Cauliflower corals (Pocillopora spp.)

Also known as: brown stem corals, brush corals
KingdomAnimalia
PhylumCnidaria
ClassAnthozoa
OrderScleractinia
FamilyPocilloporidae
GenusPocillopora (1)

Listed on Appendix II of CITES (1).

This hardy, widespread and common coral can easily be identified by the presence of wart-like growths, called verrucae, which cover the colonies (2). The colonies can be fairly solid and dome-shaped, or branching with branches that are either flattened and blade-like, or fine and irregular (3). Species of Pocillopora corals vary greatly in appearance, depending on environmental conditions. For example, species situated on shallow reefs with heavy wave action are often stunted, whilst those in deep water are thin and open. The tentacles born on each polyp are usually only extended at night (2).

Pocillopora corals are distributed widely in the Indian and Pacific Oceans (3).

Cauliflower corals occur in habitats ranging from exposed reef fronts to protected lagoons and lower reef slopes. One species, P. molokensis, occurs only in deep water (3).

The polyps of Pocillopora corals are hermaphrodite; they each possess four sets of male and four sets of female gonads (2). Pocillopora can reproduce asexually as well as sexually. Unlike many corals, the coral larvae develop inside the polyps rather than in the water column. When the mature larvae are released into the water, the larvae can remain free-swimming for several weeks before settling on the substrate. They can even become partly polyp-like during this period, enabling feeding to occur before settling and commencing skeleton formation (2). Pocillopora can also successfully reproduce asexually via fragmentation (5).

Pocillopora corals are hermatypic corals, and therefore have microscopic algae (zooxanthellae) living within their tissues. Through photosynthesis, these symbiotic algae produce energy-rich molecules that the coral polyps can use as nutrition (2). In return, the coral provides the zooxanthellae with protection, and access to sunlight. The wide geographic distribution of Pocillopora corals is probably due to rafting, whereby small colonies attach to floating objects, such as pumice, where they can travel great distance to remote places (3). The polyps can also obtain nutrition by capturing tiny prey using their tentacles.

Cauliflower corals face the many threats that are impacting coral reefs globally. It is estimated that 20 percent of the world’s coral reefs have already been effectively destroyed and show no immediate prospects of recovery, and 24 percent of the world’s reefs are under imminent risk of collapse due to human pressures. These human impacts include poor land management practices that are releasing more sediment, nutrients and pollutants into the oceans and stressing the fragile reef ecosystem. Over fishing has ‘knock-on’ effects that results in the increase of macro-algae that can out-compete and smother corals, and fishing using destructive methods physically devastates the reef. A further potential threat is the increase of coral bleaching events, as a result of global climate change (4). Another potential threat is over-harvesting. Pocillopora is one of four genera that constitute the majority of the dead coral trade. Indonesia and Fiji have export quotas for this coral, but in 1997, the amount of Pocillopora traded greatly exceeded the quota, showing a failure to regulate the trade (5). However, Pocillopora is thought to be fairly resilient to collection due to their success at asexual reproduction through fragmentation (5).

Pocillopora 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). Pocillopora is one of the genera that can be fairly successively cultivated, due to its fast growth rate and the ease at which it can be propagated by fragmentation. Growing tips are collected from large colonies in the wild, and the fragments are cultivated in the sea suspended from fishing lines until large enough to be sold in the aquarium trade. Whilst the initial collection does have impact on wild populations, cultivation poses less threat than complete wild harvesting (5). Pocillopora corals will form part of the marine community in many marine protected areas (MPAs), which offer coral reefs a degree of protection, and there are many calls from non-governmental organisations for larger MPAs to ensure the persistence of these unique and fascinating ecosystems (4).

For further information on this species see Veron, J.E.N. (1986) Corals of Australia and the Indo-Pacific. Angus & Robertson Publishers, London, UK.

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:
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  1. CITES (June, 2007)
    http://www.cites.org
  2. Veron, J.E.N. (1986) Corals of Australia and the Indo-Pacific. Angus & Robertson Publishers, London, UK.
  3. Veron, J.E.N. (2000) Corals of the World. Australian Institute of Marine Science, Townsville, Australia.
  4. Green, E. and Shirley, F. (1999) The Global Trade in Corals. World Conservation Press, Cambridge, UK.
  5. Wilkinson, C. (2004) Status of Coral Reefs of the World. Australian Institute of Marine Science, Townsville, Australia.