Acropora palmata


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Acropora palmata
Species Authority: (Lamarck, 1816)
Common Name(s):
English Elkhorn Coral

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2ace ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil
Reviewer(s): Livingstone, S., Polidoro, B. & Smith, J. (Global Marine Species Assessment)
This species is listed as Critically Endangered as there has been a population reduction exceeding 80% over the past 30 years due, in particular to the effects of disease, as well as other climate change and human-related factors. This species is particularly susceptible to bleaching. Although the current population is persisting at a very low abundance and the current population trend appears to be stable, there are places where populations continue to decrease and others where there seems to be moderate or localized recovery. Whether mortality continues to exceed growth and recruitment or not, this species requires immediate investigation and monitoring on a regional scale.

Geographic Range [top]

Range Description: This species occurs in the Caribbean, the Gulf of Mexico, Florida, and the Bahamas. While A. cervicornis has been documented further north along the Florida east coast, the northern extension of A. palmata is at Fowey Rocks offshore the Miami area (25°37’ N) (Porter et al. 1987).
Anguilla; Antigua and Barbuda; Bahamas; Barbados; Belize; Bonaire, Sint Eustatius and Saba (Saba, Sint Eustatius); Cayman Islands; Colombia; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Grenada; Guadeloupe; Haiti; Honduras; Jamaica; Mexico; Montserrat; Nicaragua; Panama; Saint Barthélemy; Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Sint Maarten (Dutch part); Trinidad and Tobago; Turks and Caicos Islands; United States; United States Minor Outlying Islands; Venezuela, Bolivarian Republic of; Virgin Islands, British
FAO Marine Fishing Areas:
Atlantic – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: There has been an 80-98% loss of individuals in parts of the Caribbean since the 1980s. There have been some signs of recovery. A second report has validated declines on the order of 97% in the Florida Keys, Jamaica, Dry Tortugas, Belize and St Croix (Acropora BRT 2005) and Puerto Rico (Weil et al. 2003).

There are signs of recovery in populations in some localities. For example, populations in St Croix showed increases from 2001-2003, although larger colonies are not surviving, as large colonies are more affected by stressors (Grober-Dunsmore et al. 2006). Similarly, there are signs of recovery in Puerto Rico and other parts of the southern Caribbean (E. Weil pers. comm.). However, some of these same populations have undergone subsequent declines.

Overall, decline of destroyed and critical reefs in the Caribbean region has been 38% (according to Wilkinson 2004) however there have been much higher population reductions for this species as it is particularly susceptible to disease and bleaching.

The age of first maturity of most reef building corals is typically three to eight years (Wallace 1999) and therefore we assume that average age of mature individuals is greater than eight years. Furthermore, based on average sizes and growth rates, we assume that average generation length is 10 years, unless otherwise stated. Total longevity is not known, but likely to be more than ten years. Therefore any population decline rates for the Red List assessment are measured over at least 30 years. Follow the link below for further details on population decline and generation length estimates.
For further information about this species, see Corals_SupportingDoc.pdf.
A PDF viewer such as Adobe Reader is required.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This species is found in shallow tropical reef ecosystems, favouring outer reef slopes exposed to wave action. It has been recorded to depths of 22 m at Flower Garden Banks in the Gulf of Mexico (Zimmer et al. 2005), but this is a recent range extension potentially due to the results of climate change (Precht and Aronson 2004). The normal depth range is 0.5-5 m (Goreau and Wells 1967), but it can be found up to 40 m.

This species has limited sexual recruitment.
Systems: Marine

Threats [top]

Major Threat(s): The major threat to this species has been disease, specifically white-band disease which is believed to be the primary cause for the region wide acroporid decline during the 1980s (Aronson and Precht, 2001a,b) and is still ongoing (Williams and Miller, 2005). Other major threats include thermal-induced bleaching, storms, and other diseases (Rodriguez-Martinez et al. 2001,Precht et al. 2002,Patterson et al. 2002, Acropora BRT 2005).

