Mariculture, Aquaculture & Restoration (MAR)

Home to some of the healthiest, largest, and most pristine coral reef systems in the world, Papua New Guinea is an ideal location to establish a sustainable export trade of aquarium fish and corals.  A wide variety of “high end” aquarium trade corals can be found in abundance throughout the fringing and barrier reefs of PNG, as well as many species of highly sought after fish and invertebrates.

In the interest of maintaining this high state of health and diversity that can be found on PNG’s reefs, the Mariculture, Aquaculture, Restoration (MAR) division was created and incorporated into the SEASMART program.  The main objectives of MAR:  to explore sea based mariculture and land based aquaculture possibilities for high value aquarium trade species that can not be sustainably collected from the wild, as well as to seek out restoration projects, in an effort to preserve the fragile ecosystem on which the SEASMART program so desperately depends.

Though the MAR division was largely inactive over the course of the three-year SEASMART program, MAR activities quickly intensified in the first quarter of 2010, with the appointment of the MAR division manager.   Since then, MAR has become one of the main forefronts of the program, with the primary focus of establishing coral mariculture operations in coastal PNG communities.

Coral Mariculture

Coral mariculture, sometimes called in-situ coral propagation, is based on coral’s natural ability to reproduce asexually.  When a fragment of a coral colony is removed, this removed fragment continues to live and grow on its own as a new colony.  In coral mariculture, platforms are placed in shallow water, and tiny coral fragments collected from local reefs are placed on these platforms and allowed to grow until they reach a suitable size.  Some of the fragments are allowed to grow until they can be fragmented themselves, which leads to the production of F2, second generation maricultured corals. Corals are the ideal product to mariculture at the community level because they are relatively easy and inexpensive to propagate, hold a high retail value, have few predators, and their culture poses a low environmental impact (Kinch and Teitelbaum 2008,)

At present, no corals are exported from PNG for the aquarium trade.  However, the sale and export of maricultured corals has the potential to generate a substantial source of income for PNG’s coastal villages. By implementing a coral mariculture program that involves having coastal villagers farm and sell their own coral, it is possible to establish a coral export trade in PNG that is both profitable and highly sustainable.

As the aquarium hobby in the United States, Europe, and Asia progresses with new technology, the ability for aquarists to keep corals alive in their home aquariums becomes easier and easier.  As a result, more and more people around the world are developing a demand for live aquarium corals.  In fact, corals are becoming the main focus of many hobbyist aquariums, with fish playing just a supporting role in the aquarium community.

The global demand for aquarium corals is on the rise, and that demand has increased drastically over the past 10 years.  It is estimated that the United States alone imports over 1.5 million live stony corals for the aquarium trade annually (Brian Tissot et al, 2009).  Most of these corals come from Indonesia, Fiji, and the Solomon Islands, with some also coming from Malaysia, Tonga, Vanuatu, Marshall Islands, and Australia.  Some of the corals are maricultured in the sea, but most are wild collected.

The wild collection of corals for any purpose is a largely unsustainable practice.  Coral colonies are slow to grow, and can have a very slow recruitment rate.  This means that if reef areas are stripped of live coral, the areas can remain dead and unproductive for decades.

Mariculturing corals however can produce a high volume of sustainably farmed corals of various species.  These corals can be then be sold to the aquarium trade, can be used for decorative “curio” coral, can be used for lime production, or can even be replanted onto devastated reef areas!  The SEASMART coral mariculture program is designed to use 70% of all farmed maricultured corals to be exported to the world aquarium market, while 30% of the corals will be replanted onto destroyed reefs in SEASMART led reef restoration projects.

MAR division has currently established one coral mariculture operation.  This mariculture site is located at Fisherman Island, Central Province.  The mariculture site consists of ten metal platforms submerged in about 5 meters of water, with 20 women from fisherman island employed as coral farmers.  The platforms are projected to produce over 10,000 coral fragments annually, generating an estimated 50,000 Kina for the coral farmers of Fisherman Island.

