habitats and use it as a carbon reservoir too. It is presented as a climate-minded reuse of old infrastructure rather than landfill waste. Researchers are careful to call this only a "potential" blue carbon system for a reason, though, whether it actually holds up depends on a sperate debate.

The part we ought to keep in mind

Before this turns into an uncomplicated success story, here's some necessary context. There is a long-standing controversy regarding the creation of new fish on artificial reefs, or the aggregation of existing fish from a different location into a convenient, easily harvested area, a debate that is perhaps as old as the idea of artificial reefs, coined the "attraction versus production" debate. Other times, this redistribution effect may actually make fish easier to overharvest than growing the population.

However, according to a 2015 study titled “Fish attraction to artificial reefs not always harmful: a simulation study,” led by researchers James Smith, Michael Lowry, and Iain Suthers, published in Ecology and Evolution, attraction is not necessarily a bad thing and depends highly on how a reef is constructed and fished. In practical terms: a 24.4-ton estimate tells us how much fish biomass is currently sitting on the reef right now; it doesn't by itself tell us whether the reef grew that biomass or simply pulled it in from somewhere else in the Gulf. That distinction matters directly for the carbon story above, too: fish relocated from elsewhere aren't newly captured carbon, they're carbon that was already circulating in the Gulf's ecosystem. It's exactly why the researchers stop short of calling RGV Reef a proven carbon sink and instead frame it as a "potential" one, pending further study of how much of that biomass is genuinely new.

Why this matters beyond Texas

For a generation that has inherited an ocean depleted by overfishing over the past few decades, RGV Reef is a fair example of what can be done with relatively cheap, high-impact environmental remediation: recycling waste materials that many people consider trash. It is not a 'magic bullet,' and the scientists aren't saying it is. However, the "we built this, and it worked, sort of" is more helpful than doing nothing as the Gulf continues to drain.