Relics to Reefs

Why fish can't resist sunken ships, tanks, and subway cars.

This story appears in the February 2011 issue of National Geographic magazine.

It took just over two minutes for the missile-tracking ship General Hoyt S. Vandenberg to sink to the bottom of the ocean. On a clear morning in May 2009, seven miles off Key West, a series of hollow booms erupted from inside the vessel’s hull, where 46 explosive charges had been buried deep below the waterline. The sharp smell of gunpowder drifted on the breeze, and an obscuring veil of black smoke began to rise, but for a long moment the ship didn’t seem to register the shock. She just hung there level in the water, 523 feet long, a rusting, decommissioned hulk with two useless radar dishes that towered above the ocean surface.

Then, as news helicopters circled above and thousands of onlookers watched from boats idling beyond the blast zone, the Vandenberg slowly hitched downward into the Atlantic, remaining perfectly horizontal until finally the bow dropped and the stern rose, leaving nothing but a roiling tract of white water. "There'll be fish living on that wreck this afternoon!" declared Joe Weatherby, the man who had spearheaded the massive project to sink the Vandenberg and turn it, over time, into an artificial reef that would lure divers and fishermen to Key West.

The Vandenberg is certainly not the first ship to be deliberately sunk to create an artificial reef. The waters off the Florida Keys have become the grave site of the Coast Guard cutters Duane and Bibb and the U.S. Navy landing ship Spiegel Grove, and on the sandy bottom 20 or so miles out to sea from Pensacola lies an entire aircraft carrier, the U.S.S. Oriskany—the largest ship in the world intentionally sunk as an artificial reef. Dozens of World War II cargo vessels known as Liberty ships have been submerged, or to use the proper jargon, deployed, all along the Gulf, Atlantic, and Pacific coasts.

People around the world have long known that shipwrecks are prime fishing sites, and since at least the 1830s, American fishermen purposely built artificial reefs out of interlaced logs. In our own time the materials of do-it-yourself reefs have tended to be castaway junk: old refrigerators, shopping carts, ditched cars, out-of-service vending machines. Pretty much anything you can sink has the potential to become an artificial reef. Even officially sanctioned ones are often created from distinctly odd materials, including decommissioned subway cars, vintage battle tanks, armored personnel carriers, oil drilling rigs, and specially designed beehivelike modules called Reef Balls.

The process of how—or whether—a man-made hulk like the Vandenberg becomes an undersea garden is governed by variables such as depth, water temperature, currents, and the composition of the sea bottom. But most artificial reefs attract marine life in more or less predictable stages. First, where the current encounters a vertical structure like the Vandenberg, it can create a plankton-rich upwelling that provides a reliable feeding spot for sardines and minnows, which draw in predators like bluefin tuna and sharks. Next come the creatures seeking protection from the ocean's lethal openness—hole and crevice dwellers like groupers, snapper, squirrelfish, eels, and triggerfish. Opportunistic predators such as jack and barracuda are also quick to take up stations in the water column, waiting for their prey to show themselves. In time—maybe months, maybe years, maybe a decade, depending on the ocean's moods—an alien expanse of raw steel will be encrusted with algae, tunicates, hard and soft corals, and sponges, sprouting life everywhere like a giant Chia Pet.

For decades in the Gulf of Mexico, oil and gas platforms have been prime fishing sites for recreational anglers, since many species of fish seek shelter in their underwater structures. "The economic benefit of artificial reefs is very clear," says Michael Miglini, the captain of a 36-foot charter boat called Orion that takes fishermen and divers out to rigs off Port Aransas, an area blessedly spared from the oil that spilled into the Gulf after the Deepwater Horizon disaster in April 2010. "Creating habitat is akin to creating oases in the desert. An artificial reef is a way of boosting the ocean's capacity to create fish, to increase the life of the Gulf."

Some biologists worry that artificial reefs simply attract fish from natural reefs and may become killing zones for certain sought-after fish, such as red snapper, one of the Gulf's most harvested game fish and presumably one of the species that would gain the most by having new habitat in which to flourish.