Maricultured corals are also expected to generate a significant amount of money for the Export Trial Facility.  Because corals are in such high demand, the availability of corals to SEASMSART customers in the US and Europe is expected to drive sales and exports from the ETF to much higher levels than they are at present.

Coral Mariculture Specifics

The following is a summary and pictorial guide to the SEASMART coral mariculture program created thus far.  For an in-depth, detailed guide, see the MAR division manual, located in the appendix of this report.

Construction and Deployment of Mariculture Platforms

10 coral mariculture platforms were constructed and deployed during the second quarter of 2010. These platforms were constructed of angle iron and galvanized wire mesh.   There are 2 basic models of platforms.  Five of them are “double tiered” and 5 are “single tiered.”  The double-tiered design has 2 levels on which to place corals.   The bottom level receives less light, and therefore is capable of holding corals that prefer to live in the shade or in deeper water.    Both models are capable of holding over 700 coral fragments at any given time.

The platforms require no welding to assemble.  The angle iron is simply cut to the appropriate length with a cutting disc, and then holes are drilled through the iron allowing the pieces to be bolted together.  The wire mesh is then cut into 60cm X 100cm pieces, and the pieces are laid across the platform.

All ten mariculture platforms have been deployed to the waters of Fisherman Island.

Figure 6:  A) Image of angle iron pieces cut to length and waiting assembly.  B) Image of wire mesh cut to appropriate size and laid on platform.  Note that the wire mesh is removable to allow for easily bringing corals to the surface for upkeep and maintenance.  C) Fully assembled platform being loaded onto a dinghy at Ela Beach Pier.  D) Diver giving a deployed platform a final inspection.

Cement Disc Production

Tiny coral fragments need to be attached to a suitable base for them to be able to grow.  After much deliberation, the MAR division opted to use cement discs as the base to attach coral fragments to.  Cement is ideal because it holds up well in the sea, it is readily available throughout PNG, and it cab be molded into any shape/size desired.  The cement also allows for the stamping of serial numbers into the cement while it is still wet.  This enables the creation of a traceability system, with each coral fragment assigned its own number.

Each disc is individually and sequentially numbered, starting from 00001.  The discs were also labeled with a “SS” for SEASMART, a “PNG, ”and an “FI” for Fisherman Island.  This allows for the complete traceability of each coral fragment, and also will help with the marketing of these coral fragments as truly traceable and truly sustainably farmed corals from PNG.

The labeling process for each disc involves pressing letters and numbers into the cement while the cement is still wet.  10mm number and letter punch sets were used as the pressing tool.  This method was utilized because it is cheaper than buying plastic tags for each fragment, and the information is permanently attached to the disc, and thus will be permanently attached to the coral, all the way through mariculture in the sea, to the retail shop.

Figure 7:  A) Cement discs being mass-produced.  B) 50mm cement disc.  The holes allow the disc to be easily tied down to wire mesh racks.

Mother Colony Collection

In order to begin coral mariculture, pieces of wild coral colonies had to be collected from the reefs around Fisherman Island and transported to the mariculture platforms.  These pieces are known as “mother colonies.”

The process of collecting mother colonies basically involves selecting ideal colonies for mariculture in the wild, and then removing half of the selected colony to be transported to the mariculture platforms.  No more than half of any wild coral is ever removed from the reef, ensuring that minimal environmental disturbance is created by mother colony collection.

The locations of the coral collection sites are marked with GPS.  A coral collection site is defined as any area of reef within 100 meters of the marked GPS position.  This system ensures that each mother colony is traceable to within 100 meters from the original location that it was found.

After collection, each mother colony is tied to its own 3-inch diameter cement disc.  The number stamped into the disc is recorded, along with the date collected, the collection site the coral was taken from, and the coral’s genus and species.  A photo is also taken of each mother colony.  The data and photo are entered into a data base, resulting in a database that can tell any interested party where each coral came from, what species of coral it is, when it was collected, and a photo of what it looks like.

