Listing: New homes for fish. Available immediately. Spacious, great floor plan, located in an excellent neighborhood. Open habitats include airplanes, shipwrecks, concrete pyramids and contemporary fiberglass structures. All dwellings have a spectacular ocean view.

For the last 50 years, some of Hawaii’s most beautiful natural reefs have been disappearing — reefs that are home to more than 7,000 known species of marine plants and animals, one-quarter of which are found nowhere else in the world. These coral reefs have been threatened by alien invasive species, overfishing, land-based pollution, ocean debris and detrimental climate changes.

This year is the International Year of the Reef (IYOR), a global campaign to raise awareness about the conservation and restoration of coral reefs. Locally, the state of Hawaii is partnering with public, private and nonprofit groups to hold a series of events in 2008 that focus on bringing attention to the ecological, social and cultural value of this “rainforest of the sea.”

According to the IYOR website, coral reefs cover less than one percent of the ocean floor but support an estimated 25 percent of marine life. They provide spawning grounds, refuges and feeding areas for all sorts of organisms.

Several attempts have been made to estimate the value of the world’s coral reefs in terms of dollars, according to the website, which lists the total economic assessment between $100,000 to $600,000 per square kilometer per year.

One local company that has invested substantially in helping to rebuild the ocean ecosystem in Hawaii is Atlantis Adventures, operator of submarine undersea explorations for millions of guests who frequent Maui, Oahu and the Big Island.

Atlantis has spent more than one million dollars since 1989 to sink artificial reefs in the submarines’ dive areas to help nurture coral and develop marine life.

The results have been nothing short of phenomenal. A vibrant ecosystem supporting all sorts of indigenous fish, coral, turtles and other marine life has emerged in Waikiki and Kona, and will soon be established in Lahaina as well.

“What I’ve seen of the life that’s been brought back in the 12 years I’ve been with the company is literally huge,” says Ronald Williams, president and CEO of Atlantis Adventures. “If the artificial reefs weren’t there, you wouldn’t see any of this life.”

The Oahu Atlantis dive site in Waikiki is approximately 5.8 acres and in 1989 consisted of low-growing coral formations spouting up on a volcanic base. “This base provided a solid substrate for the corals to adhere to, but there was also a sparse area of sand flats,” explains Mark Almaraz, general manager of Atlantis’ Oahu operations. “Sand flats do not make a hospitable environment for corals due to the shifting substrate and the smothering effects of sand on corals. The artificial reefs deployed in this area provide a habitat consisting of a solid substrate that is above the shifting sand. These developments of coral and algae are the primary stage in the development of a living reef.”

Off of Waikiki, Atlantis has sunk concrete pyramid structures, Japanese-designed artificial reefs, two airplanes and the remains of two shipwrecks.

In 1989, through the University of Hawaii Sea Grant program, Atlantis funded the installation of experimental pyramid structures, each weighing approximately 27 tons. The reef design provides small spacing at the bottom — protection for juvenile fish — and larger spacing at the top for bigger fish.

In 1990, four spun fiberglass and concrete structures designed by the Asahi Company in Osaka, Japan, were sunk in waters off Waikiki, each one weighing about 25 tons.

The success of these initial structures spurred the sinking of other high-class homes for fish, including two 60-passenger planes formerly owned by Mid Pacific Air, the U.S. Navy tanker ship YO-257 and the Korean fishing boat, San Pedro.

“Artificial reefs are an additional feature to the underwater terrain that offers vertical relief which provides safe refuge for marine organisms of all types and sizes,” says Almaraz. “These vertical reliefs enable marine life to safely travel up the water column while still within protection of the reef.”

On an Atlantis’ submarine tour off of Waikiki; you will most likely see hoards of fish mingling along these artificial reefs in numbers you won’t believe. Schools of silver mackerel flit about, perch and parrotfish scurry by, a moray eel pops his head out to get a good look and a spotted ray glides overhead. There are even a couple of resident reef sharks that camp out under the wings of the planes.

“Atlantis’ guests are often surprised by the amount of marine life existing right offshore from the busy Waikiki beaches,” says Almaraz. “These structures attract a variety of marine life, including algae, corals and reef fish by providing habitats to protect and support them. These smaller organisms, in turn, attract larger reef fish. It is also not unusual to see several turtles resting on the decks of the sunken vessels.”

But sinking all these artificial reefs is no easy task.

“It can be a lengthy process, taking years to gain the necessary approvals and permits,” says Almaraz. “For example, the U.S. Coast Guard completes vessel inspections prior to sinking to ensure the removal of all the engines and transmissions and related fluids. All tanks are to be cleaned and flushed and all hazardous insulations and materials must be removed.”

In addition, engineering groups are contracted to ensure the vessel is structurally sound and will stay at the designated location underwater in the event of a severe storm. Wave studies are completed to determine how much additional weight is required in the vessel, if any, to ensure its position on the ocean floor. The Army Corps of Engineers also needs to be provided with the location of the newly sunken reefs for mariners’ navigation charts.

The state Department of Land and Natural Resources is also heavily involved in ensuring the vessels are not hazardous to marine life or SCUBA divers.

“Large holes are required to be cut into the sides and compartments of the sunken vessels to ensure adequate circulation of fresh sea water through the shipwreck to provide ideal habitats for marine organisms living within the wrecks,” says Almaraz. “In addition, many compartments are welded shut.”

Following two years of preparation, Atlantis most recently sank the Carthaginian replica whaling ship off Lahaina, Maui in 2005. The ship sits in an upright position in 95 feet of water, anchored to a sandy area devoid of coral reef a half-mile offshore.
Within weeks, observers were reporting that various types of marine life were curiously exploring the new digs.

“The biodiversity is increasing as more animals begin to make the Carthaginian their permanent home,” says Jim Walsh, general manager for Atlantis’ Maui operations. “In the beginning, the animals would cruise in for a day or two and move off. It seems we may have gone through a few life cycles of offspring in this area and we are now seeing resident schools of unicorn fish and goat fish make the ship their permanent home. We also have some frog fish and moray eels who have taken up residence as well.”

Walsh notes that Atlantis has been utilizing the Maui Community College’s Marine Option Program to run an ongoing marine life study of the new artificial reef. The students come out several times a year to collect data and all indications point to an increasing biomass of marine life.

In Kona, when conditions permit, Atlantis visits two sunken vessels on the submarine’s route. Both sank in the bay at their mooring about a dozen years ago. “The Predator” is an old World War II landing craft with its landing ramp fully deployed and “The Lady” is a 50-foot yacht that sank after a fire ignited on board.

“Our crew would visit the wrecks to see how the marine life was increasing, and by 2007 we knew that the abundance of fish and coral would be a real ‘wow’ for our guests,” says Mike Stanton, general manager for Atlantis’ Kona operation. “Both vessels are now home to coral outcroppings and significant numbers of different fish species, which regard the wrecks as their homes.”
In addition, the Kona tour’s original dive site was comprised of a 25-acre natural coral fringing reef approximately 18,000 years old, formed after the last ice age retreated. The reef has grown up on the remains of the volcanic lava that flowed in the ocean millions of years ago.

According to Walsh, Atlantis has a responsibility to play an active role as good stewards of precious ocean resources. The organization is constantly looking at new ways to improve its impact on the environment, both through the education of their guests about marine life and by using battery-powered submarines so no pollutants are expelled into the water.

Walsh says, “Atlantis’ philosophy is to be ‘pono’ — to do what is right in order to take care of the ocean.”