Moon jellyfish (Aurelia aurita)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help

Summary

Description

Aurelia aurita has a smooth, flattened saucer-shaped bell (the umbrella) with eight simple marginal lobes. The umbrella is colourless, while the radial canals, oral arms and gonads are typically mauve, violet, reddish, pink or yellowish in colour. Aurelia aurita usually grows to approximately 25 cm in diameter but can reach 40 cm. The umbrella is quite thick, thinning towards the edge, with numerous short, hollow tentacles forming a fringe around the edge. These short tentacles are ringed by numerous stinging cells (nematocysts). There are four interfolded gonads that form a horseshoe or near circle shape in the centre of the umbrella. Eight branched and eight un-branched canals connect to the marginal ring-canal of the umbrella. The mouth is formed on a projection on the underside of the umbrella (the manubrium). Four thickened oral arms, each with a central groove, edged by thinner folded lips and lined with small tentacle-like processes approximately 2 mm long. The surface of the oral arms is covered with nematocysts, crowded together near the tips of the tentacles. The oral arms are slightly shorter than the radius of the umbrella. The stomach consists of four circular shaped interradial gastric pouches connected to the mouth by grooves.

Recorded distribution in Britain and Ireland

Aurelia aurita can be found all round the coasts of Britain and Ireland.

Global distribution

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Habitat

Aurelia aurita is Britain's most common jellyfish. It is sporadic in its appearance, forming massive local populations in some areas but totally absent in other areas for some years. Aurelia aurita is a pelagic species but may be found washed up on the shore. It is known to occur up estuaries and into harbours and is especially common in Scottish sea lochs.

Depth range

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Identifying features

  • Umbrella thins towards the edge and has a distinctive fringe of short, hollow tentacles.
  • Four, purple-blue gonads form a characteristic horseshoe-shape, contained almost completely within the gastric cavity.
  • Gonads do not extend below the sub-umbrella surface as in many other species of jellyfish.

Additional information

Aurelia aurita has an interesting life history. The sexes are separate, the sperm are taken into the female via the mouth and fertilization occurs internally. Pits in the oral arms act as a temporary brood chamber holding the eggs until they develop into free-swimming larvae (planula larvae). Following a brief swimming period the planulae attach to hard substratum and develop into tiny sessile animals (scyphistomae). These reproduce by asexual budding and release free-swimming tiny immature jellyfish (ephyrae). The ephyrae feed on plankton and will generally reach maturity at around 3 months. However, some ephyrae may take up to two years to grow into sexually-reproducing adult medusae (Ruppert & Barnes, 1994).

Aurelia aurita feed, but not exclusively, on plankton and can at times occur in massive swarms, which may be so dense as to give the sea a uniform red colour and slow the passage of small boats (Russell, 1970).

Listed by

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Further information sources

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Bibliography

  1. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  2. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line] http://www.jncc.gov.uk/mermaid

  3. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.

  4. Ruppert, E.E. & Barnes, R.D., 1994. Invertebrate zoology (6th ed.). Fort Worth, USA: Saunders College Publishing.

  5. Russell, F.S., 1970. The medusae of the British Isles. Vol II - Pelagic Scyphozoa, with a supplement to the first volume on hydromedusae. Cambridge University Press

Datasets

  1. Bristol Regional Environmental Records Centre, 2017. BRERC species records recorded over 15 years ago. Occurrence dataset: https://doi.org/10.15468/h1ln5p accessed via GBIF.org on 2018-09-25.

  2. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  3. Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: https://doi.org/10.15468/hcgqsi accessed via GBIF.org on 2018-09-25.

  4. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38

  5. Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01

  6. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2014. Occurrence dataset: https://doi.org/10.15468/erweal accessed via GBIF.org on 2018-09-27.

  7. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: https://doi.org/10.15468/xtrbvy accessed via GBIF.org on 2018-09-27.

  8. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.

  9. Lancashire Environment Record Network, 2018. LERN Records. Occurrence dataset: https://doi.org/10.15468/esxc9a accessed via GBIF.org on 2018-10-01.

  10. Manx Biological Recording Partnership, 2017. Isle of Man wildlife records from 01/01/2000 to 13/02/2017. Occurrence dataset: https://doi.org/10.15468/mopwow accessed via GBIF.org on 2018-10-01.

  11. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset: https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.

  12. Marine Conservation Society, 2018. UK Jellyfish Sightings from 2003 to 2015. Occurrence dataset: https://www.mcsuk.org/ accessed via NBNAtlas.org on 2018-10-01.

  13. Merseyside BioBank., 2018. Merseyside BioBank (unverified). Occurrence dataset: https://doi.org/10.15468/iou2ld accessed via GBIF.org on 2018-10-01.

  14. Merseyside BioBank., 2018. Merseyside BioBank Active Naturalists (unverified). Occurrence dataset: https://doi.org/10.15468/smzyqf accessed via GBIF.org on 2018-10-01.

  15. National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.

  16. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  17. North East Scotland Biological Records Centre, 2017. NE Scotland other invertebrate records 1800-2010. Occurrence dataset: https://doi.org/10.15468/ifjfxz accessed via GBIF.org on 2018-10-01.

  18. OBIS (Ocean Biodiversity Information System),  2025. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2025-05-21

  19. Outer Hebrides Biological Recording, 2018. Invertebrates (except insects), Outer Hebrides. Occurrence dataset: https://doi.org/10.15468/hpavud accessed via GBIF.org on 2018-10-01.

  20. South East Wales Biodiversity Records Centre, 2018. Dr Mary Gillham Archive Project. Occurance dataset: http://www.sewbrec.org.uk/ accessed via NBNAtlas.org on 2018-10-02

  21. South East Wales Biodiversity Records Centre, 2023. SEWBReC Marine and other Aquatic Invertebrates (South East Wales). Occurrence dataset:https://doi.org/10.15468/zxy1n6 accessed via GBIF.org on 2024-09-27.

  22. Suffolk Biodiversity Information Service., 2017. Suffolk Biodiversity Information Service (SBIS) Dataset. Occurrence dataset: https://doi.org/10.15468/ab4vwo accessed via GBIF.org on 2018-10-02.

  23. The Wildlife Information Centre, 2018. TWIC Biodiversity Field Trip Data (1995-present). Occurrence dataset: https://doi.org/10.15468/ljc0ke accessed via GBIF.org on 2018-10-02.

  24. West Wales Biodiversity Information Centre, 2018. Seatrust Cetacean Records West Wales. Occurrence dataset: https://doi.org/10.15468/ecsmqh accessed via GBIF.org on 2018-10-02.

Citation

This review can be cited as:

Heard, J.R. 2004. Aurelia aurita Moon jellyfish. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 21-05-2025]. Available from: https://www.marlin.ac.uk/species/detail/2089

Last Updated: 07/10/2004