A large, brightly-coloured anemone, living on sublittoral shells and stones. Northern Ireland has the only known locations in Ireland for this species, and its habitat is threatened by mobile fishing gear and possibly aggregate extraction.

In brief

• Found on numerous sites on the north-east and east coasts of Northern Ireland.
• Sublittoral stones and shell debris from 10 m to considerable depths.
• Can be found throughout the year.
• Northern Ireland has the only known Irish populations of this species.
• Main threats come from habitat disruption, though the species may be vulnerable to climate change in its Northern Ireland locations.

Species description: This is quite a large anemone, its base and relatively smooth column both being about 70 mm in diameter and height. It has two rings of tentacles, and unusually for anemones, the inner one has only six tentacles, whilst the outer has 10-12. The anemone varies in colour, mostly being white, orange, yellowish or brown and often blotched with red. A highly unusual characteristic, which has provoked a considerable amount of research, is its ability to disconnect itself from its substrate and swim in response to threats by predators such as starfish or sea slugs. It appears to do this by flexing its column, but the precise mechanism is still a matter for some debate.

Life cycle: There is no information on this for Northern Ireland, but it has been reported from elsewhere that external fertilisation takes place and the eggs develop into planktonic, plankton-feeding larvae, a mechanism which would encourage wide dispersal.

Similar species: Urticina eques is superficially similar, but is much larger, has two circles of ten tentacles each, and has small wart-like structures on its column.

How to see this species: The species is recorded from numerous sites on the north-east and east coasts of Northern Ireland, notably Rathlin, off Ballycastle, Tor Head, Ballygally Head, and Islandmagee and at the entrance to Belfast Lough. Off County Down it is found off the Copeland Islands and the northern parts of the Outer Ards peninsula. Its habitat is shell debris or stones, to which it attaches itself, and it is only sublittoral, occurring at depths ranging from 10 m to considerable depths. There are no sites elsewhere in Ireland, and in Britain it is recorded from both western and eastern Scotland as well as north-eastern England. It is widespread throughout cold temperate and subarctic regions of the northern hemisphere.

Current status: Stomphia coccinea occurs in numerous locations in Northern Ireland. The species has no legal protection. Northern Ireland holds the entire Irish population of this species.

Why is this species a priority in Northern Ireland?

• Criterion 4: NI stronghold or endemic – both stronghold range/population and designation as ‘endemic’ subject to expert judgement.

Threats:

• The main threat to this species is likely to come from disruption of its habitat by fisheries using mobile bottom trawling or dredging gear, by aggregate extraction.
• However, it is also possible that increases in sea temperature due to climate change might result in the range contracting northwards, and Northern Ireland must be regarded as being as one of the most southerly locations in Europe.

Action: Records of new sites for this species, with details of habitat and population are always valuable. Observations with a photograph can be recorded using iNaturalist, find the MBDP-NI iNaturalist project here.

Alternatively, records can be sent to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257, e-mail cedar.records@nationalmuseumsni.org, or via the online portal.

Objectives:

• Maintain the number of viable populations of the species.
• Maintain the range of the species in Northern Ireland.
• Establish appropriate management of known sites; consider further designation measures.
• Monitor population at key locations.

Conservation:

• Rathlin Island is a Marine Protected Area with multiple designations.
• Strangford Lough is a Marine Protected Area with multiple designations.

Distribution Map from NBN: Stomphia coccinea at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Stomphia coccinea at iNaturalist World Species Observations database.

WoRMS: Stomphia coccinea at World Register of Marine Species. Accepted name: Stomphia coccinea (Müller, 1776). AphiaID: 100854.

Classification: Biota; Animalia; Cnidaria; Anthozoa; Hexacorallia; Actiniaria; Enthemonae; Actinostoloidea; Actinostolidae; Stomphia

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Adapted from text by Allen & Mellon Environmental Ltd. (2026). Stomphia coccinea. (O F Müller, 1776). [In] Priority species, Marine Biodiversity Portal NI. https://www2.habitas.org.uk/marbiop-ni/priorityaccounts.php?item=D11920. Accessed on 2026-09-13