Actinia tenebrosa is common along the southern Australian coastline and offshore islands south of the Tropic of Capricorn. It is also found in New Zealand. (QLD, NSW, VIC, SA, TAS, WA)Features:
The Waratah Anemone is the most conspicuous anemone on the temperate Australian coast. Although small in size (30-40 mm high and up to 40 mm wide), it has a distinctive bright red-brown colour when the tentacles are displayed. When the tentacles are contracted and only the column is visible it is much darker in colour.
This species has a wide base that provides a strong attachment to the substrate. The column is smooth. Up to 200 cone-shaped tentacles may be present, usually crowded and arranged in three cycles.Ecology/Way of Life:
The Waratah Anemone is usually abundant on rocks, under ledges and in other shaded positions, but may live in open pools in the intertidal zone. This is the most extensively studied species of Australian and New Zealand anemone and much has been learnt about its reproductive biology, dispersal and connectivity within and between populations. Local aggregations of this species are maintained by asexual reproduction in which minature adults develop in the gastric cavity and are released through the mouth. These young clones often settle close to the parent anemone. Mature animals also produce larvae that are released into the water column, allowing wide dispersal on ocean currents. Interestingly, there is a clear division between northern and southern populations, which may be due to the flow of the eastern Australian current which is thought to act as a barrier to larval dispersal. This is one of the few anemones in which feeding behaviour has been recorded; they eat a wide range of foods and surprisingly even moths can make up much of their diet during certain times!
Along with some other anemones the Waratah Anemone is often eaten by side-gilled sea slugs of the genus Pleurobranchaea. This may limit the anemone's distribution.Interaction with Humans/Threats:
There are no known threats to the Waratah Anemone, however its intertidal habitat makes it vulnerable to pollution, sedimentation and coastal development.Other Comments:
A protein "tenebrosin c" has been isolated from this species and shown to be a cardiac stimulant and haemolytic agent. Also called the Cherry Anemone, this species is probably the best known and most widespread of the Australian anemones — it is surprisingly poorly represented in Australian museum collections.Further Reading:
Ayre, D.J. (1984) The sea anemone Actinia tenebrosa: an opportunistic insectivore. Ophelia 23: 149 – 153.
Ayre, D.J. (1995) Localized adaptation of sea anemone clones: evidence from transplantation over two spatial scales. Journal of Animal Ecology 64: 186 – 196.
Ayre, D.J., Read, J. & Wishart, J. (1991) Genetic subdivision within the eastern Australian population of the sea anemone Actinia tenebrosa. Marine Biology 109: 379 – 390.
Dakin, W.J. (1987) W.J. Dakin's Classic Study Australian Seashores: a guide to the temperate shores for the beach-lover, the naturalist, the shore-fisherman and the student. Angus & Robertson Publishers, North Ryde. 411 pp.
Edgar, G.J. (1997) Australian Marine Life: the plants and animals of temperate waters. Reed Books, Kew. 544 pp.
Fautin, D.G. (2003) Hexacorallians of the World. http://hercules.kgs.ku.edu/hexacoral /anemone2/index.cfm
Ottaway, J.R. (1977) Pleurobranchea novaezelandiae preying on Actinia tenebrosa. New Zealand J. Mar. Freshw. Res. 11: 125 – 130.
Simpson, R.J., Reid, G.E., Moritz, R.L., Morton, C. & Norton, R.S. (1990) Complete amino acid sequence of tenebrosin-C, a cardiac stimulatory and haemolytic protein from the sea anemone Actinia tenebrosa. European Journal of Biochemistry 190: 319 – 328.
Thomas, I.M., Shepherd, S.A. (1982) Sea anemones (Orders Actiniaria, Zoanthidea and Corallimorpharia) In, Shepherd, S.A. & Thomas, I.M. (ed.) Marine Invertebrates of Southern Australia Part I. Handbook of the flora and fauna of South Australia, Government Printer, South Australia, pp. 161 – 169.
Text & map by Carden Wallace & Zoe Richards, Museum of Tropical Queensland.
Photograph by Neville Coleman.Sponsorship welcomed:
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