A freak tourist attraction lures scuba divers to a spot off Fort Lauderdale: an undersea graveyard of discarded tires, more than half a million of them, stretching across the ocean floor. In the deep violet light at 70 feet, the sight is shocking: steel-belted radials covering an area the size of 27 football fields.
The tires were dropped into the water in the 1970s in an attempt to create an artificial reef to attract fish, which in turn would attract fishermen. But the plan failed. The bundles of tires broke up, ruining part of an actual coral reef and attracting few fish. Left behind was a barren waste dump of tires that environmental agencies are still trying to clean up.
No one is building tire reefs anymore. But state and local governments in the Gulf of Mexico are receiving billions of dollars in compensation money from the BP Deepwater Horizon oil spill over 15 years to restore habitats and compensate for economic and recreational losses. Some states, such as Texas and Florida, are using several million of these dollars — at least $45 million — to build a different kind of artificial reef, made of concrete pyramids, tubes, and boulders. Compared with the failed tire reef, the materials are better, and the placement more secure. The completed artificial reefs will join thousands of others in the gulf that successfully attract red snapper and other sought-after species, making them hugely popular with the fishing community.
They may be a hit with fish and fisherman alike, but many scientists consider artificial fishing reefs to be blots on the marine environment — glorified fishing gear that lures fish to waiting hooks. Scientists also worry about their tendency to attract non-native species, such as the orange cup coral, which kills and outcompetes native corals. And some scientists say that by changing soft bottom to hard bottom, these artificial habitats have opened the way to the arrival of ciguatera, a toxin whose microscopic host requires firm surfaces to survive and was rarely before found in the gulf. Ciguatera sickens people who eat infected fish.
The impact of artificial reefs remains a topic of intense research and debate, with supporters saying that they actually increase a region's carrying capacity by producing more fish, not just attracting them. But there is something bizarre about responding to one of the worst environmental disasters in history with further attempts to manipulate the marine environment.
"Usually these structures are much more about attracting fish than they are about helping fish survive," said John McManus, director of the National Center for Coral Reef Research at the University of Miami, who can't even stand the term reef for such contrived entities. "It's not generally a good idea to add to overfishing by putting in fish-attracting devices. They just keep sucking more and more fish out of the environment."
Texas plans to deploy 2,400 concrete pyramids, each 8 feet tall and 10 feet wide, at two spots southwest of Houston. A similar project is planned off the coast of Alabama. Mississippi plans to cover 100 acres with limestone rubble, another type of artificial reef structure. Off southwest Florida, local governments are using BP money to help build what they claim will be the largest artificial reef in the Western Hemisphere, a quarter-mile on each side, constructed from 18,000 tons of concrete rubble, light poles, and pipes.
Charter captains, like Bob Zales, whose fishing boat Leo Too sails from Panama City Beach, love them. Zales said artificial reefs — ranging from the accidental reefs created by oil platforms to private and public reefs installed in coastal waters — become encrusted with corals, sponges, and other organisms. That attracts new species of fish, which have made marine life in the gulf more abundant.
"They created a whole new habitat," said Zales, who has fished the gulf for 51 years and knows scientists who both oppose and support the concept. "There's coral in the gulf that didn't exist before, there's species of fish that hadn't been there before. You didn't used to have jewfish — well now they call them goliath grouper — and jewfish are everywhere. Amberjack didn't used to be a species caught off Louisiana in the abundance that they do, until they put the oil rigs out there. Before they had rigs, they didn't have red snapper off Louisiana or off Texas."
Artificial reefs predate even the oil rigs — they go back to the 17th century, when the Japanese learned they could attract fish by placing piles of rocks and structures of bamboo in the water near shore. In South Carolina in the 1830s, residents built them out of logs.
And then, thanks to the 20th-century boom in consumer goods, all sort of junk was placed into the ocean: old washing machines, refrigerators, toilet bowls, subway cars, airplanes, ships, shopping carts. The aircraft carrier Oriskany was sunk as a reef off the Florida Panhandle, becoming known, inevitably, as the Great Carrier Reef. There's even a company called Eternal Reefs that will mix your cremated remains with concrete to make a coral-supporting reef ball for placement on the ocean floor.
Plus, when a ship smashes into a coral reef in the Florida Keys, the owner is required to pay for the placement of concrete boulders or some other structure to replace the coral substrate that was lost — a practice widely regarded as an acceptable reparation. With time, corals, sponges and other marine life encrust the concrete, and it becomes indistinguishable from the natural reefs.