"When it comes to red snappers, artificial reefs are bait," says James H. Cowan, Jr., a professor in the Department of Oceanography and Coastal Sciences at Louisiana State University. "If success is judged solely by an increase in harvest, then artificial reefs are pretty successful. But if those structures, which are usually deployed in shallow waters to make them more accessible to fishing, are pulling fish off natural reefs farther from the coast, they may actually be increasing the overfishing of species that are already under stress."

Some artificial reefs have become hazards to navigation and a toxic insult to the waters in which they came to rest, steadily leaking contaminants for years. The danger of pollution is the reason almost 70 percent of the Vandenberg's $8.4-million sinking budget went to cleanup efforts, including the removal of more than ten tons of asbestos and more than 800,000 feet of electrical wire. And for every foot of wire there was a foot of red tape, since artificial reefs must now be created in strict accordance with the U.S. government's National Artificial Reef Plan.

Even scrupulously planned deployments can go very wrong. When the Spiegel Grove went down prematurely off Key Largo in 2002, she landed upside down with one corner of her stern on the bottom and part of her bow above the waterline, ready to serve as a can opener to unsuspecting vessels plying the marine sanctuary. It took a massive salvage effort to get her over on her side and fully underwater, and it wasn't until three years later that Hurricane Dennis finally gave her the intended upright profile.

Despite her problems, the Spiegel Grove ended up a success story, unlike the notorious Osborne Tire Reef off Florida's Broward County. This project was initially thought to be a good idea in the early '70s, a win-win environmental stroke that would liberate the nation's landfills of up to two million discarded tires to create a thriving marine habitat.

But it turned out that vulcanized rubber is actually a poor substrate for coral growth, and the bundled tires, instead of helping to augment two adjacent natural reefs, ended up smothering and bashing into their fragile organisms. When the bundles broke apart, the tires washed up on the beaches. The hopeful Osborne Tire Reef initiative has now given way to its expensive remedy, the Osborne Reef Waste Tire Removal Project.

Artificial reefs aren't just the final resting places of tires and ships. Several companies have arisen to serve people who have the desire to become artificial reefs themselves, but reef burials are still a microscopic niche market of the funeral industry. Jim Hutslar, one of three partners behind Neptune Memorial Reef, invited me to accompany him one spring morning on a maintenance run to the underwater cemetery he's constructed in 40 feet of water four and a half miles off Miami Beach. As Hutslar used his dive knife to scrape algae off memorial plaques, I swam down to inspect the first phase of what will eventually be a 16-acre underwater memorial garden.

The water was murky, which only added to the mood of unworldly discovery this bizarre apparition is clearly meant to impart. What I saw was a grouping of broken columns, with colonnades branching off on either side, and two massive bronze lions guarding a sagging iron gate.

Neptune Reef was originally conceived as an art project, a hidden-away artifact from our romantic cultural memory that would molder away by picturesque degrees at the bottom of the ocean. Burials became a way of financing the project, and so far there have been about 200 "placements."

People laid to rest in Neptune Reef are cremated, their ashes mixed with cement and either encased in the columns or molded into sea-star, brain-coral, or other shapes. I swam among sergeant majors, grunts, parrotfish, and French angelfish as I paid my respects to the submerged. The people laid to rest here must have been familiar enough with the processes of the ocean to know that these placements would soon be engulfed by invertebrate life, that damselfish would one day be laying eggs and cultivating patches of algae on their bones, so to speak.

I hovered in front of one of the big lions. Poised on its towering pedestal, it was more than 15 feet tall, and my view of it was periodically obscured by sidling schools of fish. The lion had been there only six years but already seemed like something secreted away for many human ages, red algae growing between its claws, colonizing corals spreading through its mane. It should have been cheesy, but somehow it was not. Instead, it seemed a testament to the marvelous power of the ocean to claim almost every sort of material—including the human body—and make it flower with life.