Sea-fan anemone  (Amphianthus dohrnii)

Sea fan anemone

Facts

Kingdom Animalia
Phylum Cnidaria
Class Anthozoa
Order Actiniaria
Family Hormathiidae
Genus Amphianthus (1)
Size Diameter of oral disk: up to 10 mm (2)

Status

Not listed or protected by any conservation directives, conventions or legislation (3).

Description

This small anemone is pink, orange, red or buff-coloured with streaks of white (2), and has up to around 80 irregularly arranged small tentacles (2). The scientific name of this group of sea anemones Amphianthus refers to their flower-like appearance; amphi means 'near' and anthus is from the Greek for flower, 'anthos' (4). It usually occurs attached to sea fans, hence the common name (2).

Range

In Great Britain, this species is most often recorded off Plymouth. It has also been found off the west coast of Scotland, in Cornwall, and around Lundy Island in the Bristol Channel, and occurs around the south and southwest coasts of Ireland (2). In the rest of the world, it occurs along the Atlantic coast of France, reaching into the western Mediterranean (2). Throughout this range, the sea-fan anemone appears to be rare (3).

Habitat

Attaches to sea fans such as the pink sea fan (Eunicella verrucosa) in England, the northern sea fan (Swiftia pallida) in Scotland, and similar organisms, and occurs in the 'sublittoral zone', inhabiting fairly deep water (2).

Biology

The sea-fan anemone reproduces asexually by shedding parts of its base behind it as it moves along. These fragments develop into tiny anemones (2), which are often closely packed together (3). This mode of reproduction means that this species has rather limited powers of dispersal. However, sexual reproduction probably does occur, and the wide distribution of this species suggests that there must be some form of dispersal as yet undetected (2). The lifespan is between 20 and 100 years (2).

Threats

Although this species has never been particularly common, it has nevertheless undergone a decline (3). A number of causes of this decline have been proposed, including changes in water masses; since the 1970s water masses have become colder, which has caused problems for species at the northernmost limit of their distribution (3). Furthermore, contamination of the water resulting from various human activities may affect larval and adult survival (3).

Conservation

The sea-fan anemone is a UK Biodiversity Action Plan (UK BAP) priority species, and as such, a Species Action Plan has been produced to guide its conservation (3). Although there is no conservation action currently targeted at this species, the main host in the British Isles, the rare pink sea fan (Eunicella verrucosa), is afforded full legal protection under Schedule 5 of the Wildlife and Countryside Act, 1981, and is therefore protected against killing, taking, injuring, and sale (3). The conservation of these two delicate and sensitive species is closely tied.

Further Information

For more on this species see the Marine Life Information Network (marLIN):
http://www.marlin.ac.uk

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

Asexually: of asexual reproduction: reproduction that does not involve the formation of sex cells ('gametes'). In many species, asexual reproduction can occur by fission (or in plants 'vegetative reproduction'); part of the organism breaks away and develops into a separate individual. Some animals, including vertebrates can develop from unfertilised eggs, this process, known as parthenogenesis gives rise to offspring that are genetically identical to the parent
Larval: of the stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Sublittoral: a marine zone between the littoral zone (the shallow zone where light reaches the bed, subject to submersion and exposure by tides) and depths of around 200m.

References

  1. Heaxacorallians of the world. (July 2002):
    http://hercules.kgs.ku.edu/hexacoral/anemone2/classifications/current_classification.htm
  2. Jackson, A., 2000. Sea fan anemone, Amphianthus dhornii. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [On-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29 July 2002]. Available from:
    http://www.marlin.ac.uk
  3. UK BAP (July 2002):
    http://www.ukbap.org.uk
  4. Jobling, J. A. (1991) A dictionary of scientific bird names. Oxford University Press, Oxford.
  5. National Biodiversity Network Species Dictionary ( January 2003)
    http://www.nhm.ac.uk/nbn