But that doesn't mean artificial reefs are natural. James Cowan, a professor in the Department of Oceanography and Coastal Sciences at Louisiana State University, has spent years studying artificial reefs, and he believes they alter fish behavior in a manner that harms fish. Red snapper do flock to artificial reefs, but having found a safe home in a rough neighborhood (i.e., the rest of the ocean), the fish are reluctant to venture out for food. They end up weighing less than their counterparts that are pursuing a more dangerous, but otherwise healthier, life in the natural world. "What we've learned is that by no measure of condition are the fish on the artificial habitat as healthy as fish on the natural habitats," he said.
This lack of adequate nutrition prevents female fish on artificial reefs from reproducing, Cowan said. They start preparing their eggs for release and then reabsorb them as a survival mechanism because they can't afford to lose the nutrition that went into their eggs. So the fish may survive, but they don't produce eggs. Plus, it seems fishermen can't resist them, said William Lindberg, associate professor of marine behavioral ecology at the University of Florida.
Consider this experiment: For a study of gag grouper, Lindberg and his colleagues set up secret artificial reefs in the gulf about 70 miles north of Tampa. They studied the fish that showed up. Then they released the reefs' locations to the public. Within eight months, every legal-size gag grouper was gone.
"Large reefs promoted for public fishing will attract gag seeking refuge from natural mortality but will expose them to intense fishing mortality," he wrote in a report to the Florida Department of Environmental Protection. "In effect, intense fishing can de-couple the shelter-seeking behavior from its presumed adaptive advantage, i.e., avoiding predation. When used in that manner, artificial reefs function as sink habitats and, in our view, are more properly considered fishing gear rather than habitat enhancements."
Among the biggest scientist backers of artificial reefs is Bob Shipp, an avid fisherman and fishing tournament judge who recently retired as chairman of the Department of Marine Sciences at the University of South Alabama. While he agrees that individual reefs might produce a bigger catch without bolstering fish populations, he said the construction of thousands of them has changed the game, transforming the ocean bottom into one more likely to provide places for fish larvae to develop, generating more fish in general.
"We've totally changed the ecosystem," said Shipp, author of Dr. Bob Shipp's Guide to Fishes of the Gulf of Mexico. "It's nothing like it was before. Before we put those reefs in, it was a sandy mud bottom. The biomass was composed of sea robins and small flatfishes and things like that. When you change the ecosystem to a hardbottom ecosystem, the whole assemblage of species changes, and that's what's happening off of Alabama, and Texas, and Louisiana, as well."
Asked whether we should engage in such a massive manipulation of the marine environment, and whether all this ecological engineering could carry unforeseen consequences, he defended it as the marine equivalent of what we do every day on land.
"It's not natural," he acknowledged. "But we've changed the ecosystem, we think, for the better. The analogy is terrestrial, where you take the forest and convert it to agriculture. That's not natural, to tear down a pine forest and make cornfields out of it, but that's what humans do."
Each reef project is thoroughly vetted by state and federal scientists, said Tom Harvey, spokesman for the Texas Parks and Wildlife Department. Plus, the artificial reefs are intended as compensation for lost recreational services, rather than as strictly conservation projects, he noted. And he provided documents showing that nearly two-thirds of the state's spending of BP compensation money so far is for ecological restoration, such as enhancing bird rookeries, seagrass beds, and sea turtle habitats.
Of the $20.8 billion in compensation BP agreed to pay in a legal settlement over the next decade and a half, $419 million is to go to recreational enhancements, which would include artificial reefs.
Building a new artificial reef requires a permit from the Army Corps of Engineers, which consults with NOAA Fisheries on how the project could affect marine species. However, it's really only assessing the possible contaminants the artificial components could hold and the specific threat to endangered species, rather than doing a holistic analysis on fishing mortality. NOAA Fisheries spokeswoman Kim Amendola confirmed that the broader impact on fish populations is not part of the review.
What is definitely true is that the fake reefs bring in millions of dollars, from both tourists and local residents. A University of Florida study of artificial reefs in six gulf counties found they accounted for $227 million in annual spending for such things as chartering boats, buying fishing supplies, eating in restaurants, and renting hotel rooms.
The economic arguments are strong, the scientific ones more dubious. But after as spectacular a disaster as the Deepwater Horizon spill, which fouled more than 1,000 miles of coastline and killed pelicans, sea turtles, dolphins, and other creatures, it would seem that modesty is called for about our ability to impose our technological will on the world. It may be that an artificial fishing reef is the marine equivalent of transforming a forest into a cornfield — but a cornfield is not going to restore an ecosystem.
Neither are the artificial reefs.
David Fleshler covers the environment for the South Florida Sun-Sentinel.