Eco – Enhancing Marine Projects

By John C. Walch

Coral Reefs: These two five lettered words can inspire a multitude of emotions and images. Brilliant colored fishes gliding past mounds of gold, blue and green corals. Snorkelers silhouetted on the surface of azure blue water, while strange-looking creatures slither amongst sunken treasures. Sea fans and turtle grass wave peacefully in the current.

The origin of sustenance for much of the World’s human population, coral reefs and their related ecosystems are the most productive and biologically rich on Earth. However, coral reefs, mangroves and seagrass beds are in serious jeopardy. Natural events such as storms can inflict periodic stress and strains but the primary agent of degradation is human activity. Preservation and conservation efforts need to remain a top priority as well as reclamation of damaged reefs and the creation of new ecosystems whenever and wherever appropriate. Just as land development must be environmentally sensitive so must marine based projects.

Large stacked stone style breakwaters have been a traditional approach used when forming and preserving sandy beach coastlines. However, when the developer of Maiden Island, Antigua, applied for a permit to install an armor stone breakwater, the Antigua Department of Fisheries had concerns that this conventional method would critically impact the threatened Caribbean conch (Strombus gigas) seagrass bed habitat. An alternative Reef Ball™ artificial reef structure with adaptations designed to preserve conch habitat was suggested and approved.

The adaptation entailed prefabricating the concrete Reef Ball modules with open bottoms to allow sea grasses to flourish under them. The Reef Ball modules were also placed with space between them to create corridors for the seabed inhabitants. Eight different sizes and over 100 different design styles of Reef Ball modules were incorporated into this project to more closely mimic a natural reef.

The original fringing reef on the windward side of Maiden Island had been reduced to coral rubble and pieces of loose live rock when hurricane Luis collided with Antigua eight years ago. Using advanced surveying techniques the Reef Ball modules were designed to create a breakwater while being placed around, rather than on coral formations.

Ariel view of Reef Ball breakwater and underwater view of Reef Ball placement around existing coral formation.

Scientifically designed to attract and provide habitat for fish, lobster, and other marine life, each Reef Ball module on average produces about 180 kilograms (400 lbs) of biomass (animal or plant life) annually. Over 3,500 Reef Ball modules were constructed on the Island of Antigua. The construction site had an average of 100 workers building Reef Ball modules 24 hours per day, 7 days a week for a period of 2 months. Using Reef Ball Foundation’s and local concrete experts, a special concrete mix was developed that allowed the Reef Ball modules to be deployed rapidly, sometimes within 18 hours of being cast, while still retaining the special marine friendly formulations that make the concrete’s pH match that of natural seawater. The pH balancing and unique textured surface of the Reef Ball modules is accomplished so that coral larvae and other marine life can easily attach allowing the modules to develop into a natural biological reef.

“Standing room only, inside and outside of the Reef Ball modules”

One thousand two hundred of these Reef Ball modules were deployed from a barge on the windward side of Maiden Island to form the “windward” breakwater reef/dive-snorkel trail. The remaining 2,000 modules were built for the “lee side” breakwater, and west side of the Island’s Reef Ball red mangrove planting project.

Barge deployment was precise

Working with coral scientists and propagation experts, the Reef Ball Foundation Coral Team has developed specialized methods for asexually reproducing both hard and soft corals and planting them onto Reef Ball modules. Each species of coral requires slightly different techniques for optimal success but the end results are the same, ready to transplant coral plugs. Most of the coral plugs were planted on the Reef Ball modules within a few hours of being made. However, in the beginning of the project, the coral plugs were being produced faster than the Reef Ball modules were being deployed, hence coral nurseries were established for storage for planting in the days that followed.

The coral plugs fit quickly and without much effort into the multiple coral plug receptacles cast into each module. While scientists have previously demonstrated asexual coral propagation and transplanting techniques on a small scale, the innovative coral plug/adapter design feature developed by the Reef Ball Foundation greatly increases the efficiency of transplanting live coral fragments. The project in Antigua successfully demonstrates that large-scale coral propagation and transplanting can be done economically and safely using these techniques.

Verification of effectiveness of this applied technology is seen in this project, wherein over 5,000 coral colonies were propagated and transplanted in only fourteen days by the mostly volunteer Reef Ball Foundation workforce of 15 people.

Coral plugs in tray, planting plug on Reef Ball, finished product 30 days after planting.

