Pavona coral (Pavona cactus)

GenusPavona (1)

Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (2)

Pavona cactus is a scleractinian coral, meaning that it is a ‘hard’ coral with a limestone skeleton (3). It is pale brown or greenish-brown in colour and typically has thin, upright fronds and twisted branches (4) (5), but may develop thicker fronds when growing in shallow areas with strong waves (4). Pavona cactus may grow as an isolated colony or may form large colonies that can cover over ten metres (4) (5). Until very recently it was thought to be the same species as the cactus coral (Pavona decussata), but studies have now shown that Pavona decussata and Pavona cactus are in fact two distinct species (4). 

Pavona cactus is an Indo-Pacific coral, with a range that extends from Japan to Australia and from the Red Sea to Tahiti (6).

This coral occurs in lagoons and on the upper slopes of reefs (5) (7), where there is a slight current (7), as well as turbid waters protected from waves (5). It is often found growing amid colonies of the cactus coral Pavona decussata (4).

On the Great Barrier Reef Pavona cactus has been shown to reproduce sexually, although this species also reproduces asexually. It does so by fragmentation (8), a form of asexual reproduction where a new organism grows from a fragment of the parent into a mature, fully grown individual. However, more work is needed on this species’ biology as little information is available at present.

In common with many other corals, Pavona cactus has microscopic algae (zooxanthellae) living within its tissues. Through photosynthesis, these symbiotic algae produce energy-rich molecules that the coral can use as nutrition. In return, the coral provides the zooxanthellae with protection and access to sunlight (9) (10). 

Pavona cactus is facing a number of threats, including rising water temperatures due to climate change, resulting in coral bleaching. During coral bleaching, the symbiotic algae are expelled, leaving the corals weak and vulnerable to an increasing variety of harmful diseases. This is a threat faced by all corals, although it has been observed that Pavona cactus is less susceptible to bleaching effects than some other coral species (11).

Another problem facing Pavona cactus is the increasing amount of carbon dioxide in the atmosphere. Because Pavona cactus and other scleractiniancorals grow through building their calcified skeleton, the increase of carbon dioxide in the atmosphere reduces the carbonate ions available for the corals to use, thus limiting their growth(12).

Now that Pavona cactus has been confirmed as a species in its own right, further research into its biology will help inform future conservation actions for this species. Sadly, on a larger scale, it has been deemed that the environmental threats caused by climate change may already be too severe for most corals. A meeting in October 2009 saw scientists discuss the ambitious idea of freezing coral in liquid nitrogen so as to preserve them for reintroduction when the global climate has stabilized (13).

For further information on the conservation of coral reefs see:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (March, 2010)
  2. CITES (March, 2010)
  3. Willis, B.L. and Ayre, D.J. (1985) Asexual reproduction and genetic determination of growth form in the coral Pavona cactus: biochemical, genetic and immunogenic evidence. Oecologia, 65: 516-525.
  4. Pillay, K. Asahida, T. Chen, C. Terashima, H. and Ida, H. (2006) ITS ribosomal DNA distinctions and the genetic structures of populations of two sympatric species of Pavona (Cnidaria: Sceleractina) from Mauritius. Zoological Studies, 45(1): 132-144.
  5. Veron, J.E.N. (1986) Corals of Australia and the Indo-Pacific. Australian Institute of Marine Science, Townsville, Australia.
  6. Sea Life Base (November, 2009)
  7. Erhardt, H. and Moosleitner, H. (1998) Marine Atlas, Volume 2: The Joint Aquarium Care of Invertebrates. Mergus, Melle, Germany. 
  8. Ayre, D.J. and Wills, B.L. (1988) Population structure in the coral Pavona cactus: clonal genotypes show little phenotypic plasticity. Marine Biology, 99: 495-505.
  9. Barnes, R.D. (1987) Invertebrate Zoology. Fifth Edition. Saunders College Publishing, U.S.
  10. Veron, J.E.N. (2000) Corals of the World. Australian Institute of Marine Sciences, Townsville, Australia.
  11. Craig, P., Birkeland, C. and Belliveau, S. (2001) High temperatures tolerated by a diverse assemblage of shallow-water corals in American Samoa. Coral Reefs, 20: 185-189.
  12. Marubini, F., Ferrier-Pages, C. and Cuif, J.P. (2003) Suppression of skeletal growth in scleractinian corals by decreasing ambient carbonate-ion concentration: a cross-family comparison. Proceedings of the Royal Society, 270: 179-184.
  13. McGrath, M. (2009) Freezer Plan to Save Coral. BBC News, Online. Available at: