Honeycomb coral  (Favites abdita)

Favites abdita is classified as Near Threatened (NT) on the IUCN Red List (1) and listed on Appendix II of CITES (2).

Favites abdita is part of the Faviidae family, a common group of reef-building, ‘stony’ corals, characterised by a hard, calcareous skeleton, called a ‘corallite’. Favites abdita forms what are known as ‘massive’ colonies, meaning that the coral grows in a characteristic mound or dome shape which has roughly similar dimensions (typically close to a metre) in all directions (3). Favites abdita is usually pale brown, darker coloured in more turbid (cloudy) environments, with brown or green oral discs (the soft tissue between the mouth and the surrounding tentacles of the anemone-like polyp), and thick, rounded corallite walls (4).

Favites abdita is found in the Indian Ocean, the Red Sea, the Gulf of Aden, the Arabian Gulf, the East China Sea and the West and Central Pacific Oceans (1) (4).

Favites abdita is found in most reef environments, although it is most common on subtidal and rocky reefs, on reef slopes and in lagoons. It usually inhabits depths between 1 and 15 metres, although it does occur down to 40 metres on rubble substrate that separates different reefs (1).

A honeycomb coral colony is composed of numerous individual polyps, which can reproduce asexually by a process called ‘budding’ (where each polyp divides itself into two or more daughter polyps). Favites abdita is also a hermaphrodite and can  reproduce sexually by producing small, pink eggs and white sperm packets, which are released into the water during a short spawning period, usually around mid-November (4) (5) (6).

Like other reef-building corals, Favites abdita has many microscopic, photosynthetic algae, called zooxanthellae, living within the polyp tissues. The coral and the algae have a mutually beneficial relationship; the coral provides protection for the algae, which in return provide energy and nutrients for the coral through photosynthesis. Both Favites abdita and its zooxanthellae are very sensitive to changes in water temperature and acidity, and any increase in the water temperature greater than one or two degrees above the normal average can stress the coral and cause ‘bleaching’, a phenomenon in which the coral expels it zooxanthellae and turns white (4) (7).

The proportion of corals threatened with extinction has increased dramatically in recent decades, with current estimates suggesting that a third of all coral species have an ‘elevated risk’ of extinction (8). Detailed studies have found that around 20 percent of the world’s coral reefs have been already been destroyed, while at least 24 percent of remaining reefs face a high risk of collapse (9).

Threats to Favites abdita include damage caused by fisheries, pollution from agriculture and industry, human developments, recreation and tourism. Favites abdita is also targeted for the aquarium trade. Corals are particularly affected by the changing global climate, with rising sea temperatures, ocean acidification and mass coral bleaching events all contributing to significant declines in corals. In addition, these varying conditions have greatly increased the susceptibility of corals to disease, a factor which has recently emerged as a major cause of reef deterioration (1) (8) (9).

Favites abdita is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means that all trade in the species should be carefully monitored. It is also known from several Marine Protected Areas. Further research into aspects of Favites abdita’s ecology, abundance, population trends, habitat status and taxonomy is required in order to find out more about how the species is likely to respond to the increasing number of threats throughout its range. The identification and establishment of new protected areas may prove crucial for the conservation of Favites abdita and many other corals, while further research into disease, pathogen and parasite management in corals is also needed (1).

 

View information on this species at the UNEP World Conservation Monitoring Centre.

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For further information on the conservation of coral reefs see:

• Reef Check:
  http://www.reefcheck.org
• The Coral Reef Alliance:
  http://www.coralreefalliance.org