Figure 8:  A) Removing half of an Acropora sp colony.  A hammer and chisel is used to gently remove the desired portion.  B) Diver holding collected corals underwater.  A partitioned crate is used to prevent the corals from touching one another.  C) Holding collected corals on a boat.  D) Attaching a collected Acropora colony to a 3-inch cement disc.

Figure 9: A trained SEASMART coral farmer caring for collected mother colonies on her mariculture platform

 Coral Tagging

Because we only remove up to half of a wild coral colony to be used as mariculture brood stock, the other half of the coral colony remains in place on the reef.  In an effort to monitor the recovery of these remaining corals, the MAR division has developed a simple tagging system, by which 20 percent of harvested corals have their wild remnants tagged.

The tags basically work by suspending a float 1 meter above the coral colony with monofilament line, and tying the free end of the line to the remaining portion of the wild colony after half of the colony is harvested.  A stamped metal tag with the mother colony number is also attached to the monofilament.

Tagged corals are photographed immediately before we remove half, and then immediately after we remove half of the colony.  The coral will be re-photographed at 2 weeks, 1 month, 3 months, 6 months, and 1 year from the date it was fragmented.

Tagged corals are marked with GPS to within 100 meters of their exact location, and their depth is noted.  Finding the tagged corals for monitoring at a later date is dependent on divers finding the orange floating tag, suspended about 1 meter above the coral, in open water.

Figure 10: A) Acropora sp colony in the wild, before half is harvested for mariculture.  B) Same Acropora sp colony immediately after portion was removed for mariculture.  C) Tag marking a harvested Diploastrea sp coral. Note the float suspended approx 1 meter above the coral to allow for easily finding the coral for later monitoring.

Coral Propagation

Propagation, or fragmentation, is the process of fragmenting the collected mother colonies into multiple tiny pieces, which are in turn attached to their own smaller cement discs.


Figure 11:  A) Acropora fragment being tied down to a 50mm diameter cement disc.  B) Multiple Acropora fragments being tied down to a mesh wire rack.  C) Mesh wire rack being loaded with coral fragments.

 Farmer Training

Farmer training involves teaching selected villagers everything they need to know to become proficient coral farmers.  This includes:

  • Basic Coral Biology and Coral Reef Ecology
  • Mariculture Platform Construction and Deployment
  • Cement Disc Production
  • Gear assignment and care
  • Coral Propagation
  • Record Keeping
  • Safety
  • Coral Care and Platform Maintenance

Figure 12: Coral Farmer Training being conducted at Fisherman Island.

Figure 13:  GIS Image of Mariculture Platform Location and Coral Collection Sites

Reef Restoration

As stated above, 30percent of all maricultured corals will be planted back onto local reefs that are in need of recovery.  These reefs include those that have suffered from anthropological damage from boat anchors or blast fishing, or from natural damage caused by storms, mass bleaching events, or crown of thorns star outbreaks.  Damaged reefs are considered to have less than 20% live coral cover.

Figure 14: Graphic depicting a maricultured coral fragment being planted back onto a destroyed reef.  Reef image taken near Nago Island, Kavieng, 2010. Storms and crown of thorns stars wiped out many reefs there.

Reef restoration works by planting farmed corals directly onto the damaged reef.  This can be accomplished by simply “plugging” the coral fragments into a hole or crevice in the rock, or by gluing the coral down with an underwater epoxy.

When corals are manually replanted onto a damaged reef in this manner, reef recovery that could take many decades to occur by natural recruitment can be reduced to just a few years.

Before reef restoration efforts begin, the proposed area is carefully surveyed to get baseline data on live coral cover and abundance of reef fish and invertebrate species.  The area to be restored is then mapped out with GIS, and marked off with underwater markers.  Maricultured coral fragments are then placed into the restoration zone, and are carefully monitored over the next several weeks, months, and years.  Additional surveys are then conducted to note the improvements, if any, that resulted from replanting the corals.

