Inside a coral nursery

Here is a behind the scenes look at coral propagation at the Husbandry Center of Taiwan’s National Museum of Marine Biology and Aquarium (NMMBA). This facility is used for a wide variety of purposes including culturing of live foods, isolation of new animals, breeding area, nursery environment for animals born here, medical care for animals that may need it as well as the propagation of corals – the latter will be focused on in this post.  You could call this a coral farm, parent colonies are maintained and continue to grow in this facility, and the branches of these colonies are propagated by fragmentation – similar to the way new plants are grown from cuttings of existing plants.

The fragments -or ‘frags’- are affixed to a base, soft corals are sewn onto terracotta tiles (15 x 15 cm), on the rugose side as they prefer surface irregularity. As the frags grow, they will attach themselves and encrust onto the base structure and start to develop several branches.

After reaching a larger size they can be put into tanks inside of plastic planter pots.

Hard coral frags on the other hand are suspended in tanks by monofilament lines. When they are big enough they can be epoxied to a hard substrate.hard_smallHard_Large

Why should we grow corals when wild-harvested corals are available right out the front door of the Museum?  It’s our social responsibility to reduce the pressure on the world’s coral reefs.  Every coral fragment we can grow in the facility is one less taken from a natural reef.

At NMMBA coral propagation is used for Aquarium as well as the natural products research they do here. Around 2008 they did a study to see if they should undertake restoration efforts; however, they found that recruitment was high enough that they did not need to. Unfortunately, this is not the case globally and a number of agencies in various other countries are involved in these operations. Frags are attached onto natural live rocks using cyanacrylate glues, which will eventually, naturally, establish their foothold on the live rocks.  Restoration efforts began in the 1970s-1980s (Maragos 1974, Harriot and Fisk 1988) and have been increasingly implemented in the Caribbean targeting threatened staghorn coral, Acropora cervicornis (Lamarck, 1816) and elkhorn coral, Acropora palmate (Lamarck, 1816), which were once the dominant reef-building taxa in the region.  Due to the combination of biological and human induced stressors, Acropora has suffered significant degradation with estimated population declines of up to 95% in some areas (Porter and Meier 1992) leading to their listing as threatened in the US under the Endangered Species Act in 2006 and as critically endangered in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species in 2008.

Although a number of projects are now getting significant funding, using considerable technical expertise and field efforts to establish coral nurseries, and plant out small colonies, the success is varied. While there is a lot of news about how well corals do in the nursery there is little evidence of long-term success once planted out. However, the University of Miami researchers report 92% survival of all outplanted corals since 2007.  Frame1frame2

Other critics of these efforts mention that selection of “resistant” corals are ones that survive in the nursery. The coral reef restoration project Dr Sarah Frias-Torres is running in the Seychelles is a bit different. During the 1998 massive El Nino, which coincided with the Indian Ocean Dipole (the “Indian El Nino”), about 97% of the shallow coral reefs in the tinner granitic island died. This project uses frag from the 3% that survived the massive coral bleaching. This means, they are not growing corals that survive in the open ocean nurseries, but are growing fragments of the corals that survived a major warming event. There is hope that the restored coral reef will have a better chance of survival this time.

Indeed, some doubt that such efforts will be successful, for example these so called “artificial reefs” are often displaced by hurricanes and typhoons (Vize, personal communication). Wave heights can exceed 10m and can move steel frame boxes (average height 5m) lashed together with steel cable that are attached to steel beams and concrete bridge pilings functioning as anchors can be displaced up to 1200m (Turpin and Bortone, 2002). However, it depends on how these structures are installed. Reef Balls is a non-profit and international environmental NGO that has deployed over 1/2 million artificial reefs, which have been noted to have not been displaced by Hurricane Georges in 1993 (Harris, 1998).

In the past 5 years coral nurseries have expanded to ecologically meaningful levels and are beginning to have a considerable impact on the localized recovery of coral reefs (RinkevichForrester et al., 2014). I’m aware the pie of conservation dollars is small and we don’t want to see any slices going into ill-conceived projects that promise restoration with no solid scientific support. Nonetheless, I think we can make the pie bigger, involve public and private sources of funding while working at the same time in science-based conservation and science-based restoration.

Curmudgeons are quick to point out that this is only a local approach (and costly at that) and will not be an effective long-term solution. Sadly, they may be right. As long energy production continues to release C02, oceans will continue to suffer. Nonetheless, in many coral tourism and coral aquaculture areas, including the Maldives, Thailand, Indonesia, Philippines and some Pacific Island States, etc, there are many sound commercial reasons why resort companies and other commercial ventures should and do support local coral nursery and plant-out projects, and personally I support this type activity.

“The time is always right to do what is right” – Martin Luther King


Forrester, G.E., Ferguson, M.A., O’Connell-Rodwell, C.E., Jarecki, L.L. (2014) Long-term survival and colony growth of Acropora palmata fragments transplanted by volunteers for restoration. Aquatic Conservation: Marine and Freshwater Ecosystems 24:81-91.

Harriot, V.J. and Fisk, D.A. (1988) Coral transplantation as a reef management option. Proc 6 Int. Coral Reef Symp. Vol. 2

Harris, L.E. (1988). Post-hurricane site inspection of the reef ball artificial reef submerged breakwater at Gran Dominicus beach resort near La Romana, Dominican Republic. Status report for reef ball

Maragos, J.E. (1974). Coral transplantation: a method to create preserve and manage coral reefs. Sea grant advisory report 74-03-COR-MAR-14. University of Hawaii, Honolulu.

Porter, J.W. and Meier, O.W. (1992) Quantification of loss and change in the Floridian reef coral populations. American Zoologist 32(6): 625-640.

Rinkevich, B. (2013) Rebuilding coral reefs: does active reef restoration lead to sustainable reefs? Current Opinion in Environmental Sustainability 7:28-36.

Turpin, R.K. and Bortone, S.A. (2002) Pre- and post-hurrican assesment of artificial reefs: evidence for potential use a refugia in a fishery management strategy. Journal of Marine Science 59: S74-S82.


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