Thirty different species of imperiled hard and soft corals including 3,000 free living rose corals, and literally tons of brain corals, Gorgonian soft corals, Elk Horn coral, etc. were rescued from dredge operations surrounding the Maiden Island. Several species of these corals were fragmented into smaller segments (replicating natural asexual coral reproduction) including threatened Sea Fans (Gorgonia spp.), Elkhorn coral (Acropora palmata), Staghorn coral (A. cervicornis), as well as the less common Fused Staghorn (A. prolifera-robusta). Other fragmented species included Finger corals (Porites porties and P.devaricata), Pillar coral (Dendrogyra cylindricus), Diffuse Ivory Tree coral (Oculina diffusa), and Yellow Pencil coral (Madracis mirabilis), to mention a few.

In addition to the thousands of coral plugs, post-hurricane stabilization included 4.5 tons of unstable live rocks that were relocated and secured to the Reef Ball modules so that they would not damage the coral reef in the event of a future hurricane visit. The Reef Ball modules were also aquascaped and planted with coral species that do not lend themselves well to fragmentation (i.e. Diploria sp., Colpophyllia sp. and Meandrina sp.) commonly referred to as brain corals along with Mustard Hill (Porites asteroids, etc.), anemones, desired macro algal, and sponges just to state a few. The transplanting of imperiled and rescued corals along with live rock and other invertebrates greatly accelerate the formation and biodiversity of the Reef Ball restoration coral reef, improving the water quality and marine life habitat (especially for juvenile fish).

Biodiversity of transplanted species enhanced habitat.

The latest scientific techniques were employed during the restoration and expansion of this living reef system. For example over 500 sea urchins (Echinometra lucunter) were transferred to the new reef to serve as the janitorial crew, keeping the new coral transplants free of algal overgrowth.

Scientifically designed spiny lobster (Panulirus argus) settlement substrate/refuge mats were also incorporated into the reef to enhance lobster larval survivability. These settlement mats have previously proven to be highly successful under the right conditions. In addition, graduate students from NOVA Southwestern College are testing a slightly modified version within the scientific control section of the reef. These invertebrate enhancer mats were included on 8 of the 16 standard size Reef Ball modules as part of a long-term scientific study. The mats are prime habitat for amphipods and other like micro invertebrates, an important link in the juvenile fish food chain.

Based on the positive results for juvenile fish recruitment from previous studies, the hollow center of some of the Reef Ball modules were filled 1/3 full with a mixture of rocks and empty conch shells to create additional complex enhanced habitat for juvenile and small fish. Fish corridors were mapped into the floor plan to assist the juvenile fish in their migration from shallow water reef protection to deep water. A pinnacle of Reef Ball modules was strategically located directly up current off the reef at the end of the corridor to serve as a spawning location for Gray Snapper (Lutjanus griseus) and other like species.

The Reef Ball Foundation also teamed up with the Maiden Island developer’s horticultural staff to conduct a mangrove-planting project. Over 4,000 cultured Red Mangrove seedlings were imported from a university in South Florida.

In comparison to the environmental assessment that was prepared by an independent third party prior to the start of the project, the new coral reef breakwater has had a very positive influence on the marine life in the area. Originally there were 11 fish species observed during the preparation period of the assessment. The volunteer workforce documented an impressive increased 76 fish species, 71 invertebrate spp along with turtles and dolphins encouraged by the new habitat. The combination of a very talented team and proven marine restoration techniques used in this project effectively created a natural complex and diverse ecosystem. The ecosystem restoration concept was so successfully completed that The Antigua Department of Fisheries is now considering the protection of the new and neighboring natural reefs, mangrove stands, seagrass beds, the spawning ground “Pinnacle” and coral bank reserve.

The good news for the developer is that the whole project cost less than the traditional breakwater would have! The good news for the environment is that the Reef Ball coral reef breakwater was much more environmentally sensitive and produced an end product with far greater beauty and function. It is possible for marine based projects to be environmentally sensitive and to leave our coral reef ecosystems in better state after construction of breakwaters.

The Maiden Island, Antigua, reef restoration and erosion control project is just one of 3,500 projects in 43 countries that have deployed over half a million Reef Ball modules in an effort to improve marine ecosystems.

The Reef Ball Foundation’s Coral Reef Propagation and Reef Rescue teams are composed of experts and concerned coral reef enthusiasts from around the world. These dedicated individuals are willing to volunteer their time to assure that the words Coral Reefs do not spawn images of extinct marine life and degradation.

For more information on this and other Reef Ball projects visit the Reef Ball Foundation’s website at www.artificialreefs.org

John C. Walch, Owner of Ocean Worlds Consulting helped develop the coral propagation methods and technology used in this project and several other Reef Ball Foundation projects. John serves as co-team leader of the Reef Ball Foundation Coral Team and can be reached at Johnwalc@AOL.com