Future Plans of MAR

Coral Mariculture Expansion and Reef Restoration

Coral mariculture’s ability to provide an alternative source of income to low income communities will have a life changing and positive impact on coastal people around the nation.  In addition, coral mariculture will bring to these communities an ability to restore local reef areas that have been diminished of live coral cover.  These reef restoration efforts will greatly enhance local reef health and productivity, which is directly related to food fish availability and fisheries security.

SEASMART plans to implement coral mariculture operations in all of PNG’s coastal provinces, producing tens of thousands of maricultured coral fragments annually.  Because each province will have slightly different coral species or different color variants of the same species, mariculturing corals from all areas of PNG will produce a huge variety of extremely sought after corals. Though PNG does not export any corals for the aquarium trade at present, PNG is poised to become the dominant global supplier of sustainably farmed corals to the aquarium market if mariculture efforts are allowed to expand across the nation.

Other Mariculture and Aquaculture Possibilities

SEASMART is open to pursuing the possibility of culturing several other types of aquarium species that can not be sustainably collected.

On the top the list are Giant clams of genus Tridacnid.  Giant clams are successfully cultured in many other nations, some for food purposes, and some for the aquarium trade.  Tridacnid clams are extremely high value animals in the aquarium market, and their culture could represent a significant source of income for people of PNG and the PNG aquarium trade.

 Coral Gardens

Coral Gardens are small patch reefs in shallow water that are maintained at a high state of health and beauty to act as ideal snorkel destinations for recreational snorkelers.   Coral gardens can be well managed natural reefs, or can be created by constructing an artificial reef, bringing the beauty of a coral reef to an area that was previously void of one.  Artificial coral gardens can be created by placing structures into the sea that corals can attach to.  These coral gardens rapidly attract fish populations, and often become popular snorkel and diving destinations.

The structures that can be placed in the sea to provide the foundation for the artificial reef can be anything from old rubber car tires, to old vehicles, to concrete mounds with caves formed throughout.  Maricultured coral fragments will then be attached to the structures, to seed them with initial coral colonies.  SEASMART plans to provide the maricultured coral fragments to local volunteers that want to assist with seeding the coral gardens with living coral.  SEASMART aims to gain as much local support and help in the creation of coral gardens, with the intention of educating all that participate about coral reef ecology and coral biology.  SEASMART also hopes that creating such gardens will create a sense of awareness as to the importance of wild reefs, and their delicate nature.

Beach Clean Ups

Beach clean ups are a highly effective tool for creating awareness about the amount of trash and rubbish that can be found on the local beaches.  Often, people will not realize just how much trash is on a beach until they can see it all collected into an enormous pile.

Beach clean ups are effective at accomplishing two major elements:

  • Removing trash from a beach and increasing the beach’s beauty
  • Creating a cause for locals to establish proper trash disposal techniques and reduce littering rubbish into the ocean.

SEASMART conducted its first beach clean up event of 24 April 2010, in honor of World Earth Day.  Staff from SEASMART ventured out to Fisherman Island to join forces with locals there, and proceeded to remove over 400 KG of trash from the small beach in front of the village.

As the SEASMART program develops and expands, the MAR division will stand ready to extend coral mariculture and reef restoration programs to all of Papua New Guinea’s coastal provinces.  Hundreds of Coastal villagers around the nation will be able to generate a new source of income off of growing tiny pieces of coral for the aquarium trade, while thousands of coastal Papua New Guineans will benefit from the healthier reef systems that coral farming and restoration projects will achieve throughout all of PNG’s coastal provinces.

In addition, the high value and exotic coral species that will be farmed by PNG villagers will be in high demand by aquarists all over the world.  Already, before any coral has even be exported from PNG, aquarists and aquarium livestock import companies are excited about the prospect of receiving corals from this “new” area.

The sustainably maricultured coral fragments that are produced under the SEASMART program will become well known around the globe for their superior quality, much like the aquarium fish under the SEASMART program have already done.  Each maricultured coral fragment will proudly display the letters “PNG,” permanently pressed into its cement base, ensuring that the world learns that Papua New Guinea is the next global leader in sustainable coral mariculture.

Continue with “Management Area Planning (MAP)”