Black corals (Cirrhipathes spp.)

Description

Black corals fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Black corals description

Also known as whip or wire corals, Cirrhipathes species are long, unbranched corals, which extend up to three metres or more, from a base attached to the reef. They may be straight or form attractive and peculiar twisted or coiled shapes ^{(2) (3)}. The colour of these corals is variable, including pale green, yellow, brown and grey ⁽²⁾. Like all other black corals (those belonging to the order Antipatharia), Cirrhipathes species have a dark skeleton, after which they are named, covered with polyps, the soft bodied, colourful part of the coral. Each polyp is attached to the skeleton at the base, while the other end bears a mouth surrounded by tentacles ⁽⁴⁾. Unlike many corals which retract their polyps during the day or night, Cirrhipathes species can only partly retract their polyps, giving the coral a barbed-wire-like appearance ⁽²⁾.

Black corals biology

Some Cirrhipathes corals have microscopic algae (zooxanthellae) living within their tissues ⁽³⁾. Through photosynthesis, these symbiotic algae produce energy-rich molecules that the coral polyps can use as nutrition. In return, the coral provides the zooxanthellae with protection and access to sunlight ^{(4) (5)}. Those species without zooxanthellae must gain nutrition by another means, by capturing prey in their tentacles. Cirrhipathes species are known to capture any small organism floating in the ocean that measures up to two millimeters long, as well as large marine worms that may be over one centimetre in length ⁽⁶⁾.

Cirrhipathes corals appear to provide a suitable environment for a number of species to inhabit, resulting in a number of fascinating relationships. The shrimps Pontonides unciger and Dasycaris zanzibarica are believed to only be able to survive living within a Cirrhipathes coral, while the male golden damselfish (Amblyglyphidodon aureus) bites off some of the living coral tissue to expose the bare skeleton beneath, where the female will lay her eggs. ⁽⁶⁾ The crab Xenocarcinus tuberculatus is also often found on Cirrhipathes corals, where it collects and covers itself with some of the coral polyps, in an ingenious attempt at camouflaging itself ⁽⁶⁾.

Black corals range

Cirrhipathes corals are found in the Indian and Pacific oceans ⁽³⁾.

Black corals habitat

These corals are found on reefs in tropical and subtropical waters ⁽³⁾.

Black corals status

Listed on Appendix II of CITES ⁽¹⁾.

Black corals threats

All black corals are harvested to be made into jewellery, carvings and tourist souvenirs ⁽⁷⁾, its popularity and high value coming from its dark skeleton, which can be polished to a lustrous sheen ⁽⁸⁾. Cirrhipathes anguina is known to be one of the most commonly traded black coral species, but otherwise, it can be hard to determine the extent to which Cirrhipathes species are affected by such exploitation as identification of black corals in the trade down to the level of genus is difficult ⁽⁸⁾. Black corals around the world are also known to be impacted by habitat degradation, and recently, a small trade in live specimens for aquariums has been reported ⁽⁸⁾.

Black corals conservation

Cirrhipathes corals are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means that trade in this species should be carefully regulated ⁽¹⁾.

Find out more

For further information on the trade in corals see:

• WWF:
  http://www.worldwildlife.org/what/globalmarkets/wildlifetrade/buyersbeware-coral.html
• U.S.Fish & Wildlife Service:
  http://www.fws.gov/news/coral.html

Authentication

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:
arkive@wildscreen.org.uk

Glossary

Algae

Simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.

Photosynthesis

Metabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are made and oxygen is given off as a by-product.

Polyp

Typically sedentary soft-bodied component of Cnidaria (corals, sea pens etc), which comprise of a trunk that is fixed at the base; the mouth is placed at the opposite end of the trunk, and is surrounded by tentacles.

References

1. CITES (September, 2009)
   http://www.cites.org
2. King, D. (1997) Reef Fishes and Corals: East Coast of Southern Africa. Struik Publishers, Cape Town.
3. Hoeksema, B.W. and van Ofwegen, L.P. (2004) Indo-Malayan Reef Corals: A Generic Overview. World Biodiversity Database, CD-ROM Series ETI, Amsterdam. Available at:
   http://ip30.eti.uva.nl/bis/corals.php
4. Barnes, R.D. (1987) Invertebrate Zoology. Fifth Edition. Saunders College Publishing, U.S.
5. Veron, J.E.N. (2000) Corals of the World. Australian Institute of Marine Sciences, Townsville, Australia.
6. Tazioli, S., Bo, M., Boyer, M., Rotinsulu, H. and Bavestrello, G. (2007) Ecological observations of some common Antipatharian corals in the marine park of Bunaken (North Sulawesi, Indonesia). Zoological Studies, 46(2): 227 - 241.
7. Hanfee, F. (1997) Trade in Corals. In: Hoon, H., Chong, K.C., Roy, R., Bierhuizen, B., Rubens, J. and Kanvinde, H. (Eds) Regional Workshop on the Conservation and Sustainable Management of Coral Reefs. FAO, Rome.
8. CITES. (2000) Periodic Review of Animal Taxa in the Appendices. Sixteenth Meeting of the Animals Committee, Shepherdstown, U.S. Available at:
   http://www.cites.org/eng/com/AC/16/index.shtml