In a perfect world, Mother Nature in her most natural state would be enough for corals to flourish. When that isn’t the case, at least she created the minds that invented the technology needed to restore them to their healthy, vibrant best. The following habitats act like defibrillation paddles, revving up struggling reefs and reviving declining fish populations from Florida to Indonesia and beyond. Chain reactions follow, attracting larger and more-plentiful fish, turtles, sharks and, eventually, divers.

COBIA CAGE
Eleuthera, Bahamas

Sharks bit holes in the cage in the beginning— just another part of research and development for the Island School’s cobia cage project, hatched off Eleuthera in 2003. The goal was to create a sustainable industry for the Bahamas, as well as develop offshore aquaculture with no negative reef impact.

The floating cage is shaped like a bicycle wheel on its side, and measures 80 feet across and 50 feet high. Inside, 5,000 cobia circle. This fish aggregation device, or FAD, lies in a high-energy, high-wave zone where researchers have adapted it to “survive hurricanes and pirates,” says Geoff Walton, technical adviser for the school.

“It’s its own ecosystem,” he says of their aquaculture model. Typically, fish farms claim easy-to-reach waters, such as bays and rivers. The waste quickly clouds water flow.

So far, the company the cobia keep speaks volumes for the health of the water. “Life attracts life,” Walton says. “You raise fish and that creates waste. That breeds algae, attracting cleaner fish, and so on.”

Conch and starfish have settled in on the sand below the cage. Amberjack and yellowtail snappers cruise the site. So do tiger, bull and hammerhead sharks (no, they can’t chomp through the netting).

The abundance of life is pleasing divers, the fish farmers — and scientists. Tests conducted by the University of Miami proved that the water quality here is cleaner than that of surrounding areas because all waste sediment is consumed.

Apparently, you can have your fish and eat it too.

>When to Go The Bahamas is a year-round diving destination, with summer temperatures resembling bathwater.
>Operator Aqua Cat (aquacatcruises.com) visits the cobia cage when conditions allow, which is about half of the time.
>Price Tag A weeklong Aqua Cat cruise costs $2,395 per person.

PEMUTERAN REEF
Bali, Indonesia

Shipwrecks aside, it’s one of the world’s largest artificial reefs, and it’s electrified.

The need for reef resuscitation in Bali, Indonesia, arose after economic hardship drove locals to hunt fish using bombs. That, coupled with record-high temperatures in 1998, nearly wiped out the corals.

“Only 5 percent remained,” says Global Coral Reef Alliance’s Dr. Thomas Goreau of Pemuteran’s near-shore reefs circa 2000 when his team arrived to install 28 biorock coral nurseries spanning 984 feet.

“We don’t like the term ‘artificial reefs’ because we’re actually growing real corals,” Goreau says of the technology that rebuilds limestone substrate. The technique includes a low-voltage electrical field to create ideal conditions for all forms of life, which emit their own metabolic energy. This process has returned 66 of the 82 reef-building corals to Pemuteran.

“We’re directly stimulating their energy and metabolism,” Goreau says. “What we do isn’t electric shock; it’s electric tickle.”
“I can see the change in minutes,” he says of corals transplanted into the energy field. “The polyps brighten in color, expand and start feeding.”

Add up all the minutes, and factor in the Indonesian government’s cooperation in protecting the corals, and it’s no surprise that the reefs of Pemuteran now rival those of the far-flung Indonesian destinations serviced only by live-aboards— and these are only a mere swim from shore.

>When to Go Bali offers warm-water diving year-round, although you might want to skip December through February to avoid the worst of the rainy season.
>Operator Reef Seen Divers’ Resort (reefseenbali.com), located on the beach of Pemuteran Bay, offers bungalow-style accommodations and diving.
>Price Tag A shore dive costs approximately $26, and includes tanks, weights and a guide.

REEF BALLS
Sarasota, Florida

“If you don’t close your eyes, you’ll get dizzy — you’ll be so surrounded by fish,” says Todd Barber, head of the Reef Ball Foundation. He’s talking about the schools of menhaden, a fish that now thrives in Florida’s Sarasota Bay, especially in August. This filter feeder is just one example of how cement mixed with ingenuity can create new ecosystems.

Barber first brought his design — a half-sphere studded with many holes — to Florida in 1995. Before Barber, the bay was an underwater desert: nothing but sand. Despite an average depth of 11 feet, the bottom was receiving no sunlight due to compromised water. Sea grass died. Pollution and overfishing threatened every tier of the food chain, most notably goliath grouper.

Enter Barber.

“We had to decide what each reef ball was for, then backward-design the exact layout,” he says. For example, goliath grouper prefer a large habitat in the center of a circle of smaller reef balls; the hunter feeds on the fish living in the outlying artificial reefs, then returns to its hub to sleep and weather storms.

For divers, goliath grouper sanctuaries might not be the best bets: The reef balls lie 175 feet apart. Instead, head to the M series of reef balls, named for their distance from shore. (For example, M17 is 17 miles out.) It’s here that you’ll be gobsmacked by fishtails, in between turtle sightings.

But, “drop right to the bottom,” warns Barber. “I’ve seen people get seasick inside those balls of fish.”

>When to Go Visibility in the Gulf of Mexico is best in winter.
>Operator Scuba Quest’s (scubaquestusa.com) five shops in the greater Tampa area arrange boat trips to offshore reef balls.
>Price Tag A two-tank boat trip costs $90.

VABBINFARU LOTUS PROJECT
Maldives

The design’s skeleton is said to resemble a lotus flower — a nod to the path of a Buddhist’s soul — but looks equally like a satellite dish. In any case, the 36-footlong outstretched panels and connecting cables increase the structure’s surface area, maximizing the sunlight reaching transplanted coral buds.

Dr. Goreau and the Global Coral Reef Alliance group that installed the unit in the late 1990s had intended to prove that they could grow corals faster and stronger than those nature crafted. The hope was that the end product would be usedinstead of the real thing, which was harvested to make the building material quicklime. Then a 600-watt electrical charge was supplied to stimulate growth.

In 1998, water temperatures spiked. The surrounding corals died, but those nestled within the lotus petals survived.
“That’s when we realized our corals could survive global warming,” says Goreau. He’s quick to point out that although this technology can’t bring corals back from the dead, it’s certainly their best shot at reincarnation.

>When to Go Diving conditions vary little throughout the year.
>Operator Banyan Tree Vabbinfaru (banyantree.com) is a private island in the North Malé atoll with an on-site marine lab.
>Price Tag Villa rates start at $1,200 per night