Historians credit the ancient Persians with constructing the first artificial reef across the mouth of the Tigris, as a barricade against marauding Indian pirates. Today, artificial reef building has morphed into a strange science, with an eclectic array of landlocked junk and engineered implements finding their way to the ocean floor. Reefing materials can include subway cars, armored personnel carriers and even military tanks.
Artificial reefs, sometimes referred to as man-made, placed or deployed reefs, provide a myriad of measurable benefits. First and foremost, they offer marine habitat enrichment, inviting biological replenishment of local populations of marine vertebrates and invertebrates. These reefs offer a plethora of opportunities for both “non-take” (i.e., scuba diving and snorkeling) and “take” (i.e., fishing; both recreational sport and commercial) end users.
Nuts and Bolts
Naturally occurring coral reef systems are found in shallow, warm water environments. There, sunlight penetrates the clear water, providing life to the coral colony below. In the Gulf though, strong currents and the considerable influx of sediment create more tepid waters (temperatures may drop to 60°F during the winter months), limiting natural reefs.
However, the Gulf teems with literally thousands of species of invertebrate plants and animals. Barnacles, corals, sponges, clams, bryozoans and hydroids simply require hard surfaces to thrive. These creatures can begin “reefing” on the ocean floor without the same levels of warmth and sunlight. As these invertebrate colonies establish themselves, the food chain flows upward, creating habitat and providing sustenance for snapper, grouper, mackerel, sharks and other fish.
Artificial Reefs in the Gulf
Abandoned oil rigs, once considered an environmental liability, now provide a rich, environmental resource when “reefed.” After plugging wells, decommissioning platforms and blanking pipelines, these superstructures are toppled into the water. Once sunk, the empty hull provides a prime eco-habit. The process is not without expense, however, and only about two percent of decommissioned rigs have actually made their way to the ocean floor to serve as an aquatic sanctuary.
Louisiana began its artificial reef program in 1986 to take advantage of the proliferation of obsolete oil and gas platforms. According to the Louisiana Department of Wildlife and Fisheries, the Louisiana Fishing Enhancement Act has built 71 offshore reefs utilizing the jackets of 320 obsolete platforms. Often referred to as the “Rigs to Reef” program, the obsolete oil and gas platforms have proved highly successful.
Participating companies offer more than hulled-out rigs for reefs, they also donate one half of their realized savings over a traditional onshore removal to Louisiana’s Artificial Reef Trust Fund. Rigs that aren’t reefed must be towed inshore and scrapped, an expensive process that makes reefing all the more lucrative for oil and gas companies.
The Louisiana reef program has also developed 30 inshore reefs in state waters. Most of these are low-profile reefs comprised of spent limestone or shell. The bulk of the materials come from recycled concrete from the decommissioning of the relic state bridgeworks.
In 1999, the Louisiana reefing program created the world’s largest artificial reef from its Freeport sulfur mine. The structure, located off Grand Isle, is comprised of over 1.5 miles of bridgework and more than 29 structures. Forty armored personnel carriers and an offshore tug can also be found on the bones of the reef.
Florida also has an artificial reef program, and the state has placed more than 2,700 artificial reefs in state and federal waters since the 1940’s. The economic impact of these reefs cannot be understated. In an landmark socioeconomic study of four Florida counties, it was determined that visitors and residents spent 28.3 million person-days using artificial and natural reefs in Florida during a twelve month period.
The study also revealed staggering economic numbers. According to the findings, reef-related expenditures generated in excess of $3 billion in sales with nearly $2 billion in income to residents resulting from some 70,000 reef-related jobs.