Galapagos coral (Polycyathus isabela)
Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (2).
A rare coral found only around the islands after which it is named, Polycyathus isabela generally forms low colonies in which the individual corallites are joined together (3). Corals of the Caryophylliidae family are usually pale in colour, and as this species is a rather small and cryptic coral, it is easily overlooked (3).
Currently, Polycyathus isabela is known from only three sites around the island of Isabela, in the Galápagos Archipelago (1).
Polycyathus isabela can be found in dimly-lit caves and recesses, at depths between 10 and 23 metres (1).
Polycyathus isabela is an azooxanthellate coral, meaning that this species does not have zooxanthellae, the algae that live inside the tissues of some corals and provide the coral with food (4). Corals without zooxanthellae instead feed on zooplankton, capturing these tiny aquatic animals in their outstretched tentacles (5).
As Polycyathus isabela has only been recorded from three sites (1), the rarity of this species is of some concern. The small population and range size of this coral makes it incredibly vulnerable to any threats that may arise. Whilst it is not clear whether Polycyathus isabela currently does face any threats, it is assumed that both El Niño and climate change could have detrimental effects on this coral (1).
The unique biodiversity of the Galápagos Islands and the surrounding waters is recognised and valued, and thus the region is protected by being designated a Marine Reserve and World Heritage Site (1). Polycyathus isabela is also included in Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully regulated (2). Unfortunately, neither of these measures protects this Vulnerable coral from the threats of natural, or man-induced, climate change.
For further information on conservation in the Galápagos see:
- Charles Darwin Foundation:
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- Algae: simple plants that lack roots, stems and leaves but contain the green pigment chlorophyll. Most occur in marine and freshwater habitats.
- Colonies: relating to corals: corals composed of numerous genetically identical individuals (also referred to as zooids or polyps), which are produced by budding and remain physiologically connected.
- Corallites: the skeletons of individual polyps. Polpys are the soft-bodied components of corals; each polyp comprises a trunk that is fixed at the base, and a mouth that is placed at the opposite end of the trunk and is surrounded by tentacles.
- El Niño: a natural phenomenon that happens every 4 to 12 years, and lasts for several months, when upwelling of cold, nutrient-rich water does not occur. This causes the warming of ocean surface water off the western coast of South America and causes die-offs of plankton and fish. It also affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world.
- Zooplankton: Tiny aquatic animals that drift with currents or swim weakly in water.
IUCN Red List (September, 2007)
CITES (July, 2008)
- Wood, E.M. (1983) Corals of the World. TFH Publications, New Jersey.
- Veron, J. (2000) Corals of the World. Australian Institute of Marine Science, Townsville, Australia.
- Barnes, R.D. (1987) Invertebrate Zoology. Fifth Edition. Saunders College Publishing, US.