Localized declines are associated with: loss of habitat at the recruitment stage due to algal overgrowth and sedimentation; predation by snails; mortality by endolithic sponges; ship groundings, anchor damage, trampling, and marine debris. The long-term threat of reduced skeletal integrity due to ocean acidification is of particular concern due to the species' presence in wave-swept environments.

In general, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification.

Coral disease has emerged as a serious threat to coral reefs worldwide and a major cause of reef deterioration (Weil et al. 2006). The numbers of diseases and coral species affected, as well as the distribution of diseases have all increased dramatically within the last decade (Porter et al. 2001, Green and Bruckner 2000, Sutherland et al. 2004, Weil 2004). Coral disease epizootics have resulted in significant losses of coral cover and were implicated in the dramatic decline of acroporids in the Florida Keys (Aronson and Precht 2001, Porter et al. 2001, Patterson et al. 2002). Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs at high risk of collapse.

Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities.

The severity of these combined threats to the global population of each individual species is not known.

Conservation Actions [top]

Conservation Actions: Listed on CITES Appendix II and Threatened on the US Endangered Species Act. In the US, it is present in several MPAs, including Florida Keys National Marine Sanctuary, Biscayne N.P., Dry Tortugas National Park, Buck Island Reef National Monument and Flower Garden Banks National Marine Sanctuary. Also present Hol Chan Marine Reserve (Belize), Exuma Cays Land and Sea Park (Bahamas). In US waters, it is illegal to harvest corals for commercial purposes. In response to ship grounding and hurricanes, there have been efforts to salvage damaged corals and reattach them in acroporid habitats.

More information is needed to assist the recovery of acroporids including survival and fecundity by age, sexual and asexual recruitment, population information, juvenile population dynamics, importance of habitat variables to recruitment and survivorship, and location of populations showing signs of recovery (Bruckner, 2002). Further research is needed into disease etiology, and effectiveness of current restoration methods.

Bibliography [top]

Acropora Biological Review Team. 2005. Atlantic Acropora Status Review Document. National Marine Fisheries Service, Southeast Regional Office.

Aeby, G.S., Work, T., Coles, S., and Lewis, T. 2006. Coral Disease Across the Hawaiian Archipelago. EOS, Transactions, American Geophysical Union 87(36): suppl.

Aronson, R.B. and Precht, W.F. 2001 a. Evolutionary Paleoecology of Caribbean Coral Reefs. In: Allmon, W.D. and Bottjer, D.J. (eds), Evolutionary Paleoecology: The ecological context of macroevolutionary change., pp. 171-233. Columbia University Press, New York.

Aronson, R.B. and Precht, W.F. 2001b. White-band disease and the changing face of Caribbean coral reefs. Hydrobiologia 460: 25-38.

Bruckner, A.W. 2002. Proceedings of the Acropora Workshop: Potential Application of the U.S. Endangered Species Act as a Conservation Strategy.: 199. Miami, FL.

Bruno, J.F., Selig, E.R., Casey, K.S., Page, C.A., Willis, B.L., Harvell, C.D., Sweatman, H., and Melendy, A.M. 2007. Thermal stress and coral cover as drivers of coral disease outbreaks. PLoS Biology 5(6): e124.

Colgan, M.W. 1987. Coral Reef Recovery on Guam (Micronesia) After Catastrophic Predation by Acanthaster Planci. Ecology 68(6): 1592-1605.

Goreau, T.F. and Wells, J.W. 1967. The shallow-water Scleractinia of Jamaica: Revised list of species and their vertical distribution range. Bulletin of Marine Science 17: 442-453.

Green, E.P. and Bruckner, A.W. 2000. The significance of coral disease epizootiology for coral reef conservation. Biological Conservation 96: 347-361.

