In late 2020, New Jersey crews placed nearly 6,000 tons of retired container-inspection concrete forms on the seafloor off Manasquan, adding about 1.25 acres of reef habitat

Somewhere two miles off the Jersey Shore, 151 slabs of concrete that once supported the inspection of shipping containers in Port Elizabeth are now home to black sea bass, tautog and lobster. In late 2020, crews with New Jersey's Bureau of Marine Fisheries dropped nearly 6,000 tons of decommissioned concrete forms, each the size of a small house, 40 feet long, 8 feet wide, and 1.5 feet thick, onto a patch of featureless sand off Manasquan Inlet. According to the New Jersey Department of Environmental Protection, the material, donated by the logistics company Maher Terminals, added about 1.25 acres of new reef habitat to what had been bare seafloor, in a project now called the Maher Terminals Reef. To a generation raised on headlines about ocean dumping and plastic gyres, it's a plot twist: this time, the junk was the point.

From inspection pads to fish condos

The forms weren't made for marine life, but were industrial leftovers, slabs of concrete that had been used to support shipping containers during damage inspections and were set to be demolished and dumped into a landfill anyway. Instead of paying to crush and haul them, Maher Terminals donated them to New Jersey's reef program, which has spent decades dropping ships, rubble, and surplus construction material to make hard surfaces in an ocean that's mostly soft sand for miles along the mid-Atlantic. Hard substrate is a big deal underwater, as barnacles, mussels, and sponges need somewhere solid to latch onto before fish show up to feed and hide among them.

The state says the new structure sits inside the Manasquan Inlet reef site, a 0.84-square-mile zone about two miles from shore. It has now had roughly six years to colonize; plenty of time, based on how quickly New Jersey's other artificial reefs typically develop, for it to have drawn in the recreational anglers and scuba divers the state expected when the material went down, and to have become an established part of the reef network it was designed to join.

It's not a one-off experiment; it is built on decades of federal research. According to a 2012 science review from NOAA's Office of National Marine Sanctuaries, artificial structures can mimic several functions of natural reefs, creating microhabitat for small species, concentrating food resources and providing shelter from currents, and there's broad scientific agreement that they do reliably accumulate fish and other marine organisms. That's the easy part. The harder, more contested question is what happens next.

The debate the press release leaves out

So here's where it gets interesting, and where a skeptical read comes in handy. Marine biologists have debated for decades whether artificial reefs actually grow fish populations or just pull fish in from the natural reefs nearby, concentrating them in a place that's easier to catch. It's called the "attraction versus production" debate, and it isn't settled. In a 2015 study titled “Fish attraction to artificial reefs not always harmful: a simulation study,” published in the journal Ecology and Evolution, researchers modeling fish behavior around artificial reefs found that attraction wasn't inherently bad; it could sometimes spread out fish biomass instead of concentrating it, but the risk of overfishing increases if a high-quality artificial reef was dropped close to an already-thriving natural one. In other words: a new reef can be a genuine ecological win, or it can be just a way to make it easier for anglers to clean out the same fish that were already there. The answer depends largely on the reef's design, placement, and subsequent management, not just on the fact that something got sunk.

Why should this matter

For coastal communities, it's more than just one inlet in New Jersey. Reefs like this one support the recreational fishing and diving economies, and give divers a reason to visit, and repurpose industrial waste that would've otherwise sat in a landfill, a tidy bit of circular economy thinking that fits nicely with how we might think about sustainability. But it's worth resisting the impulse to treat every reef deployment as an unerring environmental good. Sinking concrete isn't the same as restoring an ecosystem, and the science itself suggests the outcome depends on the execution.

The Manasquan project checks a few of those boxes: the donated rather than purpose-manufactured material, the placement within an existing, managed reef network, and the sponsor's commitment to monitoring it annually are all important. It's less about the tonnage. As the research into the attraction-versus-production question already shows, that follow-up question: is this actually growing the ecosystem, or just rearranging it? is one scientists are actively trying to answer. It's worth keeping in mind the next time a headline touts tons' worth of concrete dumped offshore as an unqualified win.