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Reef starfish (Stichaster australis) is a species of starfish found in the South Pacific Ocean around New Zealand. A keystone species, the carnivorous starfish plays an important part in reducing the expansion of mussels.

Reef starfish
Starfish orgy (Stichaster australis).jpg
Scientific classification
Kingdom: Animalia
Phylum: Echinodermata
Class: Asteroidea
Order: Forcipulatida
Family: Stichasteridae
Genus: Stichaster
Species: S. australis
Binomial name
Stichaster australis
(Verrill, 1871)



S. australis is pink or purple in color,[1] with 11 arms.[2]

Ecological impactEdit

S. australis rising from the rock near Auckland

Found throughout New Zealand, S. australis is a keystone species in both the North and South Islands, playing an important role in mussel predation.[2][3] In one study on the west coast of the South Island conducted in the 1970s, S. australis was found to have removed a majority of transplanted mussels within two or three months of their placement, while the mussels expanded within six months to cover 20-30% of the low zone when S. australis was removed.[3] Without their predation, the mussels overwhelmed the area, threatening biodiversity.[4][5]

The juveniles of the species are detritivores.[6]


  1. ^ Miller, Michael; Gary Batt (1 January 1973). Reef and Beach Life of New Zealand. Collins. p. 25.
  2. ^ a b Dorfman, Eric (25 April 2006). Sanctuary: New Zealand's Spectacular Nature Reserves. Penguin. p. 28. ISBN 978-0-14-301993-0. Retrieved 29 April 2011.
  3. ^ a b Kareiva, Peter M.; Simon A. Levin (2003). The importance of species: perspectives on expendability and triage. Princeton University Press. p. 29. ISBN 978-0-691-09005-4.
  4. ^ Bayne, Brian Leicester (1976). Marine Mussels, their Ecology and Physiology. Cambridge University Press. p. 54. ISBN 978-0-521-21058-4. Retrieved 29 April 2011.
  5. ^ British Ecological Society (1980). The Journal of Animal Ecology. Blackwell Scientific Publ. p. 674. I have removed a starfish, Stichaster australis Verrill, from an intertidal shoreline in New Zealand, producing rapid domination by a mussel (Perna) at the expense of other resident-space-requiring species (Paine 1971).
  6. ^ Morton, Brian (1993). The marine biology of the South China Sea: proceedings of the First International Conference on the Marine Biology of Hong Kong and the South China Sea, Hong Kong, 28 October-3 November 1990. Hong Kong University Press. p. 369. ISBN 978-962-209-355-3.

External linksEdit