Bowl coral  (Turbinaria peltata)

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

The reef-building coral Turbinaria peltata forms colonies of flat, overlapping plates and occasionally vertical columns. A single colony, comprised of numerous individual polyps, can grow up to several metres in diameter. When the large, greyish-brown polyps are extended, as they frequently are during the day, the surface of the colony has a furry, carpet-like appearance (3) (4).

Turbinaria peltata is distributed widely in shallow waters of the Indian Ocean (including the Red sea and the Arabian Gulf) and the western Pacific (1) (3).

Most commonly found at depths of 9 to 20 metres in protected environments, such as shallow rocky foreshores and sandy reef flats (1) (4).

Unlike most corals within the family Dendrophyllidae, Turbinaria peltata is zooxanthellate. Zooxanthellate corals live in symbiosis with unicellular algae known as zooxanthellae, which are essential to their growth and survival. Protected within the coral tissue, the algae provide their hosts with nutrients and energy, whilst also helping to remove metabolic wastes. The cost of this symbiosis is that zooxanthellate corals are constrained to live in relatively shallow waters where the algae are able to photosynthesise (4).

All Turbinaria species breed during the autumn in falling sea temperatures. Unlike most corals which are hermaphroditic (4), Turbinaria have separate male and female sexes, and probably release gametes for external fertilisation (3).

Around one third of the world’s reef building corals are threatened with extinction (5). The principal threat to corals is the rise in sea temperature associated with global climate change. This leads to coral bleaching, where the symbiotic algae are expelled, leaving the corals weak and vulnerable to an increasing variety of harmful diseases. Climate change is also expected to increase ocean acidification and result in a greater frequency of extreme weather events such as destructive storms. This is not to mention the localised threats to coral reefs from pollution, destructive fishing practices, invasive species, human development, and other activities (1) (5).

Although Turbinaria peltata is still relatively widespread and common, evidence of an overall global decline in coral habitat is an indication that this species is almost certainly declining. On top of the multitudinous threats already described, Turbinaria peltata is heavily harvested in the aquarium trade, particularly in Indonesia, where pieces are exported in the tens of thousands (1).

In addition to being listed on Appendix II of CITES, which makes it an offence to trade Turbinaria peltata without a permit, this coral falls within several Marine Protected Areas across its range. To specifically conserve Turbinaria peltata, recommendations have been made for a raft of studies into various aspects of its taxonomy, biology and ecology, including an assessment of threats and potential recovery techniques. Given the current extent to which it is exploited in the aquarium trade, fisheries management and monitoring of the effects of harvesting are a particular priority in Indonesia (1).

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

Environment Agency - Abu Dhabi is a principal sponsor of ARKive. EAD is working to protect and conserve the environment as well as promoting sustainable development in the Emirate of Abu Dhabi.

For further information on the conservation of coral reefs see:

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