Grober-Dunsmore, R., Bonito, V. and Frazer, T.K. 2006. Potential inhibitors to recovery of Acropora palmata populations in St. John, US Virgin Islands. Marine Ecology Progress Series 321: 123-132.

IUCN. 2008. 2008 IUCN Red List of Threatened Species. Available at: (Accessed: 5 October 2008).

Jacobson, D.M. 2006. Fine Scale Temporal and Spatial Dynamics of a Marshall Islands Coral Disease Outbreak: Evidence for Temperature Forcing. EOS, Transactions, American Geophysical Union 87(36): suppl.

Patterson, K.L., Porter, J.W., Ritchie, K.B., Polson, S.W., Mueller E., Peters, E.C., Santavy, D.L., Smith, G.W. 2002. The etiology of white pox, a lethal disease of the Caribbean elkhorn coral, Acropora palmata. Proc Natl Acad Sci 99: 8725-8730.

Porter, J.W. 1987. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (south Florida) – Reef-building corals. US Fish and Wildlife Serv Biol Rep 82(11.73). US Army Corp of Engineers, TR EL-82-4, 23.

Porter, J.W., Dustan, P., Jaap, W.C., Patterson, K.L., Kosmynin, V., Meier, O.W., Patterson, M.E., and Parsons, M. 2001. Patterns of spread of coral disease in the Florida Keys. Hydrobiologia 460(1-3): 1-24.

Precht, W.F. and Aronson, R.B. 2004. Climate flickers and range shifts of reef corals. Front Ecol Environ 2(6): 307-314.

Precht, W.F., Bruckner, A.W., Aronson, R.B., and Bruckner, R.J. 2002. Endangered acroporid corals of the Caribbean. Coral Reefs 21: 41-42.

Rodriguez-Martinez, R.E., Banaszak, A.T., Jordan-Dahlgren, E. 2001. Necrotic patches affect Acropora palmata (Scleractinia: Acroporidae) in the Mexican Caribbean. Dis Aquat Org 47: 229-234.

Sutherland, K.P., Porter, J.W., and Torres, C. 2004. Disease and immunity in Caribbean and Indo-Pacific zooxanthellate corals. Marine ecology progress series 266: 273-302.

Veron, J.E.N. 2000. Corals of the World, Volume 1. Australian Institute of Marine Science, Townsville MC, Australia.

Wallace, C.C. 1999. Staghorn Corals of the World: a revision of the coral genus Acropora. CSIRO, Collingwood.

Weil, E. 2003. The corals and coral reefs of Venezuela. In: Jorge Cortes (ed.), Latin American Coral Reefs, Elseview Science B.V.

Weil, E. 2004. Coral reef diseases in the wider Caribbean. In: E. Rosenberg and Y. Loya (eds), Coral Health and Diseases, pp. 35-68. Springer Verlag, NY.

Weil, E. 2006. Coral, Ocotocoral and sponge diversity in the reefs of the Jaragua National Park, Dominican Republic. Rev. Bio. Trop. 54(2): 423-443.

Weil, E., Hernandez, E., Bruckner, A., Ortiz, A., Nemeth, M. and Ruiz, H. 2003. Status of Acroporid populations in Puerto Rico. Caribbean Acropora Workshop: Potential Application of the US Endagered Species Act as a Conservation Strategy: 71-92.

Wilkinson, C. 2004. Status of coral reefs of the world: 2004. Australian Institute of Marine Science, Townsville, Queensland, Australia.

Williams, D.E. and Miller, M.W. 2005. Coral disease outbreak: pattern, prevalence and transmission in Acropora cervicornis. Marine Ecology Progress Series 301 119-128 301: 119-128.

Willis, B., Page, C and Dinsdale, E. 2004. Coral disease on the Great Barrier Reef. In: E. Rosenber and Y. Loya (eds), Coral Health and Disease, pp. 69-104. Springer-Verlag Berlin Heidelberg.

Citation: Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil 2008. Acropora palmata. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 03 September